Excess Protein Lowers Testosterone. Are You Consuming Too Much?


Too Much Protein Lowers Testosterone Levels

Take more protein! We see it everywhere we look. In fitness magazines, blogs and our local health supplements stores.

The general consensus in the health, fitness and bodybuilding industry is if you want to get bigger, stronger and faster, you need more protein!

Of course it is no surprise that protein powders, shakes and bars are the greatest selling nutritional supplement of all time. Even geriatric supplements in grocery stores like “Boost” sell you hard on their protein content.

Too much protein actually has an adverse effect on several areas of your health though including lowering your testosterone levels!

I am going to dive deep into the over-saturated market of protein and discuss the ramifications of what “too much” can mean to your health and wellbeing.


Excessive Protein Increases Cortisol

Protein Increases CortisolCortisol is a hormone that increases during stress whether it be mental stress such as dealing with a tough deadline at work or physically induced such as a labor intensive construction job or intense workout such as weightlifting.

It’s well known that cortisol wreaks havoc on your testosterone levels.

This is one of the reasons why ashwagandha and longjack are such great natural testosterone supplements. They help control cortisol levels and exercise induced stress.

Most people don’t realize that excessive protein can actually raise cortisol levels thereby decreasing your testosterone.

Multiple studies have been done on excessive protein intake on humans ranging from athletes to average everyday guys and the results have come back conclusive.

Too much protein raises cortisol and decreases testosterone. (1, 2, 3, 4)


Excessive Protein Increases Sex Hormone Binding Globulin (SHBG)

Sex Hormone Binding Globulin or SHBG binds to hormones and carries them throughout your body.

This is a natural and healthy process when your SHBG levels are under control but when those levels start to rise the SHBG ends up locking up your testosterone and keeping your body from being free to use it to build muscle and strength.

This is why boron is such an amazing “free testosterone” booster because it helps keep SHBG levels under control, thereby increasing your free testosterone levels.

Too much protein may increase SHBG, thereby lowering free testosterone levels. (4, 5, 6)

This is important to note because someone with low free testosterone levels can experience the same side effects associated with low testosterone even though their total testosterone count may be high.


Excess Protein Hurts Muscle Growth and Recovery

Protein increases workout recovery timeIn a randomized two trial experiment conducted at the University of Rhode Island, high protein diets results in less strength gains, lower protein synthesis and slower recovery times. (7)

The participants on a higher carb diet conversely showed bigger strength gains, better protein synthesis and faster recovery times.

They may have been getting less protein but their body was simply able to utilize it more efficiently.

In another human case study at McMaster University, 6 men were tested for muscle protein turnover during exercise and recovery.

This study found that the men on a high protein diet had higher rates of protein breakdown in their muscles and reduced protein synthesis.

The end result once again being less muscle growth than their counterparts on a higher carb diet. (8)


How Much Protein Should I Take?

How Much Protein Should I Take?How much you should take could be a whole article unto itself but instead of getting too in-depth in case studies here I’m just going to sum this up.

It’s virtually impossible for you not to get enough protein if you are consuming enough calories each day.

Rather than focusing in on one singular macronutrient such as protein, you should focus on eating a healthy and balanced diet filled with fruits, vegetables and complex carbohydrates from good sources such as beans, lentils and sprouted rice.

It is not that “high protein” diets cause testosterone issues as much as it is diets low in healthy fat and carbohydrates cause the problem.

When Dwayne “The Rock” Johnson was training for his role in Hercules for example, he ate an astounding 5,200 calories per day. 540 of those were protein which is a lot but he also ate 565 grams of carbohydrates to balance it out.

You can/should only consume so many calories in a day and the human body is synergistic by nature. When the proportion of one type of calorie increases, it means you have to decrease in another type of calorie.

And remember, it’s not just about how much you consume but how well your body can utilize what you are consuming!

Keep your focus on balance rather than a particular macronutrient and you will see your strength, muscle size and testosterone levels all increase.

Check out our article on the Best Testosterone Boosters that really work!



  1. Influence of dietary carbohydrate intake on the free testosterone: cortisol ratio responses to short-term intensive exercise training. Lane AR, Duke JW, Hackney AC. – Link
  2. Testosterone and cortisol in relationship to dietary nutrients and resistance exercise. Volek JS1, Kraemer WJ, Bush JA, Incledon T, Boetes M. – Link
  3. Relationships between testosterone, cortisol and performance in professional cyclists. Hoogeveen AR, Zonderland ML. – Link
  4. Diet-hormone interactions: protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone and cortisol and their respective binding globulins in man. Anderson KE, Rosner W, Khan MS, New MI, Pang SY, Wissel PS, Kappas A. – Link
  5. The effect of a high-protein, low glycemic-load diet versus a conventional, high glycemic-load diet on biochemical parameters associated with acne vulgaris: a randomized, investigator-masked, controlled trial. Smith RN1, Mann NJ, Braue A, Mäkeläinen H, Varigos GA. – Link
  6. Diet and Sex Hormone-Binding Globulin C. Longcope H. A. Feldman J. B. McKinlay A. B. Araujo – Link
  7. Dietary Carbohydrate and Protein Manipulation and Exercise Recovery in Novice Weight-Lifters. Lyonel Benjamin, Peter Blanpied, Linda Lamont. – Link
  8. Effect of glycogen availability on human skeletal muscle protein turnover during exercise and recovery. Howarth KR, Phillips SM, MacDonald MJ, Richards D, Moreau NA, Gibala MJ. – Link