Does Testosterone vary through the year?

Several studies have asked this, with differing results. But some find that testosterone does appear to vary through the year to a moderate degree. It usually peaks around the Autumn, then drops through the winter to a low in the Spring.

Paris 1975: five healthy medical students and biochemists living in Paris age 26-32. “The peak of plasma testosterone was in November (909 ± 42.7 ng/dl) and the trough was in May (640 ±51.1 ng/dl)”) (source)

1974-1975 in Nijmegen, The Netherlands: 15 healthy men age 24-45. Testosterone averaged 666 ng/dl in April 1974, 744 in July, 762 in October, 665 in January 1975, and 631 in April 1975. (source)

That was the average, but there was a lot of individual variation. Some men peaked in July and some peaked in October. One man looked like this: April: 781 ng/dl, July: 1084, October: 1144, January: 586, April 778. That guy didn’t like January much! However, most of them did not change as much as that. Maybe that guy had very low Vitamin D or something.

Boston, Massachusets in the USA in the 2000’s  – Among 30-79 year old men, testosterone rose until July, reaching 470 ng/dl, and then began dropping to a low in December of 385 ng/dl (source) The study didn’t find the differences to be significant however.

Does your son have low testosterone?

If you’re worried that your son may have low testosterone, you might be right. There are industrial chemicals polluting the environment, drinking water, and food, which are able to dramatically damage testosterone levels (and other hormones too). Thankfully, there is a lot we can do to protect ourselves and get testosterone levels back up to where they naturally should be!

How to tell if it’s low testosterone

Taking into account his personality, a high testosterone guy will be energetic, cheerful, interested in socializing, playing sports, and so on. Low testosterone guys often aren’t as enthusiastic for these things. Also if there seems to be an unusual and “hormonal looking” fat gain and absence of muscle; a soft and flabby body, that’s a strong sign of low testosterone. To really know, you can get a blood test done to measure testosterone.

Plastics and chemicals in the water

Get a good water filter that can remove all the endocrine disruptor substances. Pesticides, microplastics, pharmaceuticals, literal estrogen, heavy metals, and chlorine are all frequently present in modern drinking water, and they all lower testosterone. A good water filter can remove them all.

Pesticides and additives in the food

Organic food is a must in certain categories. Grain type food is very important to get organic, because grains are heavily sprayed with pesticide typically, and this accumulates in the final food product. (Source) Organic grains are certified to be free of pesticides. (In reality there can be a small amount of pesticides that accumulates here, but we do our best! Buying straight from a small natural farmer or even growing your own food would be the ways to do better, and even then, a tiny amount of pesticide residue could blow in accidentally.)

You also want to avoid unnatural, weird additives like dyes, artificial flavors, and preservatives.

Seed oils (vegetable oils) in junk food

Junk food is typically made with vegetable oil, also known as seed oil, which may possibly lower testosterone. More info about that can be found in our  article about that here.

Snacks made without seed oil are few and far between, which is why we are making potato chips fried in real tallow and no seed oil. No additives either. You’ll find them at

Go here to get tallow fried potato chips
Click the horse to get the potato chips! (Clicking opens )

Home products that are natural and won’t hurt the hormones

It would be good to get natural versions of these products, and not chemical-filled ones: Soap, shampoo, moisturizer, sunscreen, laundry detergent, dishwasher detergent, shower curtain. Here’s our guide to laundry detergents.

Get 100% cotton or 100% wool instead of polyester underwear. Polyester is a type of plastic, believe it or not, so it can produce microplastics.

We’ve posted some all natural underwear in our guide here.

Finally, a word about lifestyle

You may have suspected that lifestyle also plays a role in this, and you are right. Getting good exercise, not being overweight, not being sedentary and spending all day in front of a screen are all very important. However, it may be a bit of a vicious cycle. A low testosterone guy could spend all his time being inactive, on his computer, not socializing, not playing sports because he isn’t craving outside, energetic, active, social things like a high testosterone guy would be. So fixing the lifestyle and the chemicals at the same time might feed on each other and get testosterone levels up!

Does Bright Light Therapy Increase Testosterone?

Get more light, especially in the morning after waking up, and your testosterone levels will thank you! Fluorescent lights, such as office lighting, are not bright enough to wake you up and raise your testosterone. You need light as bright as natural daylight for a naturally high hormone level.

Exposure to bright light, especially sunlight, raises testosterone a lot.

Italian researchers took men with low testosterone and nearly doubled their levels in just two weeks, by exposing them to 30 minutes of bright light soon after waking up.

They went from a very low 210 ng/dl of testosterone to a more acceptable 360 ng/dl. Your body needs to see bright light right after you wake up to make you understand that it’s morning and it’s time to be awake and energetic! This seems to regulate the chemicals in your body, including testosterone. It’s not just men with low testosterone that benefit, another study found that in young healthy guys, Leutinizing Hormone, which is the hormone that tells testosterone to rise, was increased almost 70% by early morning light exposure. This study used a 1000 lux light box. The Italian researchers in the first study used a 10,000 lux light box similar to this:

Verilux HappyLight Luxe – UV-Free LED Therapy Lamp, Bright White Light with 10,000 Lux

Natural sunlight would be preferable, but some people don’t have access to this and so a light box would be a pretty good alternative. Even just normal lamps in your house would be beneficial. Turn on the lights, darkness will lower your testosterone! I’ve found that fluorescent lights in office buildings, despite being glaring and unpleasant, actually seem to be too dim to really wake you up and so they likely keep your testosterone low. You need sunlight!

Office buildings are typically 500 lux, while direct sunlight is 32,000 lux or more. The 10,000 lux that the researchers used is on the low end of ambient light outside. This daylight was sufficient to raise the the men’s testosterone, but direct sunlight’s much higher lux seems to raise testosterone even more. Florescent lights are so dim compared to daylight that they don’t even seem to wake you up. If you get 30 minutes or more of morning sunlight instead of going straight from your dim house to your dim office, you might find that you don’t need quite so many cups of coffee to stay energetic during the day!

Source of lux ratings:

UV Light Could Raise Testosterone

In 1939, a Dr. Myerson experimented with shining a bright UV light on depressed men. Dr. Myerson measured the excretion of androsterone, a testosterone metabolite. He found that this increased by 120% over the course of a 5 day treatment, where he shone UV light on the front of the body for a mere 8-20 minutes a day. Over the next 8 days, the androsterone levels slowly fell back to the earlier levels, but he found that he could always make them rise again by repeating the UV exposure. This study makes it clear that frequent sunlight exposure is the key. It seems that each sunbathing session will raise testosterone a little more until it reaches a high level, where it will stay as long as you keep sunbathing pretty frequently.

Sunlight for Testosterone

Sunlight is the gold standard for testosterone elevation, because it is by far the brightest, it contains UV rays, and its spectrum is the one that humans are biologically accustomed to. Sunlight raises Vitamin D, and Vitamin D apparently raises testosterone. This is one of the reasons that sunbathing would raise testosterone, but also the bright light by itself is important for raising testosterone, independent of Vitamin D. This is why taking a Vitamin D supplement is not a sufficient replacement for sun exposure.

Darkness Lowers Testosterone

Hamsters kept in permanent darkness for a while had their testosterone levels crash to apparently castrate levels. When they were put back into a natural light cycle, their testosterone came back up to normal. (Source)

How to Schedule Your Light Exposure

It’s important to be in bright light after waking up, and all through the day. It seems that this will keep your testosterone high. Ideally you would be in direct sunlight throughout the whole morning when there is minimal risk of sunburn (until 10AM or 11AM during daylight savings time). Then you’d get some direct sunlight after this point for the UV benefits. UV seems to raise testosterone, but it also can sunburn you and cause damage, so you should start with 15 minutes exposure, or whatever won’t burn you. I think it would be best to slowly increase this sun exposure as well, maybe up to 2 hours if you can handle it. Then the rest of the day, you’d get bright light on you from sunlight through a UV blocking window, or from a very well lit room. After 4PM (or 5PM during daylight savings time) the UV is minimal again, and you can be in direct sunshine without really worrying about sunburn.

How is modern life altering our bodies and minds?

Some people think we are better today than ever before, while others look to the past as a golden age. It seems that neither view is exactly correct. There are some improvements today, but there are also some troubling physical and mental health trends that have arisen quite recently. There are also some changes with effects that are unknown.

