Testosterone is a sex hormone that plays a powerful role in health.
Maintaining healthy levels of testosterone is important for gaining muscle mass, improving sexual function and boosting strength (1Trusted Source).
Not to mention, alterations in testosterone levels have been associated with a number of health conditions, including obesity, type 2 diabetes, metabolic syndrome and heart problems (2Trusted Source).
While many factors are involved in the regulation of testosterone, a healthy diet is key to keeping levels in check and preventing them from dropping too low.
Here are 8 foods that lower testosterone levels you may want to watch out for.
1. Soy and Soy-Based Products
Some research shows that regularly eating soy products like edamame, tofu, soy milk and miso may cause a drop in testosterone levels.
For example, one study in 35 men found that drinking soy protein isolate for 54 days resulted in decreased testosterone levels (3Trusted Source).
Soy foods are also high in phytoestrogens, which are plant-based substances that mimic the effects of estrogen in your body by altering hormone levels and potentially reducing testosterone (4Trusted Source).
Though human-based research is limited, one rat study showed that consuming phytoestrogens significantly decreased testosterone levels and prostate weight (5Trusted Source).
However, other research found conflicting results, suggesting that soy-based foods may not have as much of an impact as these isolated soy components.
In fact, one large review of 15 studies found that soy foods had no effect on testosterone levels in men (6Trusted Source).
Further research is needed to understand how soy products as a whole may influence testosterone levels in humans.
Perhaps most well-known for its powerful stomach-soothing properties, some research suggests that mint could cause a dip in testosterone levels.
In particular, spearmint and peppermint — two herbs that hail from the mint family of plants — have been shown to have a direct impact on testosterone.
One 30-day study in 42 women showed that drinking spearmint herbal tea daily caused a significant decline in testosterone levels (7Trusted Source).
Meanwhile, another animal study noted that drinking peppermint tea altered hormone levels in rats, leading to a decrease in testosterone, compared to a control group (9Trusted Source).
However, most research on mint and testosterone focuses on women or animals.
High-quality human studies focusing on both genders are needed to assess how mint affects testosterone levels in both men and women.
3. Licorice Root
Licorice root is an ingredient commonly used to sweeten candies and beverages.
It’s also a popular natural remedy in holistic medicine and often used to treat everything from chronic pain to persistent coughing (10Trusted Source).
In recent years, several studies have found that licorice may also influence hormone levels, potentially leading to a decline in testosterone over time.
In one study, 25 men consumed 7 grams of licorice root daily, which caused a 26% drop in testosterone levels after just one week (11Trusted Source).
Another small study showed that licorice may reduce testosterone levels in women as well, reporting that 3.5 grams of licorice daily decreased testosterone levels by 32% after just one menstrual cycle (12Trusted Source).
Keep in mind that this applies to licorice root rather than licorice candy, which often doesn’t contain any licorice root.
4. Vegetable Oil
Many of the most common vegetable oils, including canola, soybean, corn and cottonseed oil, are loaded with polyunsaturated fatty acids.
These fatty acids are usually classified as a healthy source of dietary fat, but they may also decrease testosterone levels, as several studies have suggested.
One study in 69 men showed that frequently consuming polyunsaturated fats was associated with significantly lower testosterone levels (13Trusted Source).
Another study in 12 men looked at the effects of diet on testosterone levels after exercise and reported that polyunsaturated fat intake was linked to lower levels of testosterone (14Trusted Source).
However, recent research is limited, and most studies are observational with a small sample size.
More high-quality studies are needed to examine the effects of vegetable oils on testosterone levels in the general population.
Flaxseed is packed with heart-healthy fats, fiber and various important vitamins and minerals.
In addition, some research shows that it may cause a decrease in testosterone levels in certain populations.
In one small study in 25 men with prostate cancer, supplementing with flaxseed and decreasing overall fat intake was shown to significantly reduce testosterone levels (18Trusted Source).
Similarly, a case study reported daily flaxseed supplements decreased testosterone levels in a 31-year-old woman with polycystic ovary syndrome, a condition characterized by increased male hormones in women (16Trusted Source).
However, more large-scale studies are needed to further evaluate the effects of flaxseed on testosterone levels.
6. Processed Foods
Plus, some studies have found that regularly consuming trans fats from sources like processed foods could decrease testosterone levels.
For example, one study in 209 men showed that those who consumed the highest amounts of trans fats had 15% lower levels of testosterone than those with the lowest intake.
While enjoying the occasional glass of wine with dinner has been linked to health benefits, studies show that excessive alcohol intake could cause testosterone levels to plummet — especially in men (26Trusted Source).
A study in 19 healthy adults showed that consuming 30–40 grams of alcohol per day, which equates to about 2–3 standard drinks, decreased testosterone levels in men by 6.8% over three weeks (27Trusted Source).
Another study reported that acute alcohol intoxication was associated with increased testosterone in women but decreased levels in men (28Trusted Source).
However, the evidence isn’t completely clear-cut when it comes to the effects of alcohol on testosterone.
In fact, both human and animal studies have had mixed results, with some research indicating that alcohol could actually increase testosterone levels in certain cases (29Trusted Source, 30Trusted Source).
Further research is still needed to understand how different doses of alcohol affect testosterone levels in the general population.
Additionally, some studies suggest that certain types of nuts may decrease testosterone levels.
One small study in 31 women with polycystic ovary syndrome showed that walnuts and almonds increased levels of sex hormone binding globulin (SHBG) by 12.5% and 16%, respectively (32Trusted Source).
SHBG is a type of protein that binds to testosterone, which can lead to a decrease in the levels of free testosterone in your body (33Trusted Source).
Despite these findings, more research is needed to determine how certain types of nuts may impact testosterone levels.
The Bottom Line
Changing up your diet is one of the most effective ways to maintaining healthy testosterone levels.
If you’re concerned about low testosterone levels, swapping out these testosterone-lowering foods and replacing them with healthy, whole food alternatives can keep levels in check and enhance your overall health.