Protein and Testosterone: Does Dietary Protein Intake Affect Testosterone Production? (Updated)

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Protein is easily the least demonized of the macronutrients, and when it comes to male health, people actually love it bit too much.

Especially the guys involved in any form of weight lifting, some of them consuming ridiculously high amounts of dietary protein, sometimes upwards of 50% total daily calories.

This is nothing short of disastrous for testosterone production, besides, it’s not required for optimal muscle protein synthesis either. Why? I will show few examples below.

Many men are unknowingly ingesting way too high amounts of protein which negatively impacts their hormonal environment and hinders muscular gains and overall men’s health.

Protein Intake and Testosterone Production in Men

protein intake and testosterone productionProteins are varying lengths of amino acid chains bound together with peptide bonds.

Different protein sources (collagen, meat, dairy, plant-proteins, etc) have different combinations of amino acids in their structure.

If a protein source has all the essential amino acids, it’s considered to be “complete protein”; milk, meat, and eggs being prime examples.

And when it comes to the production of testosterone and building muscle mass, the gross macronutrient intake of dietary protein in total makes a huge difference, and the type of protein consumed can also have an effect, albeit it’s not as significant as in what’s seen with total protein intake (usually measured in grams or percent of total calories).

Research over the years has shown some interesting findings about protein intake in relation to muscle gains and testosterone production.

For instance, it’s well known that chronic protein malnutrition leads to significantly lowered testosterone production and loss of muscle mass1, but we also know that protein intake at 0,8g/lb of lean mass is all you need for maximal muscle protein synthesis2,3. Even as low as 0.37g/lb is enough to maintain positive nitrogen balance in seasoned bodybuilders4.

In terms of the hormonal effects of protein, perhaps the most interesting study comes from Volek et al5. In the study, the researchers made their resistance trained subjects consume different diets with different macronutrient compositions, and examined their hormonal changes during those (low-fat, high carb, high protein, etc).

What they found was that the higher the subjects went in total protein intake, the lower their serum testosterone levels fell. Same was true for the protein/carbohydrate ratio; more protein and less carbs, resulted in significantly suppressed testosterone synthesis.

protein intake and total testosterone levels

Anderson et al6. conducted a similar study where the researchers compared the hormonal effects of high protein and high carb diets on non-trained men, total caloric intake and fat intake was kept identical on both of the diets, so the only thing that changed was the ratio of protein to carbohydrate.

Findings? Similar to as what was seen in the study by Volek et al. testosterone (and DHT) levels were significantly suppressed on a high-protein diet when compared to high-carb diet. In addition they also saw that higher protein intake resulted in lower SHBG and higher cortisol levels. Their data indicates that the only “negative” effect of a low-protein diet, would be slightly higher production of SHBG, and would you guess, research by Longcope et al7. did note that at least also in older men, lower protein intake raised SHBG production.

protein intake testosterone levels

What can also influence testosterone levels is the type of protein consumed. There isn’t much research about the subject, but at least one study has shown that animal-protein is superior to soy-protein when it comes to androgen production8. What causes this? Could be many things, such as the phytoestrogens in soy, its goitrogenic (thyroid disruptive) effect, or the different amino acid composition.

Conclusion on Dietary Protein and Testosterone

I guess it’s obvious by now that I’m not a big fan of high-protein diets.

Like many guys, I used to believe that protein was the end-all-be-all macronutrient and getting more of it would equate to more gains and better health, but this couldn’t be further from the truth.

You certainly need some protein, but nowhere near the humongous amounts that the bodybuilding and fitness industry tends to recommend (not so surprisingly they are also the ones selling you the protein tubs).

The conclusion I would draw from the above research is that high-protein diets are detrimental for testosterone production, for DHT production, and they lead to elevated levels of the catabolic stress hormone; cortisol. On the other hand, lower-protein diets can slightly increase SHBG levels, which makes testosterone less bio-availailable in the body.

In any case, I would argue that the huge drop in testosterone and DHT, accompanied with the increased stress hormone cortisol, are much more of a concern than increased SHBG, besides, consuming some fructose and supplementing with magnesium and boron are some easy ways to push that SHBG back down.

So what would be the optimal protein intake? Personally, I’d stick to around 20% of daily calories, maybe even 25-30% if you’re on a caloric deficit. I do however see no reason to ever go beyond 30%, as this would make you drop carbohydrate and fat intake too low and result in significantly suppressed testosterone production