  • Body temperature has dropped nearly 1 degree on average. This suggests widespread thyroid concerns.
  • TSH may have risen, suggesting thyroid issues.
  • Digit ratio changes to a lower testosterone profile
  • Testosterone has dropped from a projected 900 ng/dl (this is a rough estimate) some time before 1960 to about 700 ng/dl in 1970 to about 400 ng/dl today. See our article for a lot more details about the drop in testosterone.
  • Skull and body frame changes
  • Height increase by quite a lot. This is a good change!
  • Flynn effect – IQ has risen apparently!
  • Autistic traits on the rise
  • Grip strength has dropped – this could have more to do with neural matters than muscles.
  • Incidence of mental distress and mental disorder has risen. About 4x more American high school and college students have low-empathy, pseudo-psychopathic traits.
  • People have many less friends on average than they used to.
  • Incidence of degenerative disease has increased tremendously.
  • But a huge improvement in the treatment of infectious disease.
  • Reaction time slowed from about 0.15 seconds to a good deal higher. There’s reason to believe that humans in a “natural state” may have had reflexes of 0.12 or 0.10 seconds. This is about the same as a similar sized animal’s reflexes, and this speed is just about the hard limit of the nervous system. You have to wonder why reflexes would be slow at all, and why our reflexes aren’t as fast as our nerves can go all the time?

This article is a work in progress! Check back soon for more info, and sources for all this data.

More info we want to add soon

details on reaction time (bring in that native american study and the canine study)
details on other hormones if known
details on skull (length, jaw, palate and maxilla), height, robusticity (elbow width)
frequency of Minor Physical Abnormalities?
hypothalamus (navigation)
iris contraction? achilles tendon relaxation speed
incidence of balding
incidence of myopia
Insights from the book The Shallows – creativity, focus, open-mindedness, friendliness (to strangers), independence

Show some differences in living conditions – EMF, lifestyle+philosophy, diet both good and bad, disease eradication, exercise, light source, pollution

Does PUFA lower testosterone?

I found testosterone data for many of the countries in the world, and I correlated this with total PUFA consumption for those countries.

Low testosterone countries have high PUFA diets

There seems to be a strong correlation. High PUFA countries have less testosterone.

This is Omega 3 and Omega 6 PUFA combined. Most countries with high Omega 6 diets had low testosterone, but I saw several that had low Omega 6 diets and still had low testosterone. But what many of these countries did have was high Omega 3 diets. This suggests that Omega 3 is linked to low testosterone too, not just Omega 6.

Another study found a correlation between the ratio of PUFA to Saturated Fat in a person’s diet and their testosterone.

High PUFA diet correlates with lower testosterone

Chart adapted from here (link). As you can see, lots of PUFA but not much saturated fat means low testosterone, according to this study. The more PUFA, the lower the testosterone.

Seed oils are in many snacks, but they don’t have to be! If you’re interested in potato chips fried in tallow, not seed oil, check these out. Click the horse to visit

Go here to get tallow fried potato chips
Click the horse to get the potato chips! (Clicking opens )


This is my first draft. I plan to post the raw data here, and to improve the “PUFA in diet” scale on the chart of the countries, which in the current version is not done very well (mixed units, and no units visible on the chart). I’m getting the PUFA data from this study. (Link)

Check back for updates! Also take a look at our other articles about testosterone, listed on our homepage.


Pesticides May Lower Testosterone

Here is a chart of agricultural chemical (like pesticides) use by country, compared to testosterone in that country. There seems to be a strong relationship! Testosterone is much lower in the countries that use a lot of agricultural chemicals.

This chart suggests that testosterone drops with increased pesticide use.

This might help explain the very severe and mysterious drop in testosterone in most but not all parts of the world since about 1980. The other connection I’ve identified is PUFA consumption from the rise in seed oils in people’s diets around the world.

Here’s a chart that shows that places in the USA with many cornfields nearby generally have low testosterone. The few places in the USA that have testosterone that isn’t too low, generally don’t have cornfields nearby.

[11/16/23 – chart is out of date, the lowest numbers aren’t quite so low for one thing]

Testosterone is lower near cornfields. Atrazine lowers testosterone.

Some of the locations on the map have many crop fields nearby, but testosterone wasn’t as low. Hay fields and wheat fields don’t correlate so well with low testosterone. But when we focused on cornfields or soybean fields we found this pretty strong correlation. We think that some of this may be the result of the pesticide atrazine, which is used mostly on corn and not so much on other crops. (Source)

Here is a map of testosterone in the USA. (Using the same data as the chart above) You can see that the corn-growing midwest is especially low.

Testosterone levels across the USA map

You can start to protect yourself from pesticides lowering your testosterone by filtering your water. Pesticides get into water runoff from farm fields, and from there into the water supply. It’s probably worse if you live in an agricultural area.

There’s a comprehensive article on the best water filters to remove pesticides that lower testosterone at this website:

Pesticides may lower testosterone. Before pesticides, men's testosterone levels were much higher.
110 years ago before pesticides, they naturally had better hormone levels.

Another way that pesticides can get into your body is on your food. This organization does a great job identifying which fruits and vegetables have the worst levels of pesticides –

You should consider growing these plants on your own, or buying them from a farmer’s market or at least certified organic.

Russia, Central Asia, Pesticides, and Testosterone

Central Asia raises some questions about the link between pesticides and low testosterone. As far as I can tell from a quick look, the situation is as follows:

All regions of Central Asia studied had high testosterone a few decades ago. At this time, Kazakhstan grew grain, and the rest of Central Asia grew other products, but perhaps not as much since these places are more arid or mountainous.

In the current day, most of Central Asia has kept its high testosterone, but the studied regions of Kazakhstan now have very low testosterone.

Perhaps the low testosterone seen in Kazakhstan is due to the long term, multi-generational effects of pesticide exposure from grain production some decades ago, even though those people at the time had high testosterone.

According to this report, all Central Asian nations have areas heavily contaminated with pesticides. It would be a problem for our theory if the Central Asian nations other than Kazakhstan have just as high pesticide contamination as Kazakhstan. My guess is that wide areas of northern Kazakhstan are contaminated, while only localized parts of the other Central Asian nations are contaminated. But that is a guess that I haven’t confirmed yet.

Another big issue for the theory is that some parts of Russia with high grain production also have high testosterone, specifically Stavropol and Kurgan. It seems that the people in Stavropol could be exposed to much the same amount of wheat pesticide as the people in Kazakhstan, so why would they have such different hormone levels?

This area needs further study!


What else lowers testosterone?

Another potential cause of low testosterone is the seed oil found in junk food. We have an article about that here. And if you’re interested in snacks made without seed oil, check out our potato chips made with tallow, and no seed oil!

They’re available at and you can click the horse in the image to visit that page.

Go here to get tallow fried potato chips
Click the horse to get the potato chips! (Clicking opens )

Do Hunter Gatherers Have High Testosterone?

Many of them do, but some don’t. (Article may need some updating – 11/30/23)

Testosterone in the Kalahari Desert

The !Kung San people live around the Kalahari desert in Southern Africa. Studies on their testosterone level show that it is not particularly high.

!Kung San people (hunter gatherers) – 473 ng/dl. Average age of these men was 26.5. The study was done around 1987. Source: (1)

For comparison, the nearby Kavango people (cattle herders and plant growers, not hunter-gatherers) – 603 ng/dl. Source: (1)

In another study in 1986, the !Kung San people’s average testosterone was 534 ng/dl before the hunt, and 544 ng/dl after the hunt. Source: (2)

In an earlier study from around 1975, the !Kung San people’s average testosterone was about 560 ng/dl (estimated). Source: (3)


In many of the developed countries at the time of these studies, testosterone was quite a bit higher in this age group than the testosterone of the hunter-gatherers.

Around 1987, in the USA, probably in Richmond, Virginia, men age 22-25 had 802 ng/dl testosterone.

Around 1987, in the USA, probably in Seattle, Washington state, men with an average age of 27.3 had about 545 ng/dl testosterone.

Around 1986, in Finland, men age 24-30 had 707 ng/dl testosterone.

However, Testosterone among young men in the developed world today is generally lower than that of these hunter gatherers, because testosterone in the West and in East Asia has declined greatly since about 1980.

Nomadic Herdsmen with Very High Testosterone

Although not hunter-gatherers, the Turkana people of Kenya are also of interest. Traditionally, they are nomadic pastoralists mostly relying on milk and meat from their livestock.

In 1992, Turkana people living as nomadic pastoralists – 943 ng/dl at a mean age of 45.4

In 1993, Turkana people who have given up nomadic life for a settled agricultural life – 675 ng/dl at a mean age of 43.5.

Testosterone usually drops with age. If the Turkana have the same rate of testosterone decline with age as Americans do, which is likely, then we can guess what testosterone levels would be in Turkana men in their 20’s. For a group of men with an average age of 45 to have a testosterone level of 943 ng/dl, one would expect that the members of the group in their early 20’s would have a testosterone level of something like 1107 ng/dl.

And according to the study, the nomadic Turkana had their blood collected in the summer at a time when they were pretty low on food, in a calorie deficit, which will generally lower testosterone. So you could guess that the Turkana when well-fed would have even higher testosterone.

Another interesting thing is that the nomadic Turkana had outliers with such high testosterone that it would probably flag a steroid test! 14% of the nomadic Turkana men were over 1500 ng/dl, two of them were over 2000 ng/dl, and the highest result was 2663 ng/dl. Impressive!

