Is Soy Milk Bad for Men? (Debunked)

Written by: Matilda Opondo

Soy milk has multiple health benefits for both men and women. However, some men have reservations about consuming it because of certain misconceptions. 

Soy milk is a healthy nutritional choice for men. It’s rich in proteins, vitamins, and essential minerals, low in saturated fat, and a good source of fiber. 

It’s rumored to feminize and negatively affect men’s sexual functions and hormone levels.

However, an updated review of 41 studies shows that soy doesn’t affect men’s reproductive health when used in moderation. 

In this article, we’ll look at the misconceptions about soy’s effect on men to help you separate facts from myths.

We’ll also look at when soy can affect men and the benefits and risks involved in adding soy milk to your diet. 

Why People Think Soy Milk Is Bad For Men

People think soy is bad for men because of its high isoflavone content- a type of  phytoestrogen (plant estrogen). 

Phytoestrogens are structurally similar to human estrogen and can weakly mimic or block estrogen activity in the body. 

Although testosterone is the major sex hormone in men, a small amount of it is converted to estradiol, a form of estrogen. 

So it’s important to note that estrogen is found in both men and women. And soy isoflavones also have the potential to interact with men’s estrogen receptors. 

Therefore, the assumption is that drinking soy milk will raise the amount of estrogen in men and lower the amount of testosterone. 

The fear is understandable since testosterone plays an important role in men’s bodies. It is responsible for male characteristics, regulates libido, and is essential for sperm production, among other things. 

However, soy phytoestrogens are much weaker than human estrogen, so they can’t affect men's or women’s estrogen levels unless we consider:

The Consumption Of Large Quantities Of Soy Products

Phytoestrogens might be weaker than human estrogen, but they could have substantial effects if highly concentrated.

Some soy foods have higher amounts of isoflavones than others. Frequently consuming such products could lead to hormonal imbalance.

According to the USDA database, soy milk has fewer isoflavones than most soy products.



Soybean Butter


Soy Hot Dog


Soy Sauce


Soy Milk


Soy Cheese (Mozzarella)


Soy Burger


Soy Cheese (Parmesan)


Soy Cheese (Swiss)


Soy Noodles


Tofu (Silken)


Soy Yogurt


Soy Paste


Soy Fiber


Soybean Chips




Soy Protein Drink


Soy Protein Isolate




Soy Flour


That’s why it’s safer to include it in your diet than supplements with high doses of isoflavones.

Even so, you can still experience adverse reactions if you drink too much soy milk. 

The American Institute For Cancer Research claims it’s safe to consume 1 to 2 cups of soy milk daily. 

So if you’re going to drink soy milk, we suggest staying within their recommended guidelines.  

A Person’s Hormone Levels

Soy isoflavones can affect your body depending on your estrogen levels. 

For example, soy isoflavones have noticeable estrogenic effects on postmenopausal women because of their low estrogen levels.

But they might react differently to premenopausal women because their estrogen levels are high. 

Men also produce less testosterone as they age, leading to the production of less estrogen. 

So there’s a chance that soy isoflavones might interact differently among men with Androgen deficiency of the aging male (ADAM) or andropause and younger men. 

Although, it’s important to note that there’s a lack of extensive research on soy isoflavones and andropause compared to research on isoflavones and menopause. 

For more info about soy milk, check out our Soy Milk 101 video.

Analyzing The Misconceptions About Soy Milk’s Effect On Men

Let’s explore the misconceptions that gave rise to men’s soy-related fears. 

Soy and Male Fertility

In 2008, there was a study that involved 99 men in one fertility center and their three-month dietary habits. 

The sperm concentration of the men who consumed soy foods was lower by 32%. This effect was more noticeable in obese and overweight participants. 

However, it’s important to note that the sperm count of all the trial participants was still well above normal.

In 2011, there was also a unique case where a 19-year-old man experienced hormonal imbalance while on a vegetarian diet. 

He was a person with type one diabetes who reported erectile dysfunction, hypogonadism, and loss of libido allegedly due to his soy consumption. 

Although this case is popular, most people fail to mention that he consumed an extreme amount of soy. 

Therefore, applying one study based on one man’s excessive soy intake to the entire male population is not ideal.  

