Men naturally produce estrogen, and it plays essential roles in bone health, brain function, and cardiovascular protection. The primary source is an enzyme called aromatase, which converts testosterone into estrogen throughout the body. Problems arise when this conversion tips out of balance, pushing estrogen levels too high relative to testosterone. Several factors can accelerate that shift, from body fat and aging to liver disease and environmental chemicals.
How Men Produce Estrogen
Unlike women, who produce most of their estrogen in the ovaries, men generate estrogen indirectly. An enzyme called aromatase takes testosterone and androstenedione (another androgen) and converts them into estrogen through a series of three chemical reactions. This happens inside fat cells, bone, skin, the brain, and other tissues. Every man with circulating testosterone is also producing some estrogen as a byproduct of that conversion. In healthy men, estradiol (the most potent form of estrogen) typically sits around 20 to 30 pg/mL, a fraction of what premenopausal women produce but enough to serve important biological functions.
The key point: estrogen in men isn’t coming from an outside source in most cases. It’s being manufactured from your own testosterone supply. Anything that increases aromatase activity or decreases the body’s ability to clear estrogen will tilt the balance.
Body Fat Is the Biggest Driver
Fat tissue is one of the most active sites of aromatase activity in men. The more adipose tissue you carry, the more aromatase is available to convert testosterone into estradiol. This creates a self-reinforcing cycle: increasing body fat raises estrogen, which promotes further fat storage (particularly around the midsection), which raises estrogen further. Meanwhile, testosterone drops because more of it is being converted rather than remaining available.
This pattern is well documented in research on obese men. As fat mass increases, aromatase activity rises, irreversibly converting testosterone to estradiol. The result is simultaneously lower testosterone and higher estrogen, a combination that can produce noticeable symptoms. Visceral fat, the deep abdominal fat surrounding organs, is particularly active in this conversion. Losing even a moderate amount of body fat can meaningfully shift the ratio back toward normal.
How Aging Changes the Balance
Testosterone production gradually declines as men age, typically dropping about 1% per year after age 30. But estrogen doesn’t fall at the same rate, which means the ratio between the two hormones shifts. A protein called sex hormone-binding globulin (SHBG) adds another layer of complexity. SHBG binds to both testosterone and estrogen in the bloodstream, controlling how much of each hormone is “free” and active in tissues.
In men, SHBG levels increase linearly with age. Higher SHBG binds more testosterone, reducing the amount available to tissues. The net effect is that aging men often have less free testosterone circulating while their estrogen levels hold relatively steady or even rise, especially if body fat has increased over the years. This gradual shift is why symptoms like reduced libido, fatigue, and breast tissue changes become more common in older men.
Liver Disease and Estrogen Clearance
The liver is responsible for breaking down and clearing roughly 70% of sex hormones from the body. It also produces SHBG and contains its own aromatase enzymes. When the liver is damaged, particularly in conditions like cirrhosis, several things go wrong at once: aromatase activity in the liver increases, more testosterone gets converted to estrogen in other tissues due to changes in blood flow (portosystemic shunting), and the liver’s ability to metabolize and remove excess estrogen drops sharply.
Men with chronic liver disease commonly develop elevated estrogen levels. This is one reason gynecomastia (breast tissue enlargement) and testicular shrinkage are recognized physical signs of advanced liver disease. Even moderate liver dysfunction from heavy alcohol use can impair estrogen clearance enough to shift hormone levels.
Environmental Chemicals That Mimic Estrogen
Certain synthetic chemicals can bind to estrogen receptors in the body and activate them, effectively mimicking estrogen’s effects. These are called xenoestrogens. The most studied is bisphenol A (BPA), an industrial chemical found in polycarbonate plastics, epoxy resin linings in cans, PVC products, and thermal receipt paper. BPA binds to both types of estrogen receptors in the body. Its estrogenic potency is roughly 10,000 to 100,000 times weaker than natural estradiol on a molecule-for-molecule basis, but chronic low-level exposure is widespread.
In both animal and human studies, BPA exposure has been linked to decreased sperm production, changes in prolactin release, and disruption of androgen metabolism. Other xenoestrogens include phthalates (found in flexible plastics and personal care products), parabens (preservatives in cosmetics), and certain pesticides. The cumulative effect of daily exposure to multiple xenoestrogens is still being studied, but reducing contact with these chemicals, particularly from heated plastics and food packaging, is a reasonable precaution.
What About Soy and Phytoestrogens?
Soy contains compounds called isoflavones that have a weak ability to interact with estrogen receptors, which has fueled persistent concerns about soy raising estrogen in men. The clinical evidence, however, doesn’t support this. An expanded meta-analysis of clinical studies found that neither soy protein nor isoflavone intake affects total testosterone, free testosterone, estradiol, or estrone levels in men, regardless of dose or study duration. Eating tofu, edamame, or drinking soy milk in normal dietary amounts does not meaningfully change male hormone levels.
Medications and Testosterone Therapy
Some medications and supplements can raise estrogen as a side effect. The most common scenario involves testosterone replacement therapy itself. When you introduce exogenous testosterone, aromatase converts a portion of it into estradiol, just as it would with naturally produced testosterone. Higher doses mean more raw material for conversion, which is why men on testosterone therapy are often monitored for rising estrogen levels. If estradiol climbs too high, it can cause breast tenderness, water retention, and mood changes.
Anabolic steroids used for bodybuilding carry the same risk, often at a more extreme level because the doses involved far exceed therapeutic amounts. Some hair loss medications and antiandrogen drugs can also shift the testosterone-to-estrogen ratio. When testosterone therapy causes problematic estrogen elevation, clinicians sometimes use aromatase inhibitors, medications that block the conversion enzyme directly. Third-generation versions like anastrozole and letrozole are potent and highly specific to aromatase without disrupting other hormone pathways.
Signs of Elevated Estrogen in Men
High estrogen doesn’t always produce obvious symptoms, especially when the elevation is mild. As levels climb, the most recognizable signs include gynecomastia (growth of breast tissue, not just chest fat), breast tenderness or nipple sensitivity, erectile dysfunction, reduced libido, and infertility. Some men also notice increased water retention, fatigue, and mood disturbances.
These symptoms overlap heavily with low testosterone, which makes sense because the two conditions frequently occur together. When a man’s testosterone is being converted to estrogen at an accelerated rate, he experiences the effects of both low testosterone and high estrogen simultaneously. Diagnosis requires blood work, specifically measuring estradiol alongside total and free testosterone. Estradiol is typically checked in men who present with breast-related symptoms or who are on testosterone therapy.
What Lowers Estrogen Naturally
Because aromatase activity in fat tissue is the primary modifiable source of estrogen in men, reducing body fat is the single most effective natural strategy. Even a 10 to 15% reduction in body weight can significantly lower estradiol and improve the testosterone-to-estrogen ratio. Resistance training appears particularly beneficial, both by reducing fat mass and by supporting testosterone production.
Limiting alcohol intake matters too, since alcohol both increases aromatase activity and burdens the liver’s ability to clear estrogen. Reducing exposure to xenoestrogens by avoiding microwaving food in plastic, choosing BPA-free containers, and limiting processed food contact with plastic packaging can lower your chemical estrogen burden over time. Sleep quality and stress management also play supporting roles, as chronic sleep deprivation and elevated cortisol can suppress testosterone production, indirectly worsening the ratio.