Source: (4)

Papua New Guinea Testosterone Levels

Testosterone levels are known from hunter-gatherer groups in Papua New Guinea. All of these are men in their early 20’s. The first three studies were done around 1983-1984.

Amele people – 667 ng/dl

Bundi people in their native highlands – 950 ng/dl

Bundi people having moved into more settled areas and not living a hunter gatherer life anymore – 686 ng/dl

Hagahai people from the highlands – 307 ng/dl – this group was first contacted in 1983. The info was published in 1993, but I don’t know when the testing was done. I think it may have been pretty soon after contact. This group was so malnourished that their growth was stunted and puberty was delayed into the late teens. This malnourishment is surely why testosterone was so very low.

Sources: (5) (6)

Testosterone in the Amazon jungle

In Brazil in 1982, the hunter gatherers living in the jungle had pretty high testosterone. Here’s the averages of five different tribes that were studied:

  • Surui – 891 ng/dl
  • Xikrin – 745 ng/dl
  • Paracana 1 – 690 ng/dl
  • Paracana 2 – 671 ng/dl
  • Paracategê – 608 ng/dl

At the time of that study, urban Brazillians (Caucasian) in Sao Paulo had testosterone of 591 ng/dl.

According to the study (translated into English), “The Paracategê or Gaviões do Oeste ou da Mata are members of a Timbira tribe, from the linguistic family Jê, located in the Mãe Maria reserve, approximately 35km from the city of Marabá, in the southeast of the State of Pará. […] We assume that the average testosterone of the Paracategê was close to the average of the Caucasoids and moved away from the averages of other forestry groups by greater degree of acculturation, due to the greater proximity to the city, due to the fact that the village is located close to the highway state, use motorized vehicles, get supplies in supermarkets, coming closer than other groups to the urbanized civilized way of life.”

So apparently the tribes that were living the hunter gatherer life more, had higher testosterone than the tribe that wasn’t.

Source: (7)

There’s background info on these tribes at

Some other studies

There are a few more studies that I could find. However, they use saliva rather than blood to measure testosterone, which is not as accurate, and it is debatable how this can be compared with blood (serum or plasma) testosterone. Even so, they show lower levels in these people than in Americans at the time.

Translated into blood ng/dl terms, the testosterone of these people was somewhere around these numbers:

1993 – Lese people, plant-growers from Ituri forest (jungle), Congo: 499

1996 Tamang people, mixed plant-growing and animal herding, from central Nepal: 447

1996 Ache people, hunter-gatherers (mostly hunting) from southern Paraguay: 373


The highest testosterone of these groups was found in the nomadic pastoralists, and it is very high. It is among the highest results I’ve found in hundreds of studies around the world. It’s interesting that the members of this group that stopped being pastoralists and lived a settled life had notably lower testosterone than the pastoralists!

Next, the testosterone in Papua New Guinea hunter-gatherers was very high as well, as long as the people were well-nourished. It seems that testosterone was also lower in the people who stopped living the hunter-gatherer lifestyle as well. In New Guinea, the downside of a hunter-gatherer lifestyle was also seen – when food is scarce, people suffer. The malnourished tribe had very low testosterone.

The testosterone in the Amazon jungle was quite high, and again, it seemed that being a hunter gatherer produced higher testosterone than the levels in a tribe that was moving away from the hunter gatherer life.

The testosterone among the !Kung San in Africa was not high. I don’t know what explains this.

Testosterone was also not high in the Lese people of the Congo jungle.

And testosterone was quite low in the Paraguay hunter-gatherers.

All in all, these lifestyles seem to produce high testosterone as long as there isn’t major malnutrition and starvation.

Why Do Hunter-Gatherers Have High Testosterone?

These groups get a lot of exposure to daylight and the natural circadian rhythm of life. Bright light keeps testosterone high.

They are much less exposed to endocrine disrupting chemicals, especially pesticides. These chemicals lower testosterone.

They don’t eat our seed oil filled junk food. The amount of polyunsaturated fat they eat is usually pretty low. PUFA, especially from junk seed oil, probably osterone.

Preserving Natural Testosterone In An Industrial World

To avoid these modern industrial things that are lowering your testosterone, you can:

We’ve got potato chips fried in tallow, not seed oil, if you are interested. Tallow is paleo, and potatoes were eaten by many tribal people. There are no additives in our potato chips. The chips can be found at

Go here to get tallow fried potato chips
Click the horse to get the potato chips! (Clicking opens )

What Lowers Testosterone?

Testosterone is falling all around the world. This hormone is critical for health and vitality. In this article you will find out what lowers testosterone.

Endocrine disruptors bad diet and stress will all harmfully lower testosterone
Click for full size

This article is a work in progress, check back often!

“Endocrine disruptors” and “Xenoestrogens”

All kinds of garbage chemicals float around messing up your hormone system. This site will explore how to block them all and keep yourself healthy and strong!

Endocrine disruptors damage your hormones - at we help you block them
Block those endocrine disruptors and save your family’s hormones!

  • Water filters for your drinking and shower water both.
  • No plastic shower curtain off-gassing damaging chemical fumes. Get a glass door instead. No problem!
  • Organic food with no seed oil in it, note that you can still eat “junk” snacks such as potato chips as long as they’re free of chemicals and seed oils, which makes them not junk anymore!
  • Soaps and shampoos without bad chemicals, such as this shampoo/body-wash combo – we’ll post a guide to this soon.
  • Cosmetics and lotions – there will be a guide to this too.
  • Cookware with no chemical coatings (or exposed aluminum), glass bottles instead of plastic.
  • Clothes, bedding, and furniture made with natural fibers and no chemicals. Artificial fibers like polyester may lower testosterone.
  • Dishwasher and laundry detergents that won’t damage your health and hormones. The best we are aware of is from Dapple Baby. They make certified glyphosate-free products, from the least chemically weird stuff.

Dishwasher Detergent Pacs by Dapple Baby, 25 Count Pouch

If you want in-depth info on all the things that lower testosterone and what to do about it, then read on!

Agricultural Chemicals like Pesticides

Countries that use a lot of agricultural chemicals seem to have much lower testosterone than those that don’t. The correlation appears pretty strong.

More information here:

You can prevent a lot of agricultural chemical exposure by

1) Not living or working near “industrial agriculture.”

2) Eating food raised without chemicals.

3) Filtering pesticides out of your water, especially if you live near industrial agriculture. Pesticides seep into the water from farm fields and end up in your body.

What job has the highest testosterone levels?

In the USA, for 2013-2014, here are the average testosterone levels for different occupations, industries, and hours worked. (Job data doesn’t seem to be available for 2015-2016.)

Here’s testosterone for the different occupations, and below is testosterone for the different industries. The average testosterone for all the USA data in 2013-2014 was 462 ng/dl, so you can use that for comparison.

Here’s testosterone for the different industries.

I was wondering about the results from the arts, entertainment, recreation industry so I checked into them. A lot of the datapoints in that group were for those whose occupation was something not particularly related to arts or entertainment, such as transportation or maintenance occupations, despite being in that industry. There were only two datapoints in this industry that also had the “Arts, Design, Entertainment, Sports, Media” occupation, and these two datapoints were 486 and 285, averaging 386. Not so high as that original 505 for the broader industry.

I also looked at the sales occupation in more depth. Several of the industries contained those whose occupation was sales. Here are the testosterone levels of the sales workers in each industry.

  1. Manufacturing: Non-Durable Goods (two guys) = 598 (avg of 736 and 459)
  2. Professional, Technical Services (four guys) = 565
  3. Real Estate, Rental, Leasing (five guys) = 562
  4. Industry: Other Services (one guy) = 549
  5. Accommodation, Food Services (one guy) = 531
  6. Retail Trade = 468
  7. Finance, Insurance = 381
  8. Wholesale Trade = 374
  9. Manufacturing: Durable Good (three guys) = 313 (average of 379, 302, 258)
  10. Construction (one guy) = 268
  11. Information (two guys, they were 1290 and 333)

Here’s testosterone levels compared to number of hours worked.

Among those who worked zero hours, those who were under 65 had an average testosterone level of 480. (The average for all under 65 was 473) And among the zero hour workers, excluding those who said they aren’t working because of heath or disability, and excluding those over 65, the average testosterone level is 490. But the zero hour workers (of any age over 18) who said their main reason for not working last week was “Taking care of house or family” were 435 ng/dl testosterone.

Here’s testosterone levels for each type of employer, private, government, self-employed, etc.

Testosterone levels for government workers, self-employed, etc

Remember, the average of all the USA data (over 18, male) was 462 for 2013-2014.

Does education lower testosterone?

In 2013 – 2014, in the USA, among males over 18:

  • College graduates and higher were 445 ng/dl.
  • Those who’d only completed “some college” or an associate degree were 446 ng/dl.
  • Those who were only high school graduates were 483 ng/dl.
  • Those who didn’t have a high school degree but had completed 9-12th grade were 458 ng/dl.
  • Those who had only completed something less than 9th grade were 473 ng/dl.

