Vegan Men: More Testosterone But Less Cancer

NF-Feb12 Less Cancer in Vegan Men

Just a few days of walking and eating healthy plant foods can lower the level of the cancer-promoting growth hormone IGF-1 enough to reverse cancer cell growth in a Petri dish. This is detailed in my last three blog posts Cancer-Proofing Your BodyTreating an Enlarged Prostate With Diet, and How do Plant-Based Diets Fight Cancer?

We know decreasing animal product consumption decreases our IGF-1 levels, but how low do we have to go? How plant-based does our diet need to get? In my 2-min. video How Plant-Based to Lower IGF-1? the IGF-1 levels are compared between men and women eating conventional, vegetarian, and vegan diets.

Vegan men tended to have significantly higher testosterone levels than both vegetarians and meateaters (see graph here), which can be a risk factor for prostate cancer, the reason plant-based diets appear to reverse the progression of prostate cancer may be due to how low their IGF-1 drops (see Cancer Reversal Through Diet?).

Boosting cancer defenses within just days of eating healthy is a remarkable finding. For those interested in the whole story, I started out introducing Nathan Pritikin and the elegant series of experiments that became part of his legacy.

Researchers were able to demonstrate the mechanism by which a plant-based diet and exercise could suppress the growth of breast and prostate cancer cells and protect against prostate enlargement (more on prostate problems in Some Prostates are Larger Than Others and Prostate Versus Plants).

I also asked and answered Is It the Diet, the Exercise, or Both?

Finally, for those interested in whether lower levels of growth hormones in vegans might interfere with the accumulation of muscle mass, see my 3-min. video Plant-Based Bodybuilding.

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.

Image credit: edwick / Flickr

  • Thank you so much for posting this, I’ve been wanting to share my personal experience and do a blog post about this forever!

  • Ray Mitchell

    Nearly all of your posts and videos relate to the impact of whole plant foods on the physical body. Are you finding anything on the impact of diet on mental health, intelligence, personality and mental disease? This subject are really interests me. The closest thing I am aware of is your material on Alzhiemer’s. What about bipolar disorder? Schizophrenia? What about sleep, dreaming? Apnea is related to weight and hence is impacted by diet. What are you seeing in the literature?

  • Avi

    “Vegan men tended to have significantly higher testosterone levels than both vegetarians and meateaters (see graph here), which can be a risk factor for prostate cancer,”

    I am confused doctor, it basically says that Vegans men are more likely to get prostate cancer?

    • Joao Burini

      No. Lower IGF-1 counters that.


        That’s poorly articulated in the article.

      • Frasier Linde

        The article says, “the reason plant-based diets appear to reverse the progression of prostate cancer may be due to how low their IGF-1 drops.” Notice first the “may,” then the fact that the linked video claiming “cancer reversal through diet” cites studies that all use comprehensive lifestyle interventions, not diet alone. Nothing here speaks directly to prostate cancer risk among vegans per se, nor definitively to IGF-1’s role in it.

        • JC
          • Frasier Linde

            The problem there—as is often the case in reporting on this topic—is that the author sees benefits from removal of poor-quality animal foods (including dairy and eggs, which are common inflammatory triggers/allergens), and then (fallaciously) concludes that all animal foods are bad. This kind of thinking puts one at risk of “throwing the baby out with the bathwater.”

          • Enric Martinez

            Why exactly?

          • Frasier Linde

            I’m not sure what you’re asking about.

          • Enric Martinez

            Why exactly is this kind of thinking putting one at risk of “throwing the baby out with the bathwater” ?

          • Frasier Linde

            Because there is plenty of nourishment to be gained from high-quality animal foods if you don’t think they cause prostate cancer and other health problems. Giving up ALL animal foods because SOME of them MIGHT be bad for you fits the above idiom exactly.

          • Enric Martinez

            This answer makes no sense:

            So, if I did believe that they cause prostate cancer as a result high quality animal foods stop hing plenty of nourishment? How exactly?

            And what type of “animal food” ? Animals eat all type of food?

