Whey Protein Decreased Testosterone

Whey Protein and Testosterone

Written by Ben Bunting: BA, PGCert. (Sport & Exercise Nutrition) // British Army Physical Training Instructor // S&C Coach.


We all know how vital testosterone is to our sex drive and overall health. 

Whey protein and testosterone is a topic that comes up frequently in fitness circles. But not in terms of how they affect each other. 

We examine the relationship between whey and testosterone to answer the question: Does whey decrease testosterone? 

The Importance of Testosterone

Testosterone is an essential hormone in men's reproductive systems and plays an essential role in shaping male characteristics such as facial hair growth and voice projection.

Testosterone promotes muscle mass development while helping the body store and use fat. Furthermore, testosterone can boost sexual desire - hence why many refer to it as the "male sex hormone."

Testosterone levels for men typically increase throughout adolescence and reach their highest point by age 30 before declining gradually over the following years, a process known as male menopause that may lead to issues including muscle wasting, reduced energy and low libido.

Male menopause may lead to depression, anxiety and mood disorders as well - though there are strategies you can employ to ensure healthy testosterone levels throughout life.

There are countless myths surrounding testosterone, but its importance should never be discounted.

Testosterone is a vital steroid hormone produced mainly in male testicles but also to some degree by female ovaries; once produced it's secreted into the bloodstream where it travels directly to target tissues for use and fulfills its many functions.

At its optimal levels, testosterone production occurs via brain signals sent via the pituitary gland.

When production drops below this standard however, symptoms such as low libido, muscle weakness, poor bone density and reduced mental clarity may manifest themselves.

To prevent low testosterone levels, it's essential to follow a balanced diet and exercise on a regular basis.

When choosing foods rich in lean proteins and Vitamin D - such as milk and dairy products - be mindful that eating these can raise testosterone levels compared to not consuming as much dairy products. A 2021 study conducted in Taiwan discovered this correlation.

Supplements may help boost testosterone, but it's important to be mindful of their risks. Too much exogenous (prescription) testosterone could inhibit your body's natural production of it and result in infertility or other health complications.

Also, any supplements claiming to increase testosterone should only be taken on advice from a licensed healthcare professional.

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Testosterone and Muscle

The studies indicate that testosterone increases muscle mass through muscle protein synthesis.

Further research shows that the effects of testosterone on bone, connective, and neural tissues are also dose-dependent, resulting in increased muscle power, endurance, hypertrophy, and strength.

Numerous lines of evidence support the importance of androgens in mediating muscle development, including:

  • Exogenous administration potentiates gains of muscle strength and mass. 
  • That gonadotropin-releasing hormone analogs, which inhibit endogenous testosterone release, prevent gains in muscle strength and attenuate gains in muscle mass.
  • AR antagonists that inhibit the binding of endogenous testosterone to androgen receptor (AR) impair radical muscular growth when synergists are overloaded.

These findings indicate that testosterone plays a major role in the regulation of adult muscle growth as a response to mechanical load. 

What is Whey Protein?

Proteins are polymers of amino acids and play key roles in tissue repair and growth.

Protein needs increase as we age, with consumption being associated with numerous positive outcomes.

Protein-fortified products may help older adults maintain nutritional status while protecting them against age-related muscle mass loss.

Bovine milk has many nutritional and functional benefits that are regularly integrated into human diets.

Milk typically comprises water, lipids, lactose (sugar) and protein as well as smaller quantities of minerals (particularly calcium), vitamins (both water- and fat-soluble vitamins), hormones, enzymes and miscellaneous compounds).

Milk protein mainly comprises casein and whey proteins as well as other sources.

Whey is an by-product of cheesemaking; it is the liquid residue left once milk has been curdled (coagulated).

Whey liquid can then be dried out into powdered forms for sale as food supplements.

Whey protein consumption may lead to an improvement in muscle protein synthesis due to its higher leucine content and faster digestion and absorption kinetics than other protein sources.

Review papers have identified numerous other potential health benefits of whey protein consumption, including its antimicrobial, antiviral, and anticarcinogenic effects as well as improved immune, bone, and cardiovascular health benefits.

Whey Protein and Exercise 

Protein consumption is critical in optimizing muscle function during resistance exercise.

As reported by the Food and Nutrition Board of the Institute of Medicine, men aged 19-29 years (Americans and Canadians) require 56 g per day as part of their Dietary Reference Intake (DRI).

As noted above, this alone will not produce sufficient effects on intracellular essential amino acid supply, protein oxidation and muscle damage recovery during exercise, nor on increasing muscle mass and strength. 

It has been clearly demonstrated that resistance exercise training (RET) stimulates a significant increase in MPS when the protein intake is sufficient.