So basically, any kind of college seems to go along with slightly less testosterone, but it’s not a big effect on average, and there were both high and low testosterone datapoints in all the groups.

However, when you include BMI (whether a person is overweight or not), it looks like education may sometimes go along with higher testosterone in those who are not overweight (BMI under 25), as you can see from this chart.

The chart also shows that race/ethnicity is involved too.


More questions I plan to answer in this article soon (this is a draft):

Are smart people higher or lower testosterone?

Do soldiers have higher testosterone?

What about religiosity? (israel, palestine, also i can compare secular students to madrassa students)

Has testosterone always decreased with age? (actually, put that in test 100 years ago)

Same with “has test fallen in the lean and healthy too?”

In the 2015-2016 USA data I didn’t see any noticeable correlation between testosterone and family size.

I saw no serious correlation of testosterone and height across all the data.

Testosterone and BMI, 2015-2016, USA, 18+

Very strong correlation.

  • BMI 16-17.5 (only 6 guys): 618 ng/dl (For a 5’10” man, that would be 112-122 lb bodyweight)
  • BMI 17.5-18.5: 796 ng/dl (A 5’10” man would be 122-129 lb)
  • 18.5-20.5: 623 (5’10 = 129-143 lb)
  • 20.5-22.5: 577 (5’10 = 143-157 lb)
  • 22.5-24.9: 571 (5’10 = 157-174 lb)
  • 25.0-26.5: 472 (5’10 = 174-185 lb)
  • 26.5-28.5: 450 (5’10 = 185-199 lb)
  • 28.5-29.9: 418 (5’10 = 199-209 lb)
  • 30-35: 395 (5’10 = 209-244 lb)
  • 35-40: 338 (5’10 = 244-279 lb)
  • 40-45: 317 (5’10 = 279-314 lb)
  • 45 and over: 283 (5’10 = over 314 lb)

The CDC considers under 18.5 BMI to be underweight, 18.5-24.9 to be normal weight, 25-29.9 to be overweight, and 30+ to be obese. The average testosterone of everyone who was lower than 25 BMI (everyone who wasn’t overweight) was 589 ng/dl.

I was surprised that testosterone kept going up with lower BMI even when the BMI was already low enough, even into the underweight range. Perhaps these guys were hyperthyroid? (that’s linked to high testosterone). Whatever the reason, I don’t advise being underweight or losing weight to get down into the underweight range.

Testosterone and race/ethnicity

In 2015-2016 USA, among all males 18 and over

  • Non-Hispanic Asian: 496
  • Non-Hispanic Black: 489
  • Other Race – Including Multi-Racial: 481
  • Mexican American: 449
  • Non-Hispanic White: 446
  • Other Hispanic: 424

Among all non-overweight (under 25 BMI) males 18 and over,  however, average testosterone was 589 ng/dl, and among these non-overweight males:

  • Non-Hispanic Black: 678
  • Other Race – Including Multi-Racial: 642
  • Mexican American: 584
  • Non-Hispanic White: 578
  • Non-Hispanic Asian: 545
  • Other Hispanic: 511

Controlling for education levels, things are interesting:

Controlling for prescription meds:


Testosterone and age, 2015-2016

Everybody (all BMI)

  • 20-24: 535
  • 25-29: 556
  • 30-34: 461
  • 35-39: 466
  • 40-44: 465
  • 45-49: 430
  • 50-54: 480
  • 55-59: 441
  • 60-64: 433
  • 65-69: 454
  • 70-74: 375
  • 75-80: 388

What I notice here is that Americans currently have a big drop off in testosterone after 30. It’s interesting that I see no such drop off in a lot of data from the past. I think this suggests that something in the American environment now is lowering testosterone and that after 30, the body has lost some of its ability to fight against whatever this is.

Everybody with under 25 BMI (normal BMI)

  • 20-24: 681
  • 25-29: 668
  • 30-34: 584
  • 35-39: 621
  • 40-44: 677
  • 45-49: 570
  • 50-54: 679
  • 55-59: 584
  • 60-64: 529
  • 65-69: 480
  • 70-74: 488
  • 75-80: 464

Again, the average testosterone of all those with BMI under 25 was 589 ng/dl.

Testosterone and household income

In the 2015-2016 USA data I saw no noticeable correlation between testosterone and household income either. Perhaps the levels over 55k were a bit lower than under 55k but it’s not clear.

100k+ = 446
75-100k = 461
65k-75k = 436
55-65k = 409
45-55k = 470
35-45k = 454
25-35k = 488
20-25k = 455
15-20k = 450
10-15k = 477
5-10k = 467
0-5k = 446
Code 0 = 547 (average age of that was 43, so not particularly skewed by too many young guys)
wait so what is code zero


Is testosterone higher in the city or in the country?

Hunter Gatherers and other tribal groups

Testosterone is higher in traditional tribal groups than in the same tribal groups settled.

Turkana nomadic pastoralists: 943 (mean age 45.4)

Turkana settled agriculture: 675 (mean age 43.5)

Bundi hunter-gatherers: 950 (age: early 20’s)

Bundi urban: 686 (age: early 20’s)

Average of four South American hunter-gatherer tribes (Surui, Xikrin, Paracana 1 &2): 749 (full age range I think)

South American tribe (Paracategê ) with a somewhat more modernized life (lived near the highway, got supplies from supermarkets): 608 (full age range I think)

(more info, with sources, here)

South Africa, from the most rural to the fully westernized suburban

South Africa 1981 – age 60-73: Ethnic Africans living in “a rural area of the Transkei” – eating traditional diet – 606 ng/dl. Dropped to 472 after three weeks living in a hotel eating the Western diet. (source)

But then, also in South Africa, age 20-82, from 1996-1998, adjusted for age and BMI by the study, and excluding those taking medications and those with known diseases:

  • Living in tribal areas/ “rural village” – 525 (original raw data was 493 at age 45.8)
  • Living (working) on commercial farms / “farm workers” – 460 (original raw data was 486 at 36.1)
  • “Squatter camps” or “informal settlements” – 435 (original raw was 467 at 31.8)
  • “Living in established townships w/ full access to water & electricity” / “urban townships” – 530 (original raw was 524 at 40.4)
  • “Fully westernized subjects living in western-type houses in upper class suburbs” / “urban affluent” – 595 (original raw was 623 at 33.2)

(Ethnicity was not specified.)


However, another datapoint from 2003, “rural-dwelling southern African subjects of predominantly Swazi and Shangaan extraction” are the highest of all though. 808 in non iron poisoned, at mean age 52. (lower in those iron-poisoned) (source)

So South Africa looks like a U-shaped curve, testosterone is high in the very rural tribal (as long as they aren’t diseased or poisoned by some lifestyle factor or have parasites), and it is high in the upper class, fully westernized people. But testosterone is low in the favela type situation.


(The stuff below is a draft for future writing.)

Nigeria urbanization

I can get some stuff from modern Nigeria too. It looks like urbanization is lowering them.

Iran, urban vs rural

Urban near Arak, Iran – 612 ng/dl, Rural near Arak, Iran – 661 ng/dl. (source)

Iran, urban vs rural. (I have several really, Amirkola?)


Finland old rural


US modern pesticide midwest, but note that my big city results are consistently low. Discuss how midwest went from higher to lower:

US farmers – black NC, and also from current NHANES.

Boston vs suburbs: (include Belmont from the past)

Pennsylvania – I can compare PSU, Hershey, Pittsburgh. Also I have Danville but don’t know the age (it’s prostate stuff so probably older) – although be aware it may not actually be Danville, that may be false info.

I’m able to compare some San Fran and LA neighborhoods.

I have Minnesota foresters I could compare to Rochester, MN. And also broader Olmsted county, but I don’t know about that one.


In Mexico, from October 2019 to February 2020, using salivary testosterone which is less reliable and we won’t try to compare it to blood testosterone results. All these guys were university students or workers.

Suburban: ~2.61 pg/ml (age 34, BMI 27.4)

Urban: ~2.76 pg/ml (age 24.7, BMI 24.2)

The suburban are a bit older and a good deal fatter than the urban sample, both of which will bring testosterone down, especially the difference in overweight-ness. To be honest, this probably accounts for the testosterone difference.


and i have some more mexico too

From a database

Surely I can find one of those databases to show urban vs rural, maybe a European one.

Brazil, Egypt, Thailand

I have for Brazil and for Egypt and maybe for Mexico and for Thailand, but it’s all pesticides, data from rural areas vs cities.


In March-May 1982, farmers from rural areas near Chengdu, China, were 718 ng/dl at a mean age of 46.3. (source) But in Shanghai (a big city) from January 1982 to June 1983, age 26-72, testosterone was 532 ng/dl. (source)


London is consistently lower,  and I have one from High Wycombe but don’t know age.


I have one from Ontaria suburbs, but I don’t have anything to compare it to.


