Several factors increase estrogen in men, ranging from body fat and certain medications to environmental chemicals and even testosterone therapy itself. The typical reference range for estradiol (the primary form of estrogen) in men is 10 to 40 pg/mL, and anything pushing levels above that range can cause symptoms like breast tissue growth, fatigue, and sexual dysfunction. Understanding what drives estrogen up is the first step toward keeping it in check.
How Men Produce Estrogen
Men don’t produce estrogen the way women do. Instead, the body converts testosterone into estradiol through a process called aromatization, driven by an enzyme called aromatase. This conversion happens in fat tissue, the testes, brain, bone, breast tissue, liver, and blood vessels. So estrogen in men is essentially a byproduct of testosterone metabolism. Anything that increases aromatase activity or provides more testosterone for the enzyme to work on will raise estrogen levels.
Body Fat Is the Biggest Driver
Fat tissue is the primary site of aromatase activity in men, which makes body composition one of the most significant factors. The more fat you carry, the more aromatase your body produces, and the more testosterone gets converted into estradiol. Research on men with obesity has confirmed that aromatase levels in subcutaneous fat are significantly higher compared to nonobese men, and that aromatase gene expression correlates positively with measures of body fat, high blood sugar, and insulin resistance.
This creates a frustrating cycle. Higher estrogen can promote further fat storage, particularly around the chest and midsection, which in turn produces more aromatase and more estrogen. Insulin resistance appears to amplify the problem, linking excess estrogen to broader metabolic issues beyond just hormone balance. Losing body fat is one of the most effective ways to reduce aromatase activity and bring estrogen back down.
Testosterone Therapy and Anabolic Steroids
This one catches many men off guard. Taking exogenous testosterone, whether through a prescription or anabolic steroids, floods the body with more raw material for aromatase to convert. The result is often a significant rise in estradiol alongside the intended rise in testosterone. The body has a natural balance between these two hormones, controlled by both testicular production and peripheral conversion. Injecting testosterone disrupts that balance by providing far more substrate than the body would normally produce.
This is why many men’s health clinics prescribe aromatase inhibitors alongside testosterone replacement therapy. These medications block the enzyme that converts testosterone to estradiol, attempting to prevent estrogen from climbing. However, the use of aromatase inhibitors in this context remains controversial and is considered off-label. If you’re on testosterone therapy and experiencing symptoms like breast tenderness or water retention, elevated estrogen from aromatization is a likely explanation.
Medications That Raise Estrogen
A wide range of prescription drugs can shift the testosterone-to-estrogen ratio in men. Some do this by directly increasing estradiol, others by blocking testosterone, and others through mechanisms that aren’t fully understood. A few of the more commonly encountered ones include:
- Spironolactone: a blood pressure and fluid-retention drug well documented to cause breast tissue growth in men at higher doses, likely through a hormonally mediated shift favoring estrogen over testosterone
- Cimetidine: a heartburn medication that can impair the body’s ability to break down estradiol into its inactive form, effectively raising circulating estrogen
- Finasteride: used for hair loss and prostate enlargement, it blocks the conversion of testosterone to another hormone, potentially leaving more testosterone available for aromatization
- Certain antidepressants: fluoxetine, paroxetine, and venlafaxine have all been linked to breast tissue changes in men
- Some blood pressure medications: amlodipine, nifedipine, verapamil, diltiazem, and captopril have been associated with hormonal shifts
- Anti-seizure and nerve pain drugs: gabapentin, pregabalin, and phenytoin appear on the list
Cancer treatments deserve a separate mention. Several chemotherapy and targeted therapy drugs, including imatinib, can reduce testosterone while raising estradiol. In one study of men treated with imatinib for leukemia, roughly one in five developed measurable breast tissue growth, with some showing modestly elevated estradiol.
Environmental Chemicals
Certain synthetic chemicals mimic estrogen in the body. These are called xenoestrogens, and the most studied is bisphenol A (BPA). Found in the lining of metal food cans, polycarbonate plastic containers, and thermal receipt paper, BPA enters the body primarily through food and beverages that have been in contact with these materials. Contaminated seafood and freshwater fish are another route, since BPA accumulates in aquatic environments from factory and landfill runoff.
Inhalation is the second most common exposure pathway. BPA is released from epoxy-based flooring, electronic equipment, and other household items manufactured with it, accumulating in household dust. Phthalates, found in fragranced personal care products, vinyl flooring, and flexible plastics, are another class of endocrine disruptors with estrogenic effects. Parabens, common preservatives in lotions and shampoos, also fall into this category.
The “BPA-free” label on products doesn’t necessarily mean safety. Replacement compounds like bisphenol S and bisphenol F are also considered endocrine disruptors. Minimizing your use of canned foods, plastic food containers (especially when heated), and heavily fragranced personal care products can reduce your overall exposure.
Zinc Deficiency
Zinc plays a regulatory role in how the body processes testosterone. In animal studies, zinc deficiency significantly increased the liver’s conversion of testosterone into estradiol while simultaneously reducing the conversion of testosterone into its other major metabolite. Zinc-deficient animals also had lower circulating testosterone to begin with, compounding the problem. The net effect was less testosterone, more estrogen, and altered hormone receptor activity in the liver.
Zinc is found in red meat, shellfish (especially oysters), pumpkin seeds, and legumes. Men who eat a limited diet, drink heavily, or have digestive conditions that impair nutrient absorption are at higher risk for deficiency.
What About Soy?
Soy foods contain isoflavones, plant compounds that are structurally similar to estrogen and can weakly bind to estrogen receptors. This has fueled persistent concerns that eating soy raises estrogen levels in men. The clinical evidence, however, does not support this. A comprehensive meta-analysis covering 41 studies and over 1,700 men found that neither soy protein nor isoflavone supplements had any significant effect on total testosterone, free testosterone, estradiol, or estrone levels. This held true regardless of the dose consumed or how long the study lasted.
The occasional case reports of feminizing effects from soy have involved extreme consumption far beyond what a normal diet would include. At typical dietary levels, soy does not appear to be a meaningful contributor to estrogen in men.
Alcohol and Liver Function
The liver is responsible for metabolizing and clearing estrogen from the body. When liver function is compromised, estrogen that would normally be broken down stays in circulation longer. Heavy alcohol use is one of the most common causes of impaired liver metabolism in men, and chronic drinking is well established as a contributor to elevated estrogen and the development of breast tissue. Alcohol also appears to increase aromatase activity directly, giving the body a double hit: more estrogen production and less estrogen clearance.
Aging
As men age, testosterone levels gradually decline while body fat tends to increase. This combination naturally shifts the testosterone-to-estrogen ratio. Aromatase activity in fat tissue doesn’t decrease with age the way testicular testosterone production does, so the conversion rate stays steady or rises even as the raw material drops. The result is a relative increase in estrogen’s influence compared to testosterone, which is one reason older men are more prone to symptoms associated with estrogen excess.