          • Frasier Linde

            You stop gaining nourishment from animal foods if you stop eating them due to fear of prostate cancer or other problems. I could have said “animal source foods” to be clearer, but I suspect you know what I mean and are just being contrary.

          • wannabemdd

            So… that’s why animal eaters LIVE LONGER and have LESS CANCER than plant eaters?

            I could go on about how one stops gaining “nourishment from sitting on ones behind” from not exercising or how eating a cup of blue berries everyday causes depression due to remembering the “good old days” with your friends who bit the dust/ lost their mind due to diet. I honestly believe that the meat is causing premature decline in cognitive performance as shown in your post.

  • rick

    reccomendations for diet for chd and chronic heart disease?

  • Colin P. Müller

    Vegan men are also whiny liberal P U S S IES. I rather eat steak and be a real man.

  • Jo

    I am a 33-year-old male, recently turned vegan (from vegetarianism). I suffer from low testosterone levels, and I have not seen them improve as a result of transitioning to veganism. (Stress and a one-time testosterone injection may have been a factor at some point in suppressing my own production of the hormone, but I am currently happy, low-stress and vegan and still have below norm levels.) Before I decide to take hormones for the rest of my life – I might not have a choice – I was wondering what vegan foods in particular could help me to boost my testosterone, so that I could try them over the next few months. I have also been avoiding soy recently due to the possibility that plant-based estrogens come into play.
    I am quite struck that your website says that on average vegan men are doing better with testosterone.

    • Thea

      Jo: Sorry to hear about your hormone troubles.

      I don’t know the answer to your specific question, but thought I would point out that Dr. Greger does have a video or an article about how licorice can lower testosterone levels. So, that would be one food/tea to definitely stay away from.

      Good luck.

    • Toxins

      What constitutes your vegan diet? Are you avoiding processed foods? Do you eat plenty of greens, whole grains, and fruits?

      • jo

        Thanks for your prompt responses. I didn’t realize that they came so fast.
        I do eat plenty of fruit and vegetables, nuts, and whole grains. Should I be consuming more fat? Anything in particular? Any key nutrient that I might be missing?

        • jo

          I do not consume much processed food.

        • Toxins

          I am not an expert in the area of raising testosterone. You can try including ground flaxseed in your diet to see if it helps. If your diet is made of whole unrefined plant foods then I am unsure what specifically there is I can recommend. Perhap others may respond to this issue.

          • jo

            Thanks for letting me know.
            By the way, if there is any clarification needed, I am not sharing my story in order to discourage anyone from becoming vegan or anything. The internet is full of stuff about veganism not being good for one’s testosterone levels, but I have no idea if that’s credible at all. It might well be the case that I have a diagnosable condition that’s unrelated to my diet.
            If anyone else on your team can chime in with more ideas, that would be greatly appreciated.
            Thanks for your ideas!

          • Eisenhorn

            google PES Erase + DAA for test. Legal and safe just check it out, I’m not selling you anything here.

          • Vaalea D

            Hi Jo, this page might be helpful.


            She says “Cholesterol is a type of fat found only in animal foods. Vegans do not intake ANY dietary cholesterol. Human bodies do produce cholesterol, however, that’s only if the body is healthy. Cholesterol is produced in the liver. My liver had been abused by many years of drinking, smoking, caffeine, and then eventually, pregnancy.

            Cholesterol is the precursor to all sex hormones (like estrogen, progesterone, etc). Without adequate cholesterol, the body cannot make hormones.”

            Then she goes on to describe the dietary changes she made to improve her health “Eating as much saturated fat (coconut products, cacao butter) as possible because saturated fat stimulates cholesterol production. Also, eating plenty of other healthy fats, like olive oil, nuts, and avocados.” but adds ” I would be remiss if I didn’t mention that although I believe a low-fat vegan diet is excellent for reversing and curing many chronic diseases, that does NOT mean that it’s the right diet for everyone. A diet for healing is different than a diet for maintenance,”

    • Daniel

      you must consume cholesterol, hormones are made of of that

      • wannabemdd

        you must die, life is made from that.