Turkey probably has some


Sweden probably has some


Calorie deficit

One study looked at a bodybuilder doing an intense fat loss diet. During his 6 month diet, the bodybuilder’s testosterone dropped from 922 ng/dl to 225 ng/dl over the first three months, and remained in the low 200’s after the next three months as he continued to diet to get even leaner. When he stopped dieting, and began eating plenty of food again, his testosterone came back up.

Maybe not all diets will drop testosterone this drastically, but dieting certainly does tend to lower testosterone. Not good!

Low carbs

That low carb diet might be ruining your testosterone levels. (Source) It seems that the body wants plenty of food energy before it is willing to raise testosterone.

Without sufficient carbs, the body seems to consider itself to be in a starvation situation, as mentioned in this paper by Kyle Mamounis.

Not only does this carb-starved situation probably signal to the body that it can’t “afford” to produce testosterone, but low-carb also (initially) causes a corresponding rise in cortisol, which is a stress hormone that generally lowers testosterone.

So it’s not surprising to find that there’s a correlation between low testosterone and a high protein but low carb diet, which is the typical Paleo style diet with not a lot of carbs but plenty of meat and fish. Excessively high protein seems to lower testosterone too, which I will discuss further down.



PUFA is the type of fat found in seed oil like canola oil or soybean oil, the industrially produced fats used for making most processed foods. PUFA is also the type of fat found in Omega 3 supplements, which you may have been advised to consume by health gurus. You can read more about the possible dangers of Omega 3’s here:

Saturated fat is the major component of coconut oil and of animal product fat, like butter.

Studies suggest that countries that consume a lot of PUFA have low testosterone compared to low PUFA countries. (And this includes Omega 3’s, not just Omega 6’s.)

More info here:

The worst kind of PUFA is the PUFA found in vegetable oils, also known as seed oils. You can see that testosterone in America has dropped alongside the rise of seed oils.

Lowering testosterone isn’t the only bad effect of seed oils. Seed oils are involved with cancer, heart disease, obesity, and pretty much all the degenerative conditions that we struggle with today! To learn more about avoiding seed oils, you can check out

You don’t have to give up snacks to avoid seed oil. You might be interested in our potato chips fried in tallow, not seed oil, available at

Go here to get tallow fried potato chips
Click the horse to get the potato chips! (Clicking opens )

Physical Trauma (disease, surgery, infection, wounds, immediately after TBI)

Any acute trauma will drop testosterone very low and very fast. Testosterone levels seem to recover over about a week’s time. Traumatic Brain Injury, such as a concussion, has this short term effect, but also there is often lasting damage done to the brain, and testosterone does not rise all the way back up, even a year later. I wrote more about that below.

Intense physical stress

Ranger School, an intense military training school involving fasting, cold exposure, sleep deprivation, and intense exercise is an 8 week event that absolutely crashes testosterone. Testosterone drops from 499 ng/dl to 87 ng/dl, which is extremely low, and totally insufficient for male function. After Ranger School is over though, testosterone rises back up. (Source)

This illustrates why “hardcore” practices are likely to lower testosterone rather than raise it, contrary to what people often assume. Not many people are putting themselves through something as intense as Ranger School, but there are some that are taking cold showers, training very hard in the gym, fasting frequently, and maybe burning the candle at both ends to get more work done, and these people should know that this is probably dropping their testosterone considerably.

Since these things are often done under the impression that they are RAISING testosterone, this is a very important concept to know! Hardcore stress on the body tends to damage it. By itself, stress does not make you “stronger.”

Very often, to become stronger, we need to relax and have some leisure. Of course this is not a license to eat junk food and scroll social media all day. That will weaken you too.



Fasting lowered testosterone from 556 ng/dl to 391 ng/dl over an 83 hr fast. (about 3 and a half days without food)

Feeling Defeated

Animal studies suggest that if you accept defeat you will have lower testosterone. Keep your chin up, don’t give in!


Researchers found out that bright light increases testosterone. Depressed men had testosterone of 210 ng/dl, until they were exposed to a bright light box daily for 30 minutes soon after waking up. After two weeks of this, their testosterone rose to 360 ng/dl, which is a 71% increase, pretty impressive! They probably felt much, much better going from very low and insufficient testosterone up to 360 ng/dl, which is sufficient for at least a low level of male function.

Preferably you would get this bright light from going outside or sitting at a window, but if this is not possible for you, you can get a light box. The fluorescent light in the typical office is not really bright enough, believe it or not. In an office environment you ought to have a light box, or a lamp, or something to make it brighter where you are.

This light box has the same 10,000 lux brightness rating as the one used in the study:

Verilux HappyLight Luxe – UV-Free LED Therapy Lamp, Bright White Light with 10,000 Lux

I have one like this and I like it a lot. I usually feel better when I use it.

Bad sleep

Consistent sleep loss has been seen to lower testosterone quite a bit. One study suggests that late bedtimes are worse for testosterone than early waking is.

TBI long term effects

Testosterone was measured following traumatic brain injury. Testosterone drops very far right after TBI, but then it partially recovers. Unfortunately it often does not fully recover. Possibly this is because the parts of the nervous system that regulate testosterone production have been damaged.

One severe TBI could do the damage, or several more mild TBI’s. However, even just one mild TBI could do it sometimes.

It is probably wise to avoid hard sparring in boxing, and the causes of traffic accidents.

Sadly, veterans often have TBI’s from the blast wave of nearby explosions.

There are other sources of brain injury than TBI, such as infection, and the long term effects of long-lasting depression, actually.

I believe that extreme “headbanging” can either cause or exacerbate TBI over the long term.

Brain injuries can be somewhat healed over time. Supplying the brain with energy by eating plenty of carbs, and reducing inappropriate inflammation by avoiding excess iron, alcohol, and PUFA are all good ideas. Lots of deep sleep is valuable.

“Red light” exposure on the head and pregnenolone could help facilitate brain healing. Pregnenolone is a precursor hormone which is found to increase the levels of allopregnanolone in the brain, a neuroprotective substance that helps the brain heal, and which is being studied as a way to reverse depression.

Psychological Stress

Distress is not good for your hormones!

Psychological stress suppresses levels of circulating plasma testosterone.”

Low fat

Does a low fat diet = Low testosterone body? This study thinks so.

Excess protein

Apparently too much protein is correlated with low testosterone. I’m not sure why. Here are some studies related to this:

Testosterone and cortisol in relationship to dietary nutrients

Diet-hormone interactions: protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone

Nutrition-endocrine interactions: induction of reciprocal changes in the delta 4-5 alpha-reduction of testosterone

Deficient Zinc

A zinc deficiency is associated with lower testosterone.

Deficient Copper (but don’t be excessive either)

Supplementing high levels of zinc without a corresponding amount of copper will deplete your body’s copper supply, which has been seen to cause low testosterone. Supplements which contain a bit of copper as well as zinc are therefore better than those that contain only zinc. However, it is important to not consume excessive copper either, because this is harmful.

Excess Iron

Watch out for food products with excessive added iron!

Overtraining (weights or aerobic)

Excessive demands on your body seem to cause low testosterone. This is called “Exercise Hypogonadal Male Condition.” Many people lift weights to increase testosterone, but there is a serious risk of going too hard and actually lowering testosterone. It may actually be the norm among serious lifters. It is probably for this reason that one study found elite powerlifters have quite low testosterone. Runners and other endurance athletes frequently have lowered testosterone as well.


Health books and websites rarely mention it, but alcohol is quite bad for you. It seems that it probably lowers testosterone. One study from Gangtok, India found much lower testosterone in alcoholics than other people. Normal men had 756 ng/dl testosterone, while alcoholics had 496 ng/dl. This is a 34% decrease.

RF Exposure and possibly EMF exposure (phones, electric razors, laptops, offices, cities)

One study exposed rats to a cell phone making a call for an hour daily for three months. The rats’ testosterone dropped 51% from 634 ng/dl to 310 ng/dl. (Source) I’m not clear right now how this applies to humans, but it’s concerning.

Another study had similar results.

I strongly suggest turning off your cell phone, and turning off wifi in your house and using ethernet cables instead. The strongest sources of RF exposure in a typical person’s life are probably the cell phone in your pocket and the computer in front of you. My phone was constantly transmitting, and transmitting powerfully too. You can carry your phone turned off and you will be exposed to far, far less RF and EMF. Putting it on airplane mode will greatly diminish the RF, but not the EMF, which is certainly a huge improvement, and if you’re not willing to turn off your phone you can do that instead. Some people say that turning your phone off isn’t enough, but as far as I’ve seen, my phone basically stops transmitting detectable RF and EMF when it’s off.

Next, connect your computer to your router with ethernet cable so that you can turn your computer’s WiFi off (this is the important part). The router itself is not that powerful when you’re pretty far away from it, although I still suggest turning it off. It’s your computer that you sit next to that is really transmitting the powerful waves that could harm you, because you are so close to it.

