Several common foods can lower testosterone, though the effect varies widely depending on how much you eat and how often. The biggest offenders backed by research are sugar, trans fats, and alcohol. Others, like soy and flaxseed, have a more complicated reputation than they deserve. Here’s what the evidence actually shows for each one.
Sugar and Refined Carbohydrates
Sugar causes one of the fastest and most dramatic testosterone drops of any food. In healthy men, consuming a standard glucose load (about 75 grams, roughly equivalent to two cans of soda) triggers an average 18% reduction in total testosterone. Levels start falling within 20 minutes, bottom out around the one-hour mark, and most men still have testosterone below their baseline two hours later.
This isn’t a one-time quirk. The drop is large enough that a man with normal testosterone could temporarily test in the low range after a sugary meal. Over time, diets consistently high in sugar and refined carbohydrates contribute to insulin resistance and weight gain, both of which are strongly linked to chronically lower testosterone. If any single dietary change makes the biggest difference, cutting back on added sugar is a strong candidate.
Trans Fats
Trans fats are among the most clearly harmful dietary fats for testosterone. In a study of young, healthy men, those in the highest quarter of trans fat intake had 15% lower total testosterone and 4% smaller testicular volume compared to men who ate the least. The same high-intake group also had 37% fewer total sperm.
Trans fats also reduced calculated free testosterone (the portion your body can actually use) in a dose-dependent pattern, meaning the more men ate, the lower their levels dropped. Men in the top quarter of intake had total testosterone about 3.4 nmol/L lower than those in the bottom quarter. While many countries have restricted artificial trans fats, they still appear in some fried foods, packaged baked goods, and margarine. Checking ingredient labels for “partially hydrogenated oil” is the simplest way to avoid them.
Alcohol
Alcohol suppresses testosterone through several overlapping mechanisms. It acts directly on the cells in the testes that produce testosterone, and the breakdown product of alcohol, acetaldehyde, adds further damage. The enzymes your body uses to process alcohol also compete for the same chemical helpers needed to manufacture testosterone, essentially diverting resources away from hormone production.
On top of that, alcohol raises cortisol, a stress hormone that directly inhibits testosterone-producing cells. It also increases levels of natural opioid-like compounds in the testes that further suppress testosterone release. Occasional moderate drinking has a relatively minor and temporary effect, but heavy or chronic drinking creates a sustained hormonal hit that compounds over time.
Vegetable Oils High in Omega-6 Fats
This one comes with nuance. Omega-6 fats, found abundantly in sunflower oil, soybean oil, corn oil, and other common cooking oils, can interfere with testosterone production at high intakes. In animal research, sunflower oil supplementation reduced the activity of multiple enzymes involved in making testosterone, including those responsible for the earliest and final steps of the process.
In the same human study that flagged trans fats, omega-6 intake was inversely related to testicular volume, meaning higher intake correlated with smaller testes. The practical takeaway isn’t to eliminate these oils entirely, since some omega-6 is essential. The problem is the modern diet’s ratio: most people consume far more omega-6 than omega-3. Replacing some vegetable oil use with olive oil, and eating more fatty fish for omega-3s, shifts the balance in a more favorable direction. In that same study, omega-3 intake was positively associated with testicular volume.
Processed Meat
Processed meats like hot dogs, bacon, sausages, and deli meats show a consistent association with worse reproductive markers. In a study of young men, those who ate the most processed red meat had 78 million fewer total sperm than those who ate the least. The trend in testosterone was also downward, with total testosterone dropping from 21.5 nmol/L in the lowest intake group to 19.3 nmol/L in the highest, though this particular trend didn’t reach statistical significance on its own.
The likely culprits are the additives, preservatives, and saturated fats concentrated in processed meats rather than the protein itself. Unprocessed red meat did not show the same pattern, which suggests it’s the processing, not the animal protein, that matters.
Licorice Root
Real licorice (not the candy flavored with anise) contains a compound called glycyrrhizic acid that blocks two enzymes your body needs to produce testosterone. A study published in the New England Journal of Medicine found that men who consumed 7 grams of licorice daily (containing 0.5 grams of glycyrrhizic acid) experienced a measurable drop in testosterone within just four days. Testosterone recovered after they stopped.
Most people don’t eat enough real licorice for this to matter, but it’s worth knowing if you regularly consume licorice root tea, supplements, or imported licorice candy that contains actual glycyrrhizic acid rather than artificial flavoring.
Mint
Spearmint tea has been shown to lower free testosterone in women with excess body hair, where it’s sometimes used as a mild anti-androgen treatment. In one clinical trial, spearmint tea significantly decreased free testosterone while leaving total testosterone largely unchanged.
The catch is that most of this research has been conducted in women, and the doses involved are relatively high (multiple cups of tea daily). There’s limited direct evidence in men. If you drink the occasional mint tea, it’s unlikely to move the needle. Regular, heavy consumption is a different question, and the existing evidence at least suggests caution.
Soy: Less Harmful Than Its Reputation
Soy is probably the most feared “testosterone killer” online, but meta-analyses consistently show that soy protein and its plant estrogens do not significantly affect testosterone levels in men. The compounds in soy are structurally similar to estrogen, which is where the concern comes from, but they bind to estrogen receptors far more weakly than actual estrogen does.
That said, the clinical trials included in these analyses were relatively short, averaging around 74 days. Extreme consumption over long periods is a different matter. There are rare case reports of men consuming very large amounts of soy (more than a liter of soy milk daily for months) and experiencing hormonal changes. Normal dietary amounts, like tofu a few times a week or soy milk in your coffee, appear to be fine.
Flaxseed: Mixed but Mostly Reassuring
Flaxseed contains lignans, compounds that can theoretically bind to testosterone and increase its excretion, and may stimulate production of a protein that locks up testosterone so your body can’t use it. In lab settings, this sounds concerning. In practice, a meta-analysis of six randomized trials found no significant change in either that binding protein or total testosterone from flaxseed supplementation.
Interestingly, subgroup analysis showed that in men specifically, flaxseed supplementation was actually associated with a slight increase in total testosterone. The anti-androgen effects appear more relevant in women with hormonal conditions like PCOS. For most men eating moderate amounts of flaxseed for the fiber and omega-3 benefits, testosterone disruption is unlikely.
Dairy and Estrogen Exposure
Commercial cow’s milk contains naturally occurring estrogens, and an estimated 60 to 80% of dietary estrogen exposure in Western diets comes from milk and dairy products. The primary estrogen in milk is estrone, with about 90% of it in a conjugated form that has relatively high oral bioavailability, meaning your body can absorb and use it.
The concentrations are small in absolute terms. Whole milk contains roughly 0.13 ng/mL of estrone and 0.02 ng/mL of estradiol. Butter concentrates these hormones significantly, reaching 1.47 ng/g of estrone. Whether these amounts are enough to meaningfully shift male hormone balance is still debated, but epidemiological studies have found associations between high dairy consumption and increased rates of testicular and prostate cancers. The practical move isn’t necessarily eliminating dairy but being aware that very high intake, particularly of full-fat dairy products, adds a measurable estrogen load.
The Bigger Picture
Individual foods rarely tank your testosterone on their own. What matters more is dietary patterns. A diet built around processed foods, sugary drinks, fried items, and excessive alcohol creates overlapping insults: insulin spikes that suppress testosterone acutely, trans fats that reduce it chronically, excess calories that drive body fat accumulation (which converts testosterone to estrogen), and nutrient gaps that starve the enzymes responsible for hormone production. Replacing the worst offenders with whole foods, healthy fats, and adequate protein addresses most of these pathways at once.