Male hormones, collectively called androgens, are a group of steroid hormones responsible for developing and maintaining typically male physical traits. Testosterone is the most well-known, but it works alongside several other hormones that each play distinct roles in everything from muscle growth and sex drive to sperm production and bone density.
The Main Male Hormones
Testosterone is the primary androgen and the one most people think of when they hear “male hormones.” It drives the development of male sex organs before birth, triggers the changes of puberty (deeper voice, facial hair, muscle growth), and continues regulating sex drive, energy, and sperm production throughout adulthood. About 95% of testosterone in men is produced in the testes, with a small amount coming from the adrenal glands that sit on top of the kidneys.
Dihydrotestosterone (DHT) is made when the body converts roughly 10% of its daily testosterone using an enzyme called 5-alpha reductase. Despite circulating at much lower levels than testosterone, DHT is the most potent androgen. It binds to hormone receptors about twice as strongly as testosterone and releases about five times more slowly. In certain tissues like the prostate and hair follicles, local DHT concentrations can actually be ten times higher than testosterone levels. DHT is the hormone most responsible for male-pattern baldness in genetically predisposed men, and it also drives prostate growth, which is why prostate enlargement becomes more common with age.
Several other androgens serve mainly as building blocks. Dehydroepiandrosterone (DHEA) and its related form DHEA sulfate (DHEAS) are produced primarily in the adrenal glands. In men, their direct contribution to overall androgen levels is small compared to what the testes produce, but they act as precursors that tissues can convert locally into testosterone or estrogen as needed. DHEA levels peak in the twenties and thirties, then drop by about 10% per decade. By age 70 to 80, levels may be only 10% to 20% of what they were in young adulthood. Androstenedione is another precursor androgen that the body uses as raw material for making testosterone and estrogen.
Why Men Also Need Estrogen
This surprises many people, but estrogen is essential for male health. Men produce estradiol (the main form of estrogen) by converting a portion of their testosterone using an enzyme called aromatase. This conversion happens in the brain, testes, fat tissue, and other organs. Estradiol in men helps modulate sex drive, supports erectile function, and plays a role in sperm production. In the brain, estradiol synthesis increases in areas related to sexual arousal, and it also influences mood by supporting serotonin activity.
Research shows that both estrogen and testosterone are necessary for normal libido. In one notable case of a man who couldn’t produce estrogen due to a genetic enzyme deficiency, neither estrogen nor testosterone alone was enough to restore sex drive. He needed both. When estradiol levels in men drop below about 5 ng/dL, libido tends to decrease noticeably.
How the Body Regulates Male Hormones
Male hormone production is controlled by a communication loop between the brain and the testes called the hypothalamic-pituitary-gonadal (HPG) axis. It works in three steps. The hypothalamus, a small region at the base of the brain, releases gonadotropin-releasing hormone (GnRH). This signals the pituitary gland, a pea-sized gland just below it, to release two hormones: luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
LH travels through the bloodstream to the testes, where it stimulates specialized cells called Leydig cells to produce testosterone. The process begins when LH binds to receptors on Leydig cells, triggering a chain of events that moves cholesterol into the cell’s mitochondria. Four different enzymes then convert that cholesterol, step by step, into testosterone. FSH, meanwhile, targets a different group of cells in the testes called Sertoli cells. These cells create the environment and signaling molecules that sperm need to develop. Testosterone and FSH work together on Sertoli cells to trigger and maintain sperm production.
When testosterone levels rise high enough, the hypothalamus detects this and dials back its GnRH release, which reduces LH and FSH output, which in turn slows testosterone production. When levels drop, the cycle ramps back up. This feedback loop keeps hormone levels within a functional range throughout the day, though testosterone naturally peaks in the morning and dips in the evening.
Normal Testosterone Levels by Age
Testosterone levels vary significantly between individuals, and “normal” depends partly on age. Based on analysis of national health survey data from men aged 20 to 44, the middle range of testosterone levels breaks down roughly like this:
- Ages 20 to 24: 409 to 558 ng/dL
- Ages 25 to 29: 413 to 575 ng/dL
- Ages 30 to 34: 359 to 498 ng/dL
- Ages 35 to 39: 352 to 478 ng/dL
- Ages 40 to 44: 350 to 473 ng/dL
After about age 40, total testosterone declines at an average rate of about 0.4% per year. Free testosterone, the portion not bound to proteins in the blood and therefore available for the body to use, drops faster at roughly 1.3% per year. This gradual decline is a normal part of aging and doesn’t automatically mean something is wrong, but it does mean that levels at 60 or 70 will typically be meaningfully lower than at 25.
What Happens When Levels Are Too Low
Low testosterone, clinically called hypogonadism, produces different effects depending on when it occurs. If testosterone is insufficient during fetal development, the external sex organs may not develop as expected. During puberty, low levels can delay or prevent typical male development: the voice may not deepen, facial and body hair may not grow, muscle mass may stay low, and breast tissue can enlarge (a condition called gynecomastia).
In adult men, the earliest signs of low testosterone tend to be reduced sex drive, lower energy, and depression. Over time, additional symptoms can develop: difficulty getting or maintaining erections, reduced facial and body hair, loss of muscle mass, increased body fat, and decreased bone density that can progress to osteoporosis. Fertility can also be affected, since both testosterone and FSH are required for healthy sperm production. Severe cases sometimes cause concentration problems and hot flashes, similar to what women experience during menopause.
The Role of DHT in Hair Loss and Prostate Growth
DHT deserves special attention because it drives two of the most common health concerns men face as they age. In hair follicles on the scalp, DHT gradually miniaturizes the follicle, producing thinner and shorter hairs until the follicle stops producing visible hair altogether. Men with androgenic alopecia (male-pattern baldness) are genetically predisposed to have higher levels of the enzyme that converts testosterone to DHT in their scalp follicles, along with more active androgen receptors in those follicles. This is why baldness runs in families and why treatments for hair loss typically work by blocking DHT production.
In the prostate, the same enzyme is highly active, producing large amounts of DHT that stimulate prostate tissue growth. This is the primary driver behind benign prostatic hyperplasia, the non-cancerous prostate enlargement that becomes increasingly common after age 50. Prostate cancer also shows increased DHT activity, with an upregulation of the enzymes that produce it. The gene changes involved lead to uncontrolled cell growth through DHT-related pathways, which is why some prostate cancer treatments target this hormone specifically.
DHEA and Vascular Health
While DHEA is a weak androgen on its own, it has some direct effects on blood vessels that go beyond its role as a hormone precursor. DHEA activates potassium channels in blood vessel walls, enhances the production of nitric oxide (the molecule that relaxes and widens blood vessels), and helps counteract constriction caused by low oxygen. The Massachusetts Male Aging Study, which measured 17 different hormones, found that DHEAS was the only one with a clear inverse relationship to erectile dysfunction: the lower a man’s DHEAS levels, the more likely he was to experience erectile problems. This connection was especially notable in younger men, though whether low DHEAS causes the problem or results from it remains an open question.