If you have any other wireless devices, like wireless headphones, or any smart devices, I would really suggest turning them off and not using them. Cordless phones probably transmit RF, likely from the “base station.” I found that the base station was constantly transmitting, all day and all night. I put the base station far away from the part of the house that I spend time in, and that seems to have brought the RF exposure way down, which I’m fine with, since it’s basically impossible to cut RF exposure down to nothing unless you intend to live inside a Faraday cage, or somewhere very remote!

The radio waves from cell towers are far less powerful than the radio waves from the devices right near you.

I haven’t investigated it in depth, but as far as I can tell, EMF from power lines is not really a concern.

If you want to check RF and EMF for yourself, you can get the TriField TF2 detector, which seems to work really well, and I’ve really enjoyed using.

TriField EMF Meter TF2


Disturbingly, some food is contaminated with substances called mycotoxins produced by mold. Mycotoxins seem to lower testosterone quite a bit.

Updates on the Effect of Mycotoxins on Male Reproductive Efficiency in Mammals

It seems that grains are one of the big culprits for mycotoxins, either eaten directly, or when fed to an animal which is then used for meat or milk. Spices, nuts, beer, and wine can also be contaminated. Moldy fruits and vegetables should never be eaten. It may be that people respond well to grain-free diets because of the reduction in mycotoxin exposure. It may also be a benefit of pasture-raised meat and dairy that these animals are exposed to less mycotoxins than grain-fed animals. Mycotoxin contamination is a serious problem in animal feed.

Another source of mycotoxins is contaminated herbal supplements. Mycotoxins can also be produced in moldy buildings.

I don’t currently know how much of an impact mycotoxins have in a normal person’s diet, but it may be a factor to keep in mind.


Being cold is not good for your testosterone. A brisk cold shower might be a fine idea if it’s quick, but long term cold exposure is definitely not a good thing.

Pituitary-gonadal response to extreme cold exposure in healthy men

Indoor Chlorinated Pools

One study found that testosterone was lower in teenagers who had spent lots of time in indoor chlorine pools as young children. Outdoor pools were fine however.


Constant exposure to noise is not only aggravating, it actually lowers testosterone too! (Source)


Various types of plastic and other pollutants have some testosterone-lowering abilities. I suspect that agricultural chemicals and maybe plastics are the worst though. “Classic” pollution from factories and mines and such may not have too great an effect on testosterone. Russian industrial areas generally have high testosterone. These are probably highly polluted places. The Soviet Union is said to have paid no attention to pollution controls, so the people in these regions have probably been exposed to industrial pollution for a long while, and yet their testosterone is much higher than testosterone in the USA, which has controlled industrial pollution. Strangely, testosterone was higher in the USA in the past, when there was probably more industrial pollution. That does not mean that pollution raises testosterone, but it does suggest that pollution from industry is not the main factor causing the huge testosterone decline in much of the world since approximately 1980. More supporting data: Mechanics in Nigeria, exposed to large amounts of pollutants, have very high testosterone. But of course, some polluted areas do have low testosterone. China has pretty low testosterone in its young people today, and it is apparently quite polluted. But there may be other reasons for this.

Nuclear Radiation from Testing

Kazakhstan has very low testosterone and a very high rate of urological issues, which is strange since much of the rest of central Asia has high testosterone. Maybe it is because the Soviet Union used northeast Kazakhstan for testing many nukes over the years.

Similarly Belarus and Ukraine appear to have quite low testosterone. These are the countries that are closest to the Chernobyl accident of 1986. I have data from some of these areas from before 1986 and testosterone is high!

Japan’s testosterone is also pretty low. Maybe this is the long term effect of radiation from Hiroshima and Nagasaki?

Unfortunately I don’t have testosterone data from Nevada where the USA tested many nukes.

None of this is proof that relatively low level nuclear radiation exposure causes low testosterone, but it is an interesting theory to be considered.

Apparently, just about everyone in the world has been exposed to low but measurable amounts of nuclear radiation from nuclear testing over the last few generations. Maybe this also contributes to the strange decline in testosterone around the world.

Polyester clothes

It’s conceivable that polyester underwear may decrease testosterone production, according to this study. I haven’t investigated it further.

Headphones and music

Strangely enough, listening to music appears to lower testosterone. I don’t know if the effect is really significant or not. I doubt it matters if you listen to a moderate amount of music. But the effect might become significant if you listen to music all day, like many do. I don’t know whether this produces a consistently lowered testosterone or not.

I also suspect that the EMF from headphones might disrupt the brain, which among other things could lower testosterone. I can’t prove this hypothesis right now.

Either way, I believe I have felt better avoiding constantly listening to music, on my headphones.

Does high altitude increase testosterone?

Apparently being in the mountains might raise your testosterone! But maybe not for a good reason.

Does high altitude increase testosterone? In this study, testosterone rose about 300 ng/dl at the high altitude of 14,115 ft on Pikes Peak, Colorado

In this study (source), healthy, fit men between age 18 and 35 were sent from Palo Alto, California straight to the top of Pikes Peak in Colorado the next day! There they lived in a research lab at the summit, which is 14,115 ft above sea level. Their testosterone rapidly increased from the low 700’s ng/dl to between 900 and a little over 1000. Testosterone stayed this high the whole time they were at altitude.  It should be noted that these men were selected to be quite fit, so they were probably not gasping for air too much at this altitude. They were also made to eat enough to maintain their body weight, which is apparently hard to do at altitude.

Another study also shows an increase in testosterone at a more moderate altitude of about 6560 ft, which is just a bit higher than Colorado Springs.

Why does this happen?

As I understand it, this is what happens. Testosterone increases during acute exposure to the oxygen-deprived air of high altitude as your body attempts to get you enough oxygen. But this state of things goes along with “excessive erythrocytosis” and chronic mountain sickness. Natives of high altitude places, that have lived there for many generations, mostly have unusually low testosterone, because their bodies have adapted to the high altitude, such that they no longer have erythrocytosis and mountain sickness. But this adaptation involves testosterone going lower. The ones that do have high testosterone still, are the ones that aren’t yet adapted to high altitude, and still have erythrocytosis. The researcher Gustavo F. Gonzalez explains all this.

In Peru, at high altitude, testosterone levels can be quite low among the native people who are adapted to it. In Puno, Peru, testosterone was 220 ng/dl. (source). (Not all the results from Peru were this low however.)

In Azerbaijan, in the “Karabakh highlands” among natives of high altitude villages, testosterone was 313 ng/dl, in 1988 which is very low. (source)

In Kyrgyzstan, among natives of these mountain villages aged 18-55, at 1200m testosterone was 448 ng/dl, at 2300m testosterone was 452 ng/dl, and at 3600m testosterone was 169 ng/dl, very low. (source) However, in the city of Bishkek, Kyrgyzstan (altitude just 800m), among 20 year old wrestlers and judokas, testosterone was 738 ng/dl. (source)

In Tajikistan, in the Pamir mountains among native Tajik people, in 1986, testosterone was 535 ng/dl at 2000m altitude, 500 ng/dl at 3000m, and 465 ng/dl at 3640m. (source) At the time and the place, this wasn’t very high testosterone for Central Asia.

In Bolivia, in those who aren’t adapted to the high altitude and have excessive erythrocytosis, testosterone is high – 714 ng/dl at age 44. (source)

However in Tibet, among the native Tibetans, testosterone is OK, being 623 ng/dl at age 21. (source)

Very low altitude decreases testosterone

Strangely, living about 984 ft BELOW sea level seems to decrease testosterone. (Source)

So does high altitude increase testosterone in reality?

It should be noted that other studies, such as this one, have found the opposite, that high altitude decreases testosterone. Another study found no significant change either way.

Possible reasons for these conflicting results:

  1. Some studies  are done on mountain climbers. This level of exertion will lower testosterone a lot.
  2. Altitude tends to make people eat much less, along with increasing the calorie requirements, and a calorie deficit like this will decrease testosterone. The Pikes Peak study above found this effect as well. The men who increased testosterone were specifically made to eat enough to maintain their weight.

What about Colorado?

We do have data from somewhat lower parts of Colorado, showing that testosterone there is not noticeably higher than the rest of the USA. Although it is a bit higher than its neighbor Kansas. Most US states have dismally low testosterone levels on average due to the strange drop in testosterone over the decades, around the world. (We blame diet and endocrine disruptor chemical pollution) You can see our article on testosterone in US states for more info and for the Colorado testosterone data.

Testosterone Levels 100 Years Ago

Please note that some of this data is a bit doubtful. However, we are still publishing this info out of interest.

Many articles say that average testosterone has been rapidly falling recently. But most of these articles don’t show you any actual numbers. Even studies of testosterone’s decline usually only show data from the 90’s or so. While there is currently no way to really know what testosterone was 100 years ago, I have discovered real data on testosterone from 1962 to the present day, and I have found some ways to estimate what testosterone was a few hundred years ago too. Finally, I have found a study of testosterone in hair from almost 2000 years ago in Egypt!

