Dear Mark: Why are Male Fertility and Testosterone Levels so Low?

3d rendering group of white spermsFor today’s edition of Dear Mark, I’m answering just one question. But it’s a good (well, maybe not good, but certainly important) one: Why is male fertility on the rise and testosterone on the wane? The popular notion is that women flushing birth control pills and peeing estrogen-rich urine into the public water supply are the primary reasons for the sex hormone issues facing men, but I’m not so sure. Let’s explore what else might be causing the problem.

In the comments from last week, tribal wrote:

I also heard about a report that indicated that our water supply is also contains more and more estrogen, primarily due to the increased use of birth control tablets, which find their way into the water supply – I need to research the truth to this report. testosterone levels have halved for men in the last 20 years, and at this rate will will end up self-destructing.

The main thrust of your assertion is true.

The water supply is full of estrogenic compounds.

Male sex hormones have plummeted in the last half century and show little sign of rebounding.

However, birth control pill use isn’t the biggest culprit. In a 2011 review of the evidence, researchers found that the contribution of synthetic birth control estrogens to the total estrogen content of public water was negligible. Women flushing pills or excreting urinary estrogen do not appear to be the main cause of estrogen in the water supply.

Estrogen in the water may not even be the main cause of the growing male fertility problem. And if it were, what exactly could you do beside drink more bottled mineral water (and even that’s not a guarantee)? Spend thousands on expensive filters, stress out every time you had to satisfy a basic biological requirement (drink water)? It makes more sense to worry about the things you can control, like what you eat or how you live. As it turns out, the biggest culprits for impaired male fertility are probably dietary and lifestyle-related.

Omega-6/3 intake: The polyunsaturated fats we eat are incorporated into the structure of our cells—all the cells. Omega-6-rich cellular membranes are less stable than membranes with more MUFA, SFA, and omega-3 fats, and that goes for cellular membranes of sperm cells. Studies show that men with higher omega-6:omega-3 ratios have lower sperm counts, less sperm motility, and more infertility.

Oxidized fat intake: Most of the polyunsaturated fat most people eat has been refined, oxidized, and exposed to tons of heat, light, and oxygen. Omega-6 fatty acids are already liable to oxidize and turn rancid. They way we treat them before eating—as frying mediums for days on end, in high-heat stir fries, in packaged junk food subjected to high heat and left on the shelf for months—guarantees they’re almost completely damaged. The higher the MDA (a metabolite of oxidized PUFA) in the sperm, the greater the chance of male infertility.

Low sun intake: Most people fear the sun, focusing only on the skin cancer risk and ignoring the myriad benefits of sun exposure, one of which is the fact that it helps us synthesize vitamin D. Vitamin D is a pro-hormone, meaning we use it to produce a variety of hormones. One of the most important products of vitamin D is testosterone, the male sex hormone. Without adequate testosterone, reproduction becomes difficult. We produce less sperm, lose our libido, and become less attractive to potential mates.

Low red meat intake: The campaign against red meat has worked. Most people still think red meat is inherently dangerous. Red meat consumption is at an all-time low, and chicken consumption is at an all-time high. This development has probably caused major problems for male fertility. Red meat is the best and most reliable source of zinc, an important nutrient for male fertility. Red meat is the best source of carnitine, an amino acid with pro-fertility effects. Red meat is higher in fertility-protective saturated fat and monounsaturated fat and lower in unstable omega-6; chicken is lower in SFA and far higher in omega-6.

Those are the big whoppers, as I see it, the factors regular people suffering from low testosterone/fertility can actually target with the most ROI. Sure, it’s not going to happen overnight. Those seed oils are everywhere. Everyone loves French fries, and no one wants to know how long those fryers have been heating the same oil. Red meat remains scary, as does the sun. But it’s physically possible for a regular person to make four simple changes—eat less omega-6, have some canned sardines twice a week, choose steak over chicken, and go outside every day—that could have huge positive ramifications.

There are other major causes, too, including perhaps the estrogen in the water issue as well as other estrogen-like (xenoestrogen) pollutants. If you guys are interested, I can explore this topic more down the line.

Thanks for reading, everyone. I’d love to know your take on the issue. Let’s hear it!

Primal Kitchen Ketchup

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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41 thoughts on “Dear Mark: Why are Male Fertility and Testosterone Levels so Low?”

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  1. Yep, and it works. Do all the above (red meat, sardines, sun and supplement vitamin D) plus I lift heavy things in the gym. At 57, in the best shape of my life. Muscular still and Mr. Happy down below is always bugging me.

  2. Perhaps this is Mother Nature stepping in to curb population growth? It happens in other species, so why not ours? In fast-reproducing species with large litter size, females may cease to ovulate. In ours, where female reproduction rate is relatively slow and litter size small, it seems logical that natural forces might work more strongly in males, whose ability to procreate is limited only by access to fertile females.

