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Too Much Protein: Testosterone & Side Effects

When you’re packing on serious muscle, there’s one word that springs to mind ‘protein’, and usually lots of it. But just how effective is shoveling down too much protein, and are there any side effects from this obsession?

There just might be.

The idea that protein is the most important macronutrient is outdated information. Since that idea, several studies have come forward that shows that excess amounts of this macronutrient not only limits your gains, but can also contribute to lowering your testosterone levels.

Protein Lowers Testosterone and Muscle Growth

If you’re chugging down shake after shake, you’re risking lowering your testosterone levels.

Protein isn’t an easy nutrient for your body to digest, in fact it finds the process pretty hard – so much that taking too much of it results in an increase in cortisol in the body.

Cortisol is your body’s stress hormone, and studies have shown time and time again, that it can lead to lower T.

In this brief study involving cyclists [1], over-training caused the atheltes’ cortisol levels to rise significantly which caused their Testosterone levels to drop.

There’s a direct connection here between the stress hormone and your T-levels; the former affects the latter – and excess protein helps that happen.

In a study [2] from the Department of Kinesiology, Pennsylvania State University, subjects put on a high protein diet were analysed before and after high resistance training.

The results were shocking, showing that dietary nutrients (protein) may lower resting T concentrations by raising cortisol levels.

Too much protein also raises the amount of Sex Hormone Binding Globulin in the body (SHBG) a protein in the blood stream that binds with up 60% of your body’s free testosterone making it unusable. [3]

How Much Protein Should You Be Taking?

It’s a good question, and considering most guys aim to take in as much protein as possible the clearer we are on this issue the better.

According to research 0.77 – 0.82g to each pound of body weight appears to be the optimum amount of protein.

PRO TIP: Aim for around 0.8g/lb – keep it simple.

This was all discovered in a study done by Dr Peter Lemon at Kent State University when observing the connection between that protein has on muscle mass and strength gains [4].

His research saw that it was all about protein oxidation – this is how effectively your body synthesizes protein and builds muscle.

For the best results, the lower the oxidation, the better – and straying over this guide of 0.8g/lb created significant rises in protein oxidation.

Taking in more protein past limit doesn’t improve your muscle gain in any way, and there are more than enough studies to vouch for this. [5] [6] [7]

So after you’ve hit this limit, what’s the best way to optimize muscle gain?

More energy.

Carbohydrates and Muscle Gains

As we’ve already established, the amount of protein you take in does not determine the amount of muscles gains you’ll make after you’ve hit the required amount.

Studies have shown the best way to optimize muscle growth is to increase the amount of calories in your diet [8] – and a good way to do that is to swap that extra protein for healthy carbohydrates.

More Carbs = More Muscle?

The secret to gaining more muscle mass is calories – taking in energy from healthy sources helps lower protein oxidation and allows muscle synthesis to work at top efficiency.

And the best source to get this energy is through a good choice of carbs.

You should still be taking protein post-workout to support muscle growth [9], but don’t go overboard, you’ll have the best results having it alongside calorie-rich carbohydrates. [8]

What types of carbs should you be eating?

When we say calorie-rich, the last thing we want to you to do is go reaching for the French Fries and the Pop-Tarts – far from it.

To pack on the muscle, you’re going want to get carbs – not obese.

Next time you’re at the grocery store be sure you pick up some:

  • Potatoes
  • Yams (Sweet Potatoes)
  • Steel Cut Oats
  • Rice
  • Starchy Vegetables

Keep it as healthy as possible – for the best results carbs need to make up around 50% of your caloric intake.

A good rule of thumb is to have protein as 20% of your intake, and have good fats to make up the final 30% (eggs, avocados, olive oil etc.).carbs-protein-article

Protein Post & Pre-Workout

Never have a protein-heavy meal directly before a workout.

Nutrition is not just about what you eat. It’s when you eat it – and with protein you want to have it after your workout not before.

A study in Finland found that consuming as little as 25g of whey protein 30 minutes before a workout greatly decreased the amount of Growth Hormone and Testosterone, while also giving an increase to Insulin levels (which greatly lowers your T-count!). [10]

Too Much Protein: Testosterone & Side Effects Conclusion

Ask yourself – are you getting too much protein?

Studies have debunked the idea that a high protein diet is the best way to gain muscle, it might actually do the opposite. Your body gets stresses processing excesses of the macro and lowers the amount of T-Levels in your blood stream – affecting your gains!

This goes double if you plan on having protein-full meal directly before a workout, with Testosterone levels sinking even lower!

For optimum muscle you need to combine a solid exercise regimen with a variety of proteins, carbs and fats – with the sweet spot being around 0.8g/lb of bodyweight.

After you’ve hit this limit, chances are you’re not going to get a lot out of it, your body has all the protein it needs – that’s when you start piling on the carbs – but keep them clean, vegetables are your friends!

Your macros should be around 20% Protein, 50% Carbs, and 30% Fats.

If you’re still concerned about your T-levels, TestoFuel is your answer. As an all natural testosterone booster, TestoFuel supplies your body with the nutrients it needs to support muscle growth and overall T-Levels.


[1] Hoogeveen A. R., Zonderland M. L. Relationships between testosterone, cortisol and performance in professional cyclists. International Journal of Sports Medicine. 1996;17(6):423–428.

[2] Volek JS, Kraemer WJ, Bush JA, Incledon T, Boetes M (1997) Testosterone and cortisol in relationship to dietary nutrients and resistance exercise. J Appl Physiol (1985) 82: 49–54

[3] Anderson KE., Rosner W., Khan MS., New MI., Pang SY., Wissel PS., Kappas A.: 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;40:1761–1768

[4] Lemon PW, Tarnopolsky MA, MacDougall JD, Atkinson SA. Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. J Appl Physiol. 1992;73:767–75.

[5] Phillips S. M., Van Loon L. J. C. Dietary protein for athletes: from requirements to optimum adaptation.Journal of Sports Sciences. 2011;29(supplement 1):S29–S38. doi: 10.1080/02640414.2011.619204.

[6] Lemon P. Effects of exercise on dietary protein requirements. Int J Sport Nutr. 1998;8:426–447.

[7] Lemon P. W. Beyond the zone: protein needs of active individuals. Journal of the American College of Nutrition. 2000;19(supplement 5):513S–521S. doi: 10.1080/07315724.2000.10718974.

[8] Rozenek R, Ward P, Long S, et al. Effects of high-calorie supplements on body composition and muscular strength following resistance training. J Sports Med Phys Fit. 2002;42:340–347.

[9] Schoenfeld B. J., Aragon A. A., Krieger J. W. (2013). The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. J. Int. Soc. Sports Nutr. 10:53. 10.1186/1550-2783-10-53

[10] Hulmi JJ, Volek JS, Selänne H, Mero AA. Protein ingestion prior to strength exercise affects blood hormones and metabolism. Medicine and Science in Sports and Exercise. 2005;37(11):1990–1997.