Testosterone Levels 60 Years Ago

The testosterone trend in the USA from 1960 to 2023

As you can see, testosterone has fallen a lot in the USA since about 1985 to today. Testosterone from 1962 until about 1985 was a lot higher than today. It isn’t clear whether testosterone was higher in the 60’s than in the 70’s though. While I did find quite a few studies from this time period, I was not able to find what time of day and what age group many of the 60’s and 70’s studies were done with. Without the age group, I couldn’t correct for age. The time of day is important because testosterone is now usually measured around 8AM in the morning, since testosterone falls throughout the day, and then rises again through the night. They didn’t really know about this when they were doing the early testosterone studies, and I think it’s likely that many of these studies were done a good deal later than 8AM, thus providing lower results than the “morning testosterone” level that we use today and that we are comparing with. For these reasons, I have primarily stuck to data that came from morning measurements, or in just a few cases, I’ve corrected data to reflect a morning measurement.

As you can see, average testosterone in the USA was something like 625 ng/dl in the 70’s, until the early 80’s. This is reasonably high testosterone. But since then it has been falling steadily.

In 1985-1986, among a large, probably nation-wide sample of veterans, done by the CDC, testosterone at age 31-49 was 640 ng/dl. (source) To make that data representative of all the adult men in the country, we age-correct that data to a result of 593 ng/dl in 1985-1986.

Testosterone averaged 537 ng/dl during 1988 to 1991, which is still acceptable. (data from NHANES III)

In 2003 to 2004 testosterone was 541 ng/dl. (Source: NHANES)

For the average American man in the period of 2015 – 2016, testosterone was 459 ng/dl. (Source: NHANES)

Here’s a link to the NHANES studies.

459 ng/dl isn’t far from being officially low testosterone, which is 300 ng/dl according to the American Urological Association. 459 is on the very low end of most studies from before 1980. That means that the average man today has lower testosterone than the great majority of men in the 60’s, 70’s, and early 80’s.

(For info about our sources and methods, including how we used the NHANES data, check here.)

Click here to see our USA article with more details, maps, and charts on the historical changes to testosterone levels in the US.

Animation of the map of USA testosterone levels changing from before 1985 to post 2007

And now a quick word about potato chips!

If you’re here you’re probably interested in avoiding low testosterone. We believe seed oils (the junk food oils found all over the place today) could be one of the modern things that are lowering testosterone.

We have made potato chips with real tallow (beef fat, like the hunter gatherers used to eat) and absolutely no seed oils. Check them out at, or scroll to keep reading this article.

Go here to get tallow fried potato chips
Click the horse to get the potato chips! (Clicking opens )

OK, thank you for your attention and let’s get back to the article!

What About Testosterone Outside the USA?

Testosterone has dropped in much the same way in most parts of the world. But not all of the world.

Here’s how it has changed in the different parts of the world.

Testosterone has stayed at much the same high levels in Uzbekistan and Siberia. In northern Pakistan and in the Caucasus, testosterone levels are also good, and may even have risen.

Sub-Saharan Africa seems to have had lower testosterone in the past (due to disease?), then rose quite high, but now seems to be experiencing testosterone decline too, although it still has good testosterone levels mostly, with the exception of South Africa (this exception is not due to ethnicity, that was checked).

Some of North Africa has acceptable testosterone levels still, as does Denmark, the Netherlands, Belgium, and possibly Britain.

But the rest of Western Europe, Eastern Europe, Latin America, Canada, and the USA have all been experiencing a similar decline in testosterone since the 1980’s.

East Asia seems to have declined around the 80’s and then stayed low-ish, but not awful, since about 1990.

Testosterone trends from 1960 to present in the different regions of the world
Click for full size

In our other article, we show detailed charts of testosterone’s changes from year to year for all the countries.

Here’s a world map of testosterone levels that we’ve animated to show the difference between testosterone before 1985 and the current map of testosterone, so you can watch the change. It only includes the countries where we have data from both eras.

Animation of the world map of testosterone levels changing from pre 1985 to the current day

For a few of the countries, we only had data going back to the 1985 to 1994 era. We wanted to show the testosterone change from the past to the current day in these countries too. So we made an animated map with those countries added. Remember that the other countries are still displaying their pre 1985 data. Here is the animated map.

Another animation the world map of testosterone changing over time

Here’s the middle frame from that animation that shows the map of testosterone pre 1985 in most of the countries, but shows testosterone between 1985 and 1994 in those few countries where we didn’t have earlier data. (Those added countries are Estonia, Greece, Azerbaijan, Egypt, Pakistan, India, Taiwan, Nigeria, and Kenya)

Combined historical testosterone map

(Be sure to check the detailed region and country graphs we have as well, to see all the datapoints and trendlines, since the maps are a bit deceiving sometimes)

Here’s the world map of testosterone levels before 1985. (data from 1962 to 1984)

Here’s testosterone levels from 1985 – 1994.

Here’s testosterone from 1995 – 2004.

Here’s testosterone from 2005 – 2009.

And here’s the current world map of testosterone. The data is as current as possible, so most of it is post 2010. A little bit of the data is from earlier, but none is from earlier than 2000.

Testosterone levels in each country of the world

Raising testosterone back up

We aren’t sure what exactly is causing the low testosterone problem but evidence suggests a large part of it is due to microplastics (source) and “endocrine disruptors” – foreign chemicals that mess up your body’s hormones. Most of these chemicals weren’t around 100 years ago. Major sources of chemicals and plastics getting into your body are shampoos, non-organic food, and synthetic fabric furniture, carpets, and clothes.

Synthetic fabric, like polyester, gives off microplastic dust which you then breathe in. Synthetic fabric in furniture, carpets, and clothes could be the biggest microplastic source in the typical person’s life. “Synthetic textiles are the main source of airborne microplastics”(source). Since microplastics are often xenoestrogens, you may be exposed to testosterone-lowering foreign substances when you are around polyester fabric a lot, whether it’s your pillowcase, clothes, or furniture.

This study discusses the idea that most of the microplastics in your body (perhaps 80%) got in there by inhaling polyester dust in your house from clothes, furniture, carpets, etc.

A cotton sheet, which is a natural fabric that won’t lower testosterone, could be spread over your furniture to help prevent microplastic dust getting into the air and into your lungs. Holy Lamb Organics makes a collection of wool and cotton bedding which you might find helpful.

Here’s their Holy Lamb Organics Wool Comfortor.

In the past, people weren’t exposed to endocrine disruptor chemicals and microplastics. Their clothes were cotton or wool, and xenoestrogens weren’t in their skincare products. That may be part of why testosterone used to be higher.

How high was testosterone 100 years ago or 200 years ago?

Testosterone is measured in the blood. The first time testosterone could be measured accurately in the blood appears to be around 1962. Any claim that “testosterone levels were 5000 ng/dl in the year 1800” is questionable because testosterone could not be directly measured until much more recently. (Unless someone can find some blood stored from back then, and measure the testosterone in it in such a way that the effects of time don’t mess up the measurement.)

However, testicle size correlates with testosterone. Old medical books mention the normal testicle size of their time. So we can use this to estimate what testosterone levels may have been in the 1700’s and 1800’s!

Here’s a chart where we did that.

Testosterone since the 1800s and earlier

As you can see, testosterone appears to be naturally high through the 1700’s, 1800’s, and early 1900’s. Somewhere after 1950 testosterone drops hard. This chart lines up with industrial chemical use very nicely, but there were many changes post World War 2.

Testosterone in the late 1600’s and 1700’s

“Their bigness differs very much in several persons; as big as a Dove’s Egg is reckon’d a mean size”The Anatomy of Humane Bodies, Europe, pre-1682.

Unless dove’s eggs have changed in size, this size would be about 23.29 ml volume, which suggests 847 ng/dl in the late 1600’s.

“Their size is nearly that of a pigeon’s egg” – An Anatomical Exposition of the Structure of the Human Body, Europe, between 1732 to 1772.

Doves and pigeons are in fact the same species, but considering what breed the writer could have meant, and noting the word “nearly,” this size would be about 20.6 ml, which suggests 770 ng/dl in the mid 1700’s.

Testosterone in the 1800’s

“long diameter two inches, its transverse an inch and a half, and its lateral one inch and one-eighth” – Sir Astley Cooper, Britain, first half of the 1800’s.

This would be about 27.29 ml, implying 961 ng/dl in the early 1800’s.

“one inch and three-quarters in length, one inch and a quarter across or in breadth, and one inch in thickness or from side to side”A Practical Treatise on the Diseases of the Testis, and of the Spermatic Cord and Scrotum, Europe or USA, before 1855.

That’s 20.47 ml, which is 767 ng/dl, in the mid 1800’s.

“They are from an inch and a half to two inches long, about an inch and a quarter from the anterior to the posterior border, and nearly an inch from side to side. The weight of each varies from three-quarters of an ounce to an ounce” – Quain’s Anatomy, between 1828 and 1877, quoted in A Text-Book of Human Physiology

This would be 23.88 ml, and 864 ng/dl, in the mid 1800’s.