A recent study investigated the effect of soy phytoestrogens and dietary factors on semen quality.

It involved 1,907 participants from 14 fertility clinics and their nutritional habits for one year. 

Researchers found that phytoestrogens in soy products could potentially increase sperm quality.

The results showed that the phytoestrogens’ interaction with estrogen receptors lead to a protective effect on motile sperm count - the ability of sperms to move efficiently. 

The new study contradicts the 2008 finding but is more reliable given the larger number of fertility centers, participants, and longer study duration. 

It’s also more dependable than earlier studies that connected soy to erectile dysfunction because it had human participants. 

Animal studies don’t apply to men because humans and rodents metabolize soy differently. The animals were also exposed to high amounts of soy isoflavones. 

Despite the ongoing research, it’s evident that moderate soy intake won’t negatively affect your fertility. 

Soy and Feminization

Feminization is when a male develops female characteristics. 

As mentioned earlier, some men fear that soy might feminize them, given its high isoflavone content.

The assumption could also be due to two unique case studies where men developed gynecomastia - a condition that causes men’s breasts to swell and become larger than usual. 

The first case involved a 60-year-old man who consumed 3 quarts (12 cups) of soy milk daily for a prolonged period.

He was evaluated for gynecomastia of 6 months duration. And reported erectile dysfunction and decreased libido as well. 

A second case was reported where a 54-year-old man developed gynecomastia after drinking 1.2 liters (about 5 cups) of soy milk daily for three years. He also had erectile dysfunction and low testosterone levels. 

Both individuals only developed gynecomastia after consuming extreme amounts of soy milk for long durations.

As previously mentioned, soy phytoestrogens can affect you if frequently taken in high doses/concentrations. Especially if you’re experiencing a decrease in sex hormone levels due to aging.

Luckily, both men’s conditions improved after they stopped drinking soy milk. 

The Fertility and Sterility Journal published a study that critically evaluated clinical evidence and found that soy doesn’t have feminizing effects on men when taken in moderation.

Health Benefits Of Soy Milk For Men

Now that we’ve analyzed the misconceptions around soy and men’s health let’s look at the benefits of including soy milk in your diet. 

Reduces Risk Of Heart Disease

The CDC's health statistics on deaths caused by heart disease in 2020 showed that men were more affected than women.


% of Deaths

Male %

Female %

American Indian or Alaska Native








Black (Non-Hispanic)




Native Hawaiin or Other Pacific Islander




White (Non-Hispanic)








More Than One race




Although several issues can affect one's heart health, high cholesterol is one of the significant risk factors. 

Fortunately, the National Center for Complementary and Integrative Health claims that soy might help lower bad cholesterol levels (LDL) and increase good cholesterol levels (HDL).

A meta-analysis of 11 clinical trials also found that soy isoflavones have cholesterol-lowering effects. 

Moreover, soy milk contains dietary fiber and polyunsaturated fats, which are great for lowering cholesterol.

Therefore, including soy milk in your diet might be a great way to support your heart health. 

Great For Bone Health 

Osteoporosis weakens bones making them more fragile.

Although it’s viewed as a ‘woman’s disease,’ the NIH Osteoporosis and Related Bone Diseases Center claims it poses a significant threat to millions of men. 

A review of thirty-six studies found that soy isoflavones can help prevent osteoporosis and improve bone health. 

Soy milk also contains calcium which is essential for healthy bones and teeth.

Protects Against Hormonal Cancers

The misconception that soy increases one’s cancer risk came from animal studies. However, such claims are inaccurate since humans process isoflavones differently. 

The American Cancer Society refuted this belief, and updated studies show that soy may lower men’s risk of prostate cancer

A controlled study published in The American Association For Cancer Research Journal also found that soy isoflavones could potentially slow down prostate cancer progression in the early stages. 

Although breast cancer is mostly found in women, 1 out of every 100 breast cancer diagnosed is found in men. Fortunately, research shows that soy might improve resistance to breast cancer. 

Additionally, a study in the Journal of the American Medical Association (JAMA) found that cancer survivors who added soy to their diet had a lower risk of cancer recurrence and death. 

Manages Blood Pressure And Blood Sugar Levels

According to the CDC, more men have high blood pressure than women. 