    1. Our developed world population is declining, Suzanne. Population growth is a byproduct of industrial or technological evolution, after which the demographics start to settle down and actually slow down procreation rate once advanced education kicks in.

      Population growth is a big issue in developing nations, which are yet to or are already going through their own versions of modernization. The anthropomorphized Mother Nature sure isn’t trying to curb that down. Our genes don’t have a self-limiter coded in to prevent us from population explosion.

      And it sure doesn’t happen in other species that have flooded the ecosystem following abrupt climatic or ecological changes either. Think jellyfish in the oceans, rabbits in Australia, algal blooms leading to coral reef endanger, or any ecosystem dysbiosis caused by human intervention.

      It wasn’t the animals’ genes that prevented the overpopulation, it was nature balancing itself out.

      We, however, have become smart enough to override nature’s response, to our own detriment. We can make long-lasting impact on our planet and evolution will not be able to catch up. I think the best bet when it comes to low testosterone levels and male infertility is that it isn’t the natural genetic reaction, but that it’s a man-caused disruption as well.

      Our sperm count and quality halved in the last 40 years, in developing nations, and that sure isn’t nature speaking. That’s pollutants, inadequate gene expression, inflammatory dieting, and mind-body disconnect at work. And the numbers prove us right. In nations where overpopulation is at play (developing nations), the farther away you are from modernization and the industrialism process, the more fertile you are.

      Sometimes, perhaps, too fertile.

  3. Body fat produces estrogen so extra body fat could account for much of the issue. Also soy consumption.
    Also, typo alert…I think you meant to say rising infertility in the third sentence.

  4. Uh…plastics? Phthalates? Bisphenol A? Pesticides? Herbicides?


  5. Really interesting post. And so many women are having problems with fertility too. I know I saw a study years ago that showed women consuming fat free/low fat dairy were more likely to be infertile than those consuming full fat dairy. I don’t think there is just one cause of these changes, but the changes in the fats that most people are consuming has to be affecting hormones in a negative way. People are regularly consuming fats that their bodies don’t even recognize as real food. So wouldn’t be surprised if that has quite a bit to do with infertility in both sexes. I know I feel way more balanced now that saturated fat (and more fat in general) is a part of my life:)

  6. Missing from this conversation, everywhere, has been the behavioral aspect.

    Primal male responsibilities are protecting and providing for their families and the tribe.

    Instead we see men being cowards and men indulging themselves. We see it so frequently, we may be excused to consider it normal.

    Is this behavioral aspect the effect or the cause of low male fertility and testosterone?

    It is a vicious cycle, a chicken-and-egg dynamic. We must try to break it at both ends. Both with nutrition and behavioral choices.

    To choose to be better protectors, men might consider:

    * Taking challenging, but manageable risks
    * Risking, dealing with, and working around injuries
    * Getting stuck in difficult or dangerous situations and improvising a way out

    To choose to be better providers, men might consider:

    * Thinking of others as much as possible, rather than themselves
    * Asking questions rather than giving advice
    * Bringing something home from their adventures, even something symbolic like a flower, for those who couldn’t come

    These things worked for me. My first child (before these habits) took several years to conceive. My last two children (after these habits) were conceived on the very first attempts.

    Of course there is a nutritional aspect as well. One might include foods that were traditionally consumed by alpha hunters (raw liver, stomach contents/fermented veg, other organ meats). It is quite possible these foods have an epigenetic effect beyond their gross nutritional content.

    Male infertility is a very important threat which must be surrounded to be destroyed. Preferably with a sledgehammer.

    1. “Civilization comes at a cost of manliness. It comes at a cost of wildness, of risk, of strife. It comes at a cost of strength, of courage, of mastery. It comes at a cost of honor. Increased civilization exacts a toll of virility, forcing manliness into further redoubts of vicariousness and abstraction” ? Jack Donovan

      The way of men is endangered. As you’ve pointed out Timothy… it doesn’t have to be that way! One of the best, most influential books that wife and I have had the pleasure of reading is Jack Donovan’s book The Way Of Men. I hope at least one person here sees this and gets the book.

      Love what you said about raw liver and the sledgehammer.

      1. Thank you for that book recommendation! I value your comments so I picked it up.

        The most compelling reads I’ve found on the subject have been war memoirs from the first half of the 20th century, a period that seems to have catalyzed the decline of masculinity, and not just from the toll in lives. Fussell, Jünger, Barbusse, Plowman, and Solzhenitsyn all paint vivid pictures of masculinity in decline across each of their cultures.