Ancient Testosterone

In Egypt, there is an ancient cemetery called “Kellis 2” in the Dakhleh Oasis. It is estimated to be from between 50 and 450 AD. They say this was the Roman and early Christian period of Egypt’s history. This cemetery is so dry that natural mummies are found there, and hair has been taken from them for analysis. Testosterone has been measured in this hair. (Link to the study) Hair testosterone correlates somewhat with blood testosterone. The Egyptian males had an average hair testosterone of 21.14 ng/gram. This was compared to a modern sample of men about age 80 with hair testosterone of 13.56 ng/gram, and these modern men, being approximately 80 year old American men in the late 2010’s, would likely have testosterone of about 330 ng/dl by my calculation. By comparing these two results, I calculated that the Egyptians would then have blood testosterone of 514 ng/dl. The Egyptians were apparently an average of 29 years old. Correcting for age, the male Egyptians of this time and place would then have an average testosterone of 439 ng/dl, which is pretty low. However, the hair is from men who died, and so the testosterone in their hair would reflect the time leading up to their death, some of which would likely have been marked by sickness, which generally lowers testosterone.

There is more preserved hair from the past that could be analyzed in this way, but I’m not aware of any other studies that have done this yet.

Testosterone In Hunter-Gatherers

You might be wondering what testosterone levels were like in ancient tribes outside of civilization. We don’t know that, but we do know the testosterone levels of modern hunter-gatherers! These people do indeed have high testosterone usually, but not always. Sometimes they suffer from malnutrition, which lowers hormones. There’s a full article on our site about hunter-gatherer testosterone levels.

Extremely High Testosterone In Outliers

With higher average testosterone levels in the past, there were a few guys at the top end of the range who were walking around with levels that today in most places would probably only be seen in someone unnatural. There are also a few people with insanely high testosterone naturally in some of the parts of the world where testosterone hasn’t fallen. Here are some examples we’ve found.

  • Yakutsk, Russia in 2011 – There apparently were some men who averaged 1510 ng/dl testosterone here. (source) Hard to believe, but the Russian Far East does consistently report high testosterone. Whatever is lowering testosterone around the world has mostly left this area alone.
  • Nomadic tribesmen from northern Kenya, the Turkana people, in 1992.  11 out of 78 men, or 14%, were over 1500 ng/dl. Two were over 2000 ng/dl, and the highest one was 2663 ng/dl. (source) More discussion of that is in our article about hunter gatherer testosterone levels.
  • Pittsburgh, Pennsylvania, in the USA in 1980. Out of just 11 “healthy volunteers” the highest was 1501 ng/dl, the 2nd highest was 1297 ng/dl, and the 3rd was 1055 ng/dl.  (source)
  • In Nijmegen, The Netherlands, during 1974-1975 – Out of 15 men, the highest was 1293 ng/dl, the 2nd highest was 1144 ng/dl, and the 3rd was 1029 ng/dl. (At various times through the year) (source)
  • Probably In 1978, in Moscow, Russia, the “maximum” level out of 81 young men was 1499 ng/dl. (source)
  • In 2011-2012 in Amirkola, Iran, a mountain village, older men with an average age of 70 were studied. Out of 830 men, the highest result was 3475 ng/dl. Two more were also over 3000. The top 3% of the men (27 men) were over 1475 ng/dl. (source)
  • In 2006, among Hmong people and other rural northern Thai people – out of 65 men from Pong Yaeng (mostly Hmong), the highest level was 3010 ng/dl. Out of 68 men from Inthakhin, the highest level was 2400 ng/dl. Both these would probably flag a steroid test in the US, but I doubt these rural farmers were anything but natural. (source) The average testosterone among the mostly Hmong farmers in Pong Yaeng was 975 ng/dl at an average age of 37. Unfortunately I can’t find the individual results from all these farmers, although I thought I had seen this at some point.
  • Villages (“Jago and Badeku,” along the river Oshun in the jungle of SW Nigeria) outside Ibadan, Nigeria in 1987 –  In those with untreated parasites, testosterone was 987 ng/dl, but in those with treated parasites, testosterone was 1200 ng/dl. (source)
  • Peshawar, Pakistan recently – 1090 ng/dl average in 18-25 year olds (source) in 2016, and another study finding an average of 908 ng/dl in 18-25 year olds in Peshawar in 2019. The highest of these 115 men was 1690 ng/dl. And 13% of them had testosterone over 1200 ng/dl. (source)
  • Around 1966 in the USA, quite likely in New York City, among men aged 20-45, the highest number among 60 men was 1440 ng/dl, and the second highest was about 1180 ng/dl. (source)
  • Explorers from India on an Antarctic expedition had their testosterone go from 910 in 1985 in New Delhi, India up to 1294 ng/dl in Antarctica in 1986 on the  “Sixth Indian Antarctic Expedition … at Dakshin Gangotri” (source)
  • Montana, USA in wild firefighters in 2020 – they averaged 1200 ng/dl testosterone apparently. (source)
  • Nebraska, USA in 1981 – out of six guys, one of them had 1230 – 1505 ng/dl testosterone, and another had 1036 – 1170 ng/dl testosterone, depending on the method used to measure it. (source) I’m pretty sure this was not a random sample though, I think they may have selected unusual testosterone levels on purpose.
  • In 1996 in Ann Arbor, Michigan, USA, four healthy men, averaging 27.5 years old had 1151 ng/dl testosterone. (source)
  • In Belmont, Massachusets, USA in 1974 among some early 20’s men, average testosterone was 1115 ng/dl (source) (These men were heavy marijuana users and, although evidence is not clear on this subject, some evidence points to long term marijuana use lowering testosterone.)
  • Out of seven healthy young men, age 24-29, in England or Scotland in 1974, one of them hit 1120 ng/dl testosterone. (source)
  • Chita, Russia in 2012 – At age 34 they averaged 1022 ng/dl. (source)
  • In the “Jordan Valley” of Jordan between 1997 to 1998, the researcher writes that testosterone fluctuates from 480 in February to 1660 ng/dl in June. (source) While other studies do find a mild seasonal fluctuation in testosterone, this is by far the most extreme fluctuation. So I do wonder if there was an error in the study maybe. Also, a different study on Jordan did not find such high testosterone at all.
  • Ahwaz, Iran in 2016 at age 20, “10 male physical education students of
    Shahid Chamran University of Ahwaz
    ” averaged 1100 ng/dl. (source) However, since these were phys ed students and since all the other data I have from Ahwaz actually shows low testosterone, I suspect there may have been steroid users in this sample.
  • This paper from 2014 found Russian athletes to have about 2200 ng/dl testosterone, but this is highly suspicious in light of potential steroid use. (source)
  • In Florida in 2015, a study on young, experienced lifters found 1075 ng/ dl on average. (source) However, this is suspicious due to potential steroids affecting the sample.
  • In Florida in 2016, a study on mostly state championship powerlifters found 1309 ng/dl testosterone, but again this is suspicious because of the potential use of steroids. (source)
  • Vietnam, 2018 – Olympic cyclists have 1070 ng/dl test at age 19. (source) Again, that’s questionable because of potential steroid use.


Testosterone has fallen drastically in most of the world from healthy levels to unhealthy ones. The big fall has occurred from the early 80’s onward. It might be that this is part of a larger trend of testosterone falling from very high levels before the middle of the 20th Century, but much more evidence would be needed to say that. The fall of testosterone from 1980 to today has lots of evidence though. Nobody seems to know what is causing this. While obesity correlates strongly with low testosterone, an NHANES study (link here) showed that even men with a healthy weight are much lower testosterone than they used to be.

I can think of a few ideas about what is causing this:

  1. PUFA consumption has risen through the twentieth century and especially after WW2 – some think this may be driving the obesity and chronic disease increase. I think it might be involved in low testosterone as well. More info here: PUFA Might Lower Testosterone
  2. Chemicals and Plastics. The use of agricultural chemicals really took off in the decades after WW2. Read more here: Pesticides May Lower Testosterone Synthetic plastic was invented in 1907, and plastics have been increasing ever since. Plastics accumulate in the environment and in our bodies, and they are known to disrupt testosterone. There is a whole host of other chemicals that we are now exposed to as well, such as flame retardants in the furniture and preservatives in the food.
  3. Radio waves. One study found that mice exposed to a long cell phone call every day had much lower testosterone. Our world is awash in radio waves. Over the 20th Century this has grown from almost nothing to very high exposure in the 21st Century from the cell phone in your pocket mostly! I plan to write more about this.
  4. Social Changes. There have been many social changes that have occurred in this time. Possibly people feel less purposeful, less independent and more helpless, defeated, and disoriented in the face of high technology, the loss of “traditional values,” mass society, mass media, powerfully armed states, very large corporations, high amounts of regulation, and cultures that value intense education and “professional” work for a large company. Internalizing certain attitudes likely affects hormones. One study has found that Americans in 2007 were quite a bit more likely to be mentally disordered than in 1938. (Source)