A greater percentage of men (50%) have high blood pressure than women (44%).

Research shows that soy milk can help regulate your blood pressure if you have mild to moderate hypertension. 

A study on soy components and diabetes found that soy could reduce the risk of type 2 diabetes. The study suggested that soy can help manage blood glucose levels.

Overall, soy milk is an excellent choice for men looking to manage their blood pressure or diabetic condition. 

Great For Weight Management 

Soy is low in saturated fats and contains dietary fiber and protein, which are beneficial for weight loss

A recent study also found that men who supplemented with soy protein during resistance training had a similar increase in strength and muscle mass as those who supplemented with whey and animal protein. 

Meta-analysis showed that supplementing resistance exercise training with whey or soy protein resulted in significant increases in strength but found no difference between groups.

International Journal of Sport Nutrition and Exercise Metabolism

Lowers Inflammation

Inflammation occurs when the body attempts to heal itself. 

However, prolonged inflammation can increase the risk of heart disease, diabetes, cancer, and rheumatoid arthritis. 

Research shows that soy milk has inflammatory properties. Therefore, it might help reduce the risk of chronic diseases by managing the body’s inflammation levels. 

Can Help With Some Low Testosterone Symptoms

Aside from reduced erectile function and sex drive, men with low testosterone levels experience symptoms such as:

how soy milk helps low testosterone symptoms

Loss Of Muscle Mass

As mentioned earlier, soy is great for bone health because of its isoflavone and calcium content. You can also include soy milk in your diet if you are resistance training and wish to gain muscle mass. 

Poor Memory And Focus

The B vitamins in soy milk are great for brain health. They can improve cognitive performance and reduce the risk of incident dementia.  

Fatigue And Low Energy Levels

Soy has vitamins and minerals that can help reduce fatigue and boost your energy levels.  

Mood Swings And Depression

Soy milk contains tryptophan and magnesium, which help the body produce serotonin - a natural mood stabilizer. 


As previously mentioned, soy milk is great for weight management. Consider including it in your weight loss plan/diet.

Loss Of Body Hair

Research shows that frequent consumption of soy milk might provide protective effects against androgenic alopecia - the most common form of hair loss in men. 

A recent study also showed that black soybean extracts could promote hair growth.

Health Risks Associated With Soy Milk 

There are some potential health risks associated with soy milk, particularly if you drink a lot of it.

Health Risks Associated With Soy Milk


Aside from the rare hormonal changes, excess soy consumption might trigger migraines. 

The American Academy Of Neurology published a case where a 57-year-old man experienced migraines because of his excess isoflavone intake but got better after reducing his dosage. 

Allergic Reactions

You should avoid soy milk if you have soy allergies.

Consult your doctor before consuming soy products for the first time because soy can cause reactions like swelling, stomach upsets, diarrhea, and vomiting. 

In rare cases, you could even trigger a life-threatening reaction called anaphylaxis

Thyroid Health

Soy milk is safe for people with enough iodine, normal thyroid function, and sufficient estrogen levels. 

However, its excess intake might affect you depending on your thyroid health or estrogen levels. 

Soy isoflavones are especially risky for people with hypothyroidism since they might interfere with the absorption of thyroid medication.

Ensure you consult your endocrinologist if you have thyroid issues but are thinking of including it in your diet. 

Nutritional Deficiencies

Soy contains antinutrients like phytic acid, which can block the absorption of essential minerals. 

You can safely consume soy milk if you have healthy levels of essential minerals.

However, you should avoid it if you have low niacin, calcium, zinc, magnesium, and iron levels. Unless your doctor clears you of the risk of developing nutritional deficiencies.

Soy Milk is Fine For Most Men

New and updated research debunk the misconceptions around soy milk and men’s health. 

Soy milk is good for men as long as it’s taken in moderation. Sticking to the recommended daily amounts of isoflavones or soy milk ensures you enjoy all of soy's health benefits.

The only people who should avoid soy milk are those with soy allergies, thyroid issues, and mineral deficiencies unless their doctor or endocrinologist clears them.

About the Author

Matilda is a freelance content writer who enjoys writing about health and wellness. When she is not writing she loves spending time with her daughter and working on her fitness goals.