A handful of foods and dietary patterns are linked to lower testosterone levels, but the list is shorter than most wellness sites suggest. Some of the most commonly cited culprits, like soy, have weak or no evidence behind them. The foods that do matter tend to work through specific mechanisms: blocking hormone production, spiking blood sugar, or introducing chemical contaminants that interfere with hormone signaling.
Sugar and High-Glycemic Foods
Sugar has one of the most immediate and well-documented effects on testosterone. When men consumed a standard 75-gram glucose drink (roughly equivalent to two cans of soda), their testosterone levels dropped by 25% within minutes. Levels stayed suppressed for at least two hours and hadn’t fully recovered by the end of testing. Of the men who started with normal testosterone, 15% temporarily fell into the clinically low range after the sugar load. This drop occurred regardless of whether the men were lean or overweight, and regardless of whether they had normal blood sugar control or signs of insulin resistance.
The mechanism appears to involve a direct effect on the testes rather than a simple insulin response, since the signaling hormones that normally tell the testes to produce testosterone didn’t increase to compensate. Chronic high sugar intake compounds this by promoting body fat gain, and excess fat tissue actively converts testosterone into estrogen. If you’re concerned about testosterone, consistently high sugar intake is one of the clearest dietary risks.
Licorice Root
Real licorice (not the candy flavoring) contains a compound called glycyrrhizic acid that blocks enzymes the body needs to produce testosterone. In a study of healthy young women who consumed 3.5 grams of licorice daily for two months, total testosterone dropped from about 28 ng/dL to 17.5 ng/dL, a 37% reduction. Studies in men have shown similar effects.
This isn’t a concern for most people, since licorice root consumption at these levels is uncommon in typical Western diets. But if you regularly drink licorice tea, take licorice supplements, or eat European-style licorice candy made with real glycyrrhizic acid, the effect is real and dose-dependent.
Alcohol
Alcohol lowers testosterone through multiple pathways. Ethanol itself doesn’t appear to be the direct problem. Instead, acetaldehyde, the first chemical your body produces when breaking down alcohol, is toxic to the Leydig cells in the testes that manufacture testosterone. In lab studies, blood alcohol concentrations as low as 25 mg/dL reduced testosterone production by 44%.
The relationship is dose-dependent. A single drink occasionally has minimal lasting impact. Chronic heavy drinking, on the other hand, can cause sustained testosterone suppression, testicular shrinkage, and elevated estrogen levels. Moderate drinking falls somewhere in between, with effects that vary by individual. Binge drinking, even if infrequent, produces acute testosterone drops that can last 24 hours or longer.
Trans Fats
Industrial trans fats, found in partially hydrogenated oils, fried fast food, and some packaged baked goods, are associated with lower testosterone in a dose-dependent pattern. In a study of young healthy men, those in the highest quartile of trans fat intake had total testosterone levels about 3.4 nmol/L lower than those who ate the least. That’s a meaningful difference, roughly equivalent to a 10-15% reduction depending on baseline levels.
Trans fat intake has declined significantly since many countries restricted or banned partially hydrogenated oils, but these fats still appear in some fried restaurant foods, microwave popcorn, non-dairy creamers, and imported processed goods. Checking ingredient labels for “partially hydrogenated” oils is the simplest way to avoid them.
Heavily Packaged and Processed Foods
Ultra-processed foods may lower testosterone less through their ingredients and more through their packaging. Phthalates, a class of industrial chemicals used in plastic food containers, cling wrap, and food processing equipment, leach into food and act as endocrine disruptors. Data from a large national health survey found that higher phthalate exposure from food packaging was associated with lower testosterone, particularly in men over 40. Among men 60 and older, each doubling of exposure to a common packaging-related phthalate was linked to about 8% lower total testosterone.
Other chemicals found in processed food packaging, including bisphenols and per- and polyfluoroalkyl substances (PFAS), have similar endocrine-disrupting potential. Acrylamide, a chemical that forms during high-heat processing of starchy foods, has also been shown to disrupt hormone signaling in younger populations. The direct research on ultra-processed food intake and testosterone in adults didn’t find a clear association, suggesting the packaging and processing chemicals may matter more than the food itself.
Practical steps include microwaving food in glass or ceramic instead of plastic, reducing reliance on ready-to-eat meals in plastic trays, and choosing fresh or minimally packaged options when possible.
What About Soy?
Soy is probably the most commonly cited “testosterone-lowering food” online, but the evidence doesn’t support this. A meta-analysis pooling data from multiple clinical trials found that neither soy protein nor isoflavone supplements had any significant effect on total testosterone, free testosterone, or sex hormone-binding globulin in men. The concern stems from the fact that soy contains plant estrogens (isoflavones), but these compounds are far weaker than human estrogen and don’t appear to shift male hormone levels at normal dietary intakes.
What About Flaxseed?
Flaxseed is another food frequently listed as a testosterone reducer, primarily because it contains lignans that can bind to sex hormone-binding globulin (SHBG) and theoretically reduce free testosterone. A 2023 meta-analysis of ten randomized controlled trials found no significant change in total testosterone or SHBG from flaxseed supplementation in the overall population. The one exception was men with prostate cancer, where the effects on testosterone were somewhat stronger, possibly due to their unique hormonal environment. For most people eating flaxseed for its fiber or omega-3 content, there’s little reason for concern.
Dietary Fat Balance Matters
The type of fat you eat influences testosterone production in ways that are more nuanced than “fat is good” or “fat is bad.” Your body uses cholesterol as the raw material for testosterone, and the enzyme that frees up cholesterol for hormone production preferentially works with omega-6 fatty acids. When researchers blocked the pathway that produces these omega-6 compounds in testicular cells, male hormone production dropped sharply and was rescued by adding omega-6 fatty acids back in.
This doesn’t mean you should load up on vegetable oils. It means that extremely low-fat diets, particularly those very low in omega-6 fats, could theoretically limit the raw material available for testosterone synthesis. Saturated and monounsaturated fats were much less effective at facilitating this process. A balanced intake of dietary fats from whole food sources, including nuts, seeds, eggs, fish, and moderate amounts of cooking oils, provides what the body needs without the risks associated with trans fats or excessive processed fat intake.