DHT (dihydrotestosterone) is a powerful sex hormone responsible for developing male sex characteristics before birth, driving changes during puberty, and maintaining several tissues throughout adult life. It’s made from testosterone by an enzyme called 5-alpha-reductase, and despite circulating in relatively small amounts in the bloodstream, DHT can reach concentrations up to ten times higher than testosterone in the specific tissues where it acts.
How Your Body Makes DHT
DHT isn’t produced in one central location like many hormones. Instead, the enzyme 5-alpha-reductase converts testosterone into DHT right at the tissues that need it, making it what scientists call a paracrine hormone. There are three versions of this enzyme, but type 2 does most of the heavy lifting. It sits in the skin, hair follicles, prostate, and reproductive tissues, converting testosterone on site. The liver also produces some DHT, but only small amounts enter general circulation. This local production system means DHT levels in a given tissue can be far higher than what a blood test would suggest.
Fetal Development and Puberty
DHT’s most critical job happens before birth. During fetal development, circulating testosterone gets converted to DHT, which then directs the formation of external male genitalia. Without adequate DHT at this stage, these structures don’t develop typically. Children born with 5-alpha-reductase deficiency, a genetic condition that blocks DHT production, illustrate this clearly: their internal reproductive organs form normally (testosterone handles that part), but external anatomy is often underdeveloped or ambiguous at birth.
At puberty, DHT picks up where it left off. It drives further growth of the penis and scrotum and is the primary hormone behind facial hair, body hair, pubic hair, and prostate growth. Testosterone gets much of the credit for puberty, but many of the visible changes people associate with male adolescence are actually DHT’s doing.
DHT’s Role in Skin and Hair
DHT has a complicated relationship with hair. On the face and body, it stimulates growth. On the scalp, it can do the opposite. In people genetically prone to pattern hair loss, DHT binds to receptors in susceptible hair follicles and triggers a process called follicular miniaturization. The active growth phase of each hair cycle shortens, follicles gradually shrink, and the hairs they produce become finer and shorter until some stop producing visible hair altogether. This process is the central mechanism behind androgenetic alopecia, the most common form of hair loss in both men and women.
DHT also ramps up activity in the sebaceous glands, the tiny oil-producing glands attached to hair follicles. It increases sebum production and, according to research on cultured skin cells, triggers inflammatory signaling molecules that contribute to acne. This is why hormonal acne often clusters in areas with high concentrations of androgen receptors, like the jawline and chin, and why it tends to flare during periods of hormonal change.
Prostate Growth
The prostate gland depends on DHT for both its initial development and ongoing maintenance. During normal growth, this is beneficial. In adulthood, however, DHT-driven cell proliferation can become a problem. Benign prostatic hyperplasia (BPH), the non-cancerous enlargement of the prostate that affects most men as they age, is fundamentally a DHT-dependent process. The gland keeps growing in response to DHT signaling, eventually pressing on