Thus, RET is generally considered to be a reliable strategy for improving muscle mass and function.

Protein supplementation may increase adaptive muscle response during prolonged RET.

Protein supplementation enhances protein synthesis by increasing components of anabolic hormone response such as growth hormone (GH), insulin-like growth factor-1 (IGF-1) and testosterone production.

Leucine, one of the primary amino acids present in WPH and BCAAs, has been shown to stimulate muscle protein synthesis which contributes to improved hypertrophy and functionality of muscles.

Previous studies have demonstrated that taking in whey and amino acids prior to resistance exercise leads to an improved net protein balance, and immediately post resistance exercise consuming both will provide an anabolic hormonal response.

Dietary protein supplementation before and after resistance exercise increases post-exercise protein synthesis as well as net muscle protein accumulation during recovery.

Can Whey Protein Decrease Testosterone?

This 2013 study was designed to determine the effects of whey and soy protein supplements on sex hormones in men who have undergone a heavy bout of resistance training.

The results of the main study show that soy protein supplementation for 14 days appears to reduce serum testosterone.

Whey also influences the cortisol response following a bout of intense resistance training by reducing its rise during recovery. Thus it did not reduce or decrease testosterone levels.

This study demonstrates that the type of protein used can affect the physiological response to an exercise modality that is commonly practised.

A different study published in 2007 looked at soy protein, whey protein and a soy and whey blend.

The results demonstrated that the addition of protein to the diet led to a significant increase in body weight, regardless of the source.

There were no significant differences between the groups in terms of total and free testosterone.

The Testosterone/Estradiol ratio increased across all groups and estradiol decreased.

That said, a 2019 body of research found that in adolescents, consuming either protein or glucose causes a rapid drop in plasma luteinizing hormone (LH) and testosterone.

It is not clear what the physiological significance of this response is, as there was no evidence to support testosterone's role in acute food intake regulation.

Another study saw that the T level in obese and overweight boys of peripubertal age is acutely decreased by consuming a beverage containing a mixture of glucose and protein.

This decrease could be secondary to a decrease in LH. However, this needs further investigation.


Whey protein has long been revered among bodybuilders and gymgoers for its ability to help meet protein intakes and aid recovery between sets.

Whey has numerous benefits that can help people of all ages to prevent muscular degredation, improved immunity and bone health.

Traditional advice has advised that consuming adequate levels of protein to enhance muscle growth has long been recommended; after all, this nutrient forms the basis of muscle.

But recent research has shed new light on this matter - specifically that too much protein intake can actually lower testosterone levels by inducing an insulin-like Growth Factor (IGF) spike that leads to elevated levels of Sex Hormone Binding Globulin (SHBG).

SHBG locks testosterone up and prevents its use by muscles for fuelling muscle development - meaning less effective fuelling growth!

But does whey protein really reduce testosterone?

There is conflicting evidence. Some studies state that whey consumption reduces estradiol and cortisol and in turn can enhance testosterone. Whereas some other studies have reported a significant immediate drop in testosterone levels. 

Perhaps unsurprisingly, studies have demonstrated that consumption of protein increases its absorption into muscle. 

This finding is particularly intriguing as it suggests that even though blood testosterone levels appear to decline after eating protein, this doesn't indicate an alarming downward spiral of testosterone production overall.

Instead, the amino acids contained within protein signal muscle cells to open their androgen receptors wider and absorb a large dose of testosterone from your system.

As such, do not panic, do not throw away the whey, it has many benefits and is an excellent source of protein to help support your needs.

How a Testosterone Booster Can Improve Your Testosterone Levels

Low testosterone levels can have detrimental effects on many aspects of daily living, from memory and concentration to your libido and energy levels. The good news is that natural testosterone boosters can help restore these levels.

Military Muscle is a supplement created by soldiers and athletes for individuals seeking to maximize their performance in various events, from fitness challenges to obstacle course races.

Military Muscle is an all natural testosterone booster made up of ingredients backed by research and clinical trials to ensure maximum effectiveness, distinguishing itself from similar supplements on the market.

This product includes the following ingredients:


Zinc is an essential nutrient to living a healthy life, particularly for males as it aids the production of testosterone. Furthermore, its antioxidant properties provide protection from free radical damage.

Fenugreek Seed Extract (Trigonella foenum graecum):

This plant extract is full of vitamins, minerals and fatty acids that have powerful anti-inflammatory effects and have also been proven to block aromatase enzyme activity that converts testosterone to estrogens.

Stinging Nettle Root Extract:

This plant is an effective anti-inflammatory, known to block conversion of testosterone into estrogens, while providing plenty of potassium, calcium and protein benefits.

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