Yes, men naturally produce estrogen, and it plays a surprisingly important role in male health. Every man’s body converts a portion of its testosterone into estrogen through an enzyme called aromatase, which is active in the testes, fat tissue, brain, bone, and several other organs. Healthy adult men typically have estradiol (the most potent form of estrogen) levels between 20 and 50 pg/mL, a fraction of what women produce but enough to influence everything from bone strength to sexual function.
How Men Produce Estrogen
The process starts with testosterone and other androgens. An enzyme called aromatase, found throughout the body, strips a carbon atom from these hormones and reshapes them into estrogens. Specifically, aromatase converts testosterone into estradiol, the primary and most active estrogen. It also converts a precursor hormone called androstenedione into a weaker form of estrogen called estrone. So men don’t produce estrogen independently of testosterone. The two hormones are directly linked: estrogen is literally made from testosterone.
Where Estrogen Is Made in Men
The testes are the primary production site. Inside them, estrogen is synthesized in Leydig cells (which also make testosterone), Sertoli cells (which support sperm development), and even in maturing sperm cells themselves. But a significant share of male estrogen comes from outside the testes. Fat tissue is the largest extra-gonadal source of estrogen in men, and its contribution grows with age and body weight. The brain, bone, liver, adrenal glands, skin, blood vessels, intestines, and spleen all produce small amounts of estradiol locally, where it acts on nearby cells rather than circulating through the bloodstream.
Why Men Need Estrogen
Bone Health
Estrogen is actually the dominant hormone controlling bone breakdown in men, even more so than testosterone. Research on male bone metabolism found that estrogen played the major role in regulating bone resorption, while both estrogen and testosterone contributed to maintaining bone formation. Men with very low estrogen levels are at higher risk for progressive bone loss, which is one reason doctors pay attention to estrogen and not just testosterone when evaluating skeletal health in aging men.
Sexual and Reproductive Function
Estradiol helps regulate libido, erectile function, and sperm production in men. Inside the testes, estrogen modulates spermatogenesis at every stage, from the hormonal signals that initiate sperm development down to the maturation of individual sperm cells in the epididymis. In men with low testosterone, supplemental estradiol has been shown to increase sexual desire. One particularly revealing case involved a man who lacked the aromatase enzyme entirely and also had low testosterone. Neither estrogen nor testosterone alone was enough to restore his libido. He needed both, suggesting that estrogen plays an irreplaceable role in male sexual desire.
Brain Function and Mood
Estrogen influences cognition, mood, motor coordination, and pain sensitivity in both sexes. In the brain, locally produced estradiol appears to protect neurons from damage. Animal models of stroke show that traumatic injury can activate the aromatase system in the brain, triggering a burst of local estrogen production that helps shield brain cells. Estrogen’s neuroprotective effects extend to conditions like Parkinson’s and Alzheimer’s diseases, though the precise mechanisms are still being studied.
Heart Health
Low estrogen in men is associated with increased risk of coronary artery disease. A study comparing men with heart disease to healthy controls found that the heart disease group had significantly lower levels of both testosterone and estrogen. The relationship was strong enough that the researchers concluded estrogen deficiency, alongside testosterone deficiency, is directly associated with the arterial damage that leads to heart attacks.
What Happens When Estrogen Is Too High
While men need estrogen, too much creates problems. Elevated estrogen levels can cause gynecomastia (breast tissue enlargement), erectile dysfunction, and infertility. The most common driver of excess estrogen in men is excess body fat. Aromatase expression is directly proportional to fat mass, meaning the more adipose tissue a man carries, the more testosterone gets converted into estrogen. This creates a self-reinforcing cycle: higher aromatase activity leads to more estrogen, which promotes further fat accumulation, which increases aromatase activity even more. This excessive conversion is considered the underlying reason for obesity-related infertility in men, because it simultaneously raises estrogen and depletes testosterone.
How Estrogen Changes With Age
The pattern of estrogen levels across a man’s lifespan is not as straightforward as the well-known decline in testosterone. Some studies report estrogen levels dropping with age, while others find them holding steady or even increasing. The explanation for this inconsistency likely comes down to body composition. Testosterone declines with age in most men, which would reduce the raw material for estrogen production. But older men also tend to carry more body fat, which increases aromatase activity. The net effect depends on the individual. Whole-body aromatization rates are measurably higher in older men, so a man who gains significant weight as he ages may maintain or increase his estrogen levels even as his testosterone falls. A leaner older man might see both hormones decline together.
This interplay is one reason hormonal health in aging men is more complex than a single testosterone number. The balance between testosterone and estrogen matters as much as the absolute level of either one, influencing bone density, cardiovascular risk, body composition, and sexual function simultaneously.