      2. I can’t tell you how much I love this perspective. The body conforms to expectations and needs. One doesn’t need as much testosterone to lead a civilized life.

    2. +1 Behavior seems to be a crucial component. I have never felt more confident than the previous 4 months of regular lifting. Also doing (Primal) things the vast majority of society eschews provides that risk taking Timothy talks about. Sun exposure, walking barefoot, eating weird things, getting into nature, taking cold showers, etc. etc. I have to think my T is soaring these days, although, unlike Timothy, I won’t test it by conception attempts. Just practice with the wife for this guy. 😛

    3. That’s why I wield my 20 pound sledgehammer every week in the beach, fiercely hitting the sand. If I am lazy I take the 16 pound.

    4. If we are talking behavioural aspects, I have one more big whopper to throw in. Falls in testosterone levels have correlated with the rise in feminism. As women have yearned to become like men, have men now instinctively given up on the job ?

      We constantly see in the media, workplaces, and western society in general that “women don’t need men”, well ladies, you may just get your wish.

      I guess Newton’s third law of motion is a real bummer…

      1. That is a great chicken-and-egg question. However it gets started, the cycle of women demanding fewer men, resulting in a shrinking supply of men, resulting in women adapting to demand even less of men, until the traditions that nurture masculinity are forgotten, does not historically yield a happy conclusion.

        Both sexes lose from the failure of that fundamental division of labor on which human social organization has always relied.

        One interesting example is ancient Sparta. During that culture’s ascendency, Spartan women were unique in Greece for being able to control their men: “because we are the only women who give birth to men,” quipped Queen Gorgo.

        Years of heavy warfare, however, took its toll on the most masculine members, and Sparta quickly devolved into a gynocracy whose women “were intemperate and loved luxury” (Aristotle).

        Comparisons with modern Europe are all too apparent, but stranger that America should be so affected, where masculinity seems to have been stripped away by a simple overabundance of wealth.

        Yet there is always a remnant to begin the cycle again…

  7. Sugar consumption increasing was my first thought. Sugar hurts every aspect of our bodies.

  8. The Art of Manliness had a good article years ago on increasing testosterone. I believe this is all a matter of diet, lifestyle, and culture. SAD is basically a testosterone killer and the current social climate isn’t much better. Stress too. Cortisol is like anti-testosterone.

    It’s unlikely it’s one thing. All evidence points to a broad spectrum of issues, most of which can be solved with hitting the weights, eating muscle foods, removing junk, and… “growing a pair” so to speak.

    Just tack this up as another case of “better living through chemistry” and “better living through industrialization.” You know how we like to make fun of “barbarians” from the Dark Ages? Yeah, I imagine the people 200 years from now are going to feel similarly about us.

  9. A few extra hours of sleep can double your testosterone!! Source — pubmed/17520786

    Adding in magnesium oil increases your testosterone!! Source — pubmed/20352370

    Avoiding non-native clothing can increase your testosterone!! Source — pubmed/8279095

    Avoiding non-native EMFs and wifi can increase your testosterone!! Source —

    As I’m reading the article I’m furiously complaining to wife about all the things you missed… all the “little” things that really don’t matter if you don’t make these four simple changes that you suggest. Thank you for another great article with “practical” things our population can implement in hopes of saving our species.

    1. Yeah the WiFi thing is scary – its all around us now, even office’s are ditching copper network cables for “WiFi”, which means propagating WiFi routers all over the place, as if its some sort of benefit or breakthrough, which is ridiculous if you are sitting at a static workstation that will never need to be moved – why have a WiFi router siting above your head all day ? – its even built into our cars now, so when you get in a car you are in a steel shell with WiFi being emitted inside the car, not to mention your mobile will go into boost mode to get a reception through the steel “Faraday cage” of your car.

      At home I minimise all my WiFi, everything is connected with physical copper LAN cables where possible – its scary how people dismiss the potential dangers of being surrounded by WiFi routers everywhere, like a streak in a microwave oven.

      Microwaves ovens and wifi generally can operate in the same radio frequency range (about 2.5 GHz), the only difference is the power output from the WiFi is much lower than a microwave oven, the point is though, that its in similar frequencies, meaning it will easily be absorbed by things that conduct, i.e., iron, copper, steel – your flesh.

      For example. Low frequency radio waves just pass you by and don’t interact with your molecules, but WiFi does, and that’s a straight out scientific fact, regardless of “how low the wattage”.

  10. It doesn’t necessarily cost “thousands of dollars” to RO filter your water. I’ve been using a faucet mounted RO unit from an RV supplier that works very well, proven by a TDS water tester that shows ~150 ppm going in, ~10-14 going out. Another Primal product opportunity?

  11. Possibly the result of a species-wide mutational meltdown? In his book ‘The Genius Famine’, author Bruce Charlton suggests that average intelligence levels and the prevalence of so-called geniuses has been on the decline since the Industrial Revolution due to the accumulation of deleterious gene mutations. Could the decline of male fertility and testosterone levels have a similar cause?

  12. If you haven’t yet, look into how Zinc plays an important part in increasing testosterone levels, especially in conjunction with Magnesium. I saw a huge improvement in testosterone blood test levels after including these. Highly recommended to take Zinc and Magnesium a couple hours before you go to bed.

    Here’s a study on it:

    1. Not sure if I missed something or not, but the study you cited shows that Zinc and Magnesium does NOT significantly alter testosterone.

  13. Since I eat red meat regularly, have sardines or salmon a couple times a week, engage in heavy lifting, and work outside several hours per day, my fertility must be pretty good. But I don’t really have a reason to test it, since I’ve already sired all the children I care to make.

  14. Epigenetic failure? Between steadily reduced nutrient uptake, increased administrative dominance, and 1000+ years of certain religions killing the strong, independant, and intelligent while rewarding conformity and obedience, it’s to be expected.

  15. Hi Mark, I’ve been follow the primal blueprint for ~5 years, including the four testosterone enhancing recommendations above, but my testosterone has continued to slide. Admittedly, I’m almost 70 and it’s supposed to slide, so what’s your take on injecting cypionate as a hormone supplement? I love its effects and want to continue, BUT IS IT PRIMAL?

  16. Not sure about the case for red meat in this context. The male infertility “epidemic” is more or less restricted to Europe and North America, where people still consume more meat – including red meat – than those living in the rest of the world. Meanwhile, most of the Third World is actually super-fertile; even though the vast majority of people living there subsist on very limited diets with a low overall meat consumption. I’m suspecting that xenoestrogens, the omnipresence of plastics, tight clothes made of synthetic fabric, hot tubs and showers, heated car seats, sedentary lifestyles with low overall physical activity levels, and yes, too little sun exposure and way too little time spent outdoors are the main culprits.

    1. Most Europeans and North Americans do not eat grass-fed red meats that have tons of nutrients and omega 3 fatty acids. The infamous study that correlates red meat to cancer, too, fails to make this distinction.

      While red meat from healthy game can be a therapeutic “superfood”… eat meat from a grain-fed obese animal, process that very same meat by intense heat, intense oxidation, frying it, sprinkling it in n-6 PUFAs and cooking it for hours, then adding preservatives for shelf-life, forming nitrates, sitting on the shell for half a year… And yummy, directly into the customer’s belly (or worse, recooked), along with who knows what sugar-filled & more inflammatory fat-filled sauces that are meant to enhance taste.

      You may as well eat a spoon of cancer. This is exactly what Mark is talking about in the article. Not all types of red meat are the same. Asia and Africa eat a lot of fish which is abundant in coastal and lake regions, and also sometimes beef, goat, chicken, or sheep… Which are a good source of Omega 3 (especially the fish). Well, at least they aren’t CAFO.

  17. Hey Mark, nice article. I’d like for you to explore the topic more if you have the time.

  18. Have you considered the research linking disposable diaper use and male infertility? Along with other factors, it’s worth considering.

  19. It would be interesting to have a graph showing sperm count VS BMI.

  20. I also see a ton of “healthy” wives giving their spouses the same thing they eat such as loads of flax which may be good for female hormones but lowers testosterone!

  21. the typo mentioned still stands — did you mean to write: “Why is male infertility on the rise and testosterone on the wane?” rather than “Why is male fertility on the rise and testosterone on the wane?”

  22. Scientific American ran an article several years ago about many pesticides being shown to either block testosterone or mimic it. Omega 6s may be a problem themselves, but they often come from grains, which are often heavily sprayed and so may be more prone to having chemicals in or on them that affect testosterone. Could be a combination?

  23. I didn’t see anyone else mention it, so I thought I should – pseudoestrogens in sunscreen are also a source of estrogenic compounds in our water supply… so much so that they are adversely affecting fish and marine species’ reproduction in the open ocean and the health of reefs. Ditch the chemical soup sunscreens, embrace natural clothing as a cover up, or use a mineral-based sunscreen; the benefits will extend beyond ourselves.

  24. Mark – thanks for addressing this topic, I almost missed it, I was a bit behind on my MDA articles – didn’t realise my comment had been used as a basis for an article, so much appreciated.

  25. Sperm do not like heat!! Try to find a male mammal that DOES NOT have external testes!! Twenty +years ago there were articles about wearing boxer shorts to decrease heat exposure to testicles. Now most men wear tight under shorts and tight outer pants. One should check Pubmed for previous articles.