    • Gloria Schroeder

      One study I read, mentioned vinegar is one step from being testosterone. I would drink it diluted, with and after meals daily. Remember, B 12 comes from animal products (eggs milk cheese), and without you have no stomach acid, which will negatively affect all systems, even causing bone spurs, and soft tissue calcium deposits. Without stomach acid, you will not produce enough niacin, which is needed to produce sex hormones. I suggest this supplement in doses of 50 mg. with each meal. Also, fermented, and sprouted soy presents a lowering of toxins, not an increase. Vegetarians have 50% less cancer causing toxins in their plasma. So, I suggest eating plant based diet, including fermented soy, and eggs milk and cheese and lots of pickles and vinegar products. Good health to you.

      • Cinzex

        No not even the point that only animal products have b12 is completely true. There are microorganisms on the ground which animals eat so these microorganisms live in the gut from the animals. But the microorganisms are also present on vegetables from the ground etc which are covered with dirt but by washing and cleaning away all that dirt there is no b12 left nor isnt much b12 left in the animal products because there are not adequate portions of b12 in the meat. So just take a b12 supplement that is the best choice you can do. Even meat eaters have low b12 levels

      • Cindy

        Soy can be quite dangerous really. It DOES raise estrogen levels and high estrogen levels have been linked to blood clots, pulmonary embolism, and stroke. Speaking from personal experience, I began eating soy based protein bars as quick meals while I was working. After doing this for several months I developed a blood clot in my right calf and a month later I developed 2 more in my thigh.
        My father in law went on a vegan diet that included soy and a few months later he developed a clot that went to his lungs and almost killed him.

        • Enric Martinez

          Indeed, Soy is quite dangerous raising the estrogen levels in RATS.
          It does however not seem to affect Asians at all, and there are at least 4 billions of them.

    • Enric Martinez

      Try supplementing magnesium and zinc, this together with exercise should do a good job.

    • Jo, try Biogenesis. When men take BioGenesis, they see a jump of about 5% in testosterone levels. BioGenesis has resveratrol which reduces aromatase- Aromatase is a female hormone that both men and women have. In women, Aromatase causes breast cancer, in men, Aromatase covers up testosterone. Check it out at

    • Amo

      Jo, maybe it’s a little late to respond to you but i have encounter the same probleme as you.
      The increase of fat (saturated, monosaturated) help a lot et give me the joyce of life again… I’ve restart a vegetarian diet (because of all the same claim i suppose you have found) and now try to do the same as 100% vegan, so coconut oil, avocado etc…

      You must check your zinc, D, and selenium too…

  • Alexander Mark

    You say that vegan men have HIGHER testosterone… yet nowhere do you cite this. You link to an irrelevant graph (one also produced by you). Where is the research that shows vegan men have higher testosterone?

  • sceptic

    Why does the photo only show mannequins? Is it that hard to find a muscular vegan male?

    • JacquieRN

      Just switching it up! Not hard at all…

      This guy is crazy huge:

      How about a google image search – not bad!

      • Thea

        JacquieRN: Nice!

        Here’s some more serious vegan muscle:
        This guy recently broke a world record in weight lifting. “Congratulations to Strongman Patrik Baboumian who yesterday took a ten metre walk carrying more than half a tonne on his shoulders, more than anyone has ever done before. After smashing the world record the Strongman let out a roar of ‘Vegan Power’…” For more info:

        Other vegan muscle of interest:

        (article from meatout mondays)
        Vegan Bodybuilders Dominate Texas Competition

        The Plant Built ( team rolled into this year’s drug-free, steroid-free Naturally Fit Super Show competition in Austin, TX, and walked away with more trophies than even they could carry.

        The Plant Built team of 15 vegan bodybuilders competed in seven divisions, taking first place in all but two. They also took several 2nd and 3rd place wins.

        For More Info:

        • Thea

          OOps. I see you already linked to the weight lifter guy. Oh well, it’s fun to see him twice.

          • Patrik did not build that body with a vegan diet. Getting jacked eating an omnivorous, meaty diet and then switching to veganism is not the same as building up from scratch. Bill Pearl who is also always brought up, falls into this category, though he was lacto-ovo, I believe.At least Patrik is big, badass, and strong though. Some of the guys you vegs like to cite are skinny (by musclehead/bodybuilding standards) and unimpressive. Absolutely not taking away from these guys, but the only problem I have with vegans is the widespread disingenuousness, and sometimes outright falsehoods.

          • RunsWithPoodles

            The meat and dairy industry must make you crazy!

          • Dan

            These are not falsehoods at all…. High testosterone does not necessarily mean “big” or “beefy” or anything like that. It usually — note: usually — means more muscular (which does not necessarily mean bigger muscles), less fat around the breasts, less body percent fat, high energy, etc.

    • Dan

      A former Mr. Universe is now vegan — granted, he was not vegan when he was Mr. Universe, HOWEVER, he still IS muscular, even in his 70s! Google “openly gay black vegan former mr universe” or something like that.

      • Dan

        Found him: JIM MORRIS. This guy is AMAZING! In his 70s, he is more ripped than most jocks I know! And he has been vegan for quite some time.

  • Alexis

    Hi. I’m a 28 year old female vegan bodybuilder. How much protein do I need if I were to weight train six days a week for a hour.

  • Dan

    Jo, and anyone else who wants to raise testosterone:

    -1) I’m also in your shoes. As a male, I want to reduce my breast size. I have slightly done that, gradually, by fasting over 12 consecutive hours a day AND drinking a TON of water.
    -2) I understand that these two lifestyle changes are easier said than done, and also, they take TIME — expect it to take at least 3- weeks before seeing any definite results.
    -3) Another idea is to go on walks outside for just 25 minutes a day. 12 and a half minutes one day, and the same on the way back. You can even pace around your own apartment/house/dwelling 25 minutes a day.
    -4) Finally, as noted, please stay away from processed foods — the fewer the ingredients, the better!

  • Ron

    I have a couple of questions on the role of cholesterol and how it impacts testosterone:

    1.) Does the human body produce its own cholesterol and if so, is there a need to supplement out bodies with more cholesterol through foods or do we manufacture enough?

    2.) I’ve heard that to boost testosterone we do need high levels of cholesterol. Many people I’ve come across says the best source are eggs? How can vegan boost their testosterone via cholesterol without any animal products?

    3.) I have learned that HDL are good fats, will HDL help boost testosterone?

    • Thea

      Ron: Happily, your body makes all of the cholesterol that it needs. So, you don’t need to supplement. You really don’t want to supplement since adding more cholesterol is generally associated with higher risk of heart attacks.

      I’m not sure how to answer you second two question except to point out this sentence from the post above: “Vegan men tended to have significantly higher testosterone levels than both vegetarians and meateaters…” So, being vegan looks to be a safe way to have higher testosterone levels naturally. You wouldn’t want more of any type of hormone than what is safe and correct for your body, would you???

    • Joseph Gonzales R.D.

      Good questions, Ron. Have you seen Dr. Greger’s video on IGF-I? I replied to someone who was also discussing testosterone. Please see our correspondences, if interested.

  • johaness vix

    this is pure bullshit show me any real research made by a reliable scientists not vegan liars!!!!

  • Luis Hernandez

    I’ve been a vegan for 5 weeks, from meat eater. I can attest to the higher testosterone levels. My libido is way up. My strength has gone up. I feel more confident, more upbeat. I love working out now; mostly doing some pretty intense bike rides, and hitting the weights too. Whole foods veganism has completely changed my life. I had a quesadilla a little while back, felt like shit for the whole day and into the next.

  • Albert Walkingstick

    As always, the devil is in the detail.

    Yes, vegan men (like me) have more testosterone than meat-eaters… BUT they also have higher sex hormone binding globulin… this means that the FREE testosterone in vegan men is no different from meat-eaters.

    Study is here –

  • Nathanael

    I remember seeing Dr. Greger quote a study claiming that those eating plant-based diets actually increased their testosterone levels as they aged. Is anyone familiar with the study he was quoting or remember which video it was? Thanks!