Joaquin L, Prieto D. Differences between men and women as regards the effects of protein-energy malnutrition on the hypothalamic-pituitary-gonadal axis. Science Direct. Published May 1, 1999.
Lemon P. Effects of exercise on dietary protein requirements. Int J Sport Nutr. 1998;8(4):426-447. [PubMed]
Lemon P, Tarnopolsky M, MacDougall J, Atkinson S. Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. J Appl Physiol (1985). 1992;73(2):767-775. [PubMed]
Tarnopolsky M, Atkinson S, MacDougall J, Chesley A, Phillips S, Schwarcz H. Evaluation of protein requirements for trained strength athletes. J Appl Physiol (1985). 1992;73(5):1986-1995. [PubMed]
Volek J, Kraemer W, Bush J, Incledon T, Boetes M. Testosterone and cortisol in relationship to dietary nutrients and resistance exercise. J Appl Physiol (1985). 1997;82(1):49-54. [PubMed]
Anderson K, Rosner W, Khan M, et al. Diet-hormone interactions: protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone and cortisol and their respective binding globulins in man. Life Sci. 1987;40(18):1761-1768. [PubMed]
Longcope C, Feldman H, McKinlay J, Araujo A. Diet and sex hormone-binding globulin. J Clin Endocrinol Metab. 2000;85(1):293-296. [PubMed]
Habito R, Montalto J, Leslie E, Ball M. Effects of replacing meat with soyabean in the diet on sex hormone concentrations in healthy adult males. Br J Nutr. 2000;84(4):557-563. [PubMed]
Protein and Testosterone: Does Dietary Protein Intake Affect Testosterone Production? (Updated) was last modified: October 19th, 2017 by Ali Kuoppala

Ali Kuoppala

Ali Kuoppala is the founder of Anabolic Men, and an Independent Researcher that has been credited with organizing the findings that have helped thousands of men reach hormonal balance.
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  1. James Evans II on 05/01/2015 at 04:07

    Great article. How many grams would you
    recommend for a 6’2 200lb male at 12% body fat looking to trim down to 8%? I have been getting in 1g per pound of lean body mass, but it’s difficult consistently getting that amount.

  2. bahadur on 05/01/2015 at 07:14

    hey Ali, I am skinny but not lean. I have kinda high bf%. I am thinkin about eating 5000 calories a day to bulk up?? I am also doing heavy compound weight lifting and sprints… Is eating that amount will lead me to huge muscle gain or I will end up getting fat??

  3. Pedro Mendes de Araújo on 18/01/2015 at 22:47

    Ali, do you still recommend iodine painting? Do you still do it?

    • Denny_Lilly1 on 29/03/2017 at 14:55

      What is iodine painting? I’ve never heard of that before.

  4. ΑΝΔΡΩΜΕΑΣ on 28/02/2015 at 21:19

    you are right..the abstract say “Thus, diets low in protein in elderly men may lead to elevated SHBG levels and decreased testosterone bioactivity.”

  5. Orion Antares on 14/10/2015 at 17:52

    You linked to a study about replacing meat with soy for protein to show that animal sources are better than plant protein sources for testosterone. Does this actually show that animal proteins are better than plant proteins or just that they are better than soy proteins?

    • Martin351 on 05/04/2016 at 03:54

      animal proteins are better than plant proteins, because most plant proteins contain xeno-estrogens which completely counteract the production of testosterone. They do this by blocking the metabolic pathways in which testosterone is created but instead used to create more estrogen.

      • Orion Antares on 05/04/2016 at 22:31

        Aren’t noticable levels of phytoestrogens an issue limited to soy?

  6. Ian Rowley on 02/12/2015 at 22:25

    Hello Ali. Really good website. But I have a question about your recommendation for protein. You recommend a ‘moderate’ protein of 20-30% of calories. For a average man who needs 2500 – 3000 kcal/day, that’s 125g to 225g per day. That’s a lot. I train and weigh 180 – the usual guideline is 1g per Ib bwt, so I need 180g. Therefore your ideas are roughly in line with the conventional guidelines. But you say the ‘recommended intake’ is way too high.
    Can you explain this?

  7. […] eating enough calories, and you damn surely want to get your daily calories from around 40% carbs, 20% protein, and 40% fats for optimal […]

  8. […] are the epic bars so epic then? Well, despite their high price point, they’re exactly the kind of protein your endocrine system craves for. Animal-based. Grass-fed. And free of antibiotic, hormone, and pesticide […]

  9. dave lane on 03/04/2017 at 06:41

    Good night nurse as the late Archie Bunker said ” case closed”

  10. Paul Stacey on 26/04/2017 at 10:35

    One thing I have thought, and I’m not sure anyone else has, is… does less testosterone in the blood actually mean that our body is producing less, or that more of it is in the cells. A very high protein diet has been proven to positively impact body composition, even during overfeeding, and personally I have noticed it makes me feel better. Could it be that the high amount of protein causes the cells to increase their uptake of testosterone to drive the protein into the muscles increasing muscle mass and thus leaves less in the blood. Just a thought

  11. DDearborn on 14/03/2018 at 09:34


    “For instance, it’s well known that chronic protein malnutrition leads to significantly lowered testosterone production and loss of muscle mass, but we also know that protein intake at 0,8g/lb of lean mass is all you need for maximal muscle protein synthesis.”

    Lets take those numbers at face value…..

    That translates into 160 grams of protein for a 200 pound male. Given that humans can metabolize at most about 25 grams per serving, you would have to be taking 25 grams every three hours, 24 hours a day. Obviously at that rate, only a fraction would end up being available to the body. So who exactly is ingesting protein at those levels and rates? More to the point why are they doing so? Obviously, a sucker is still born every minute…..

    And there is another insidious side effect of mega dosing of pure protein, it screws up you cognitive capabilities……Various studies have concluded that these diets actually shrink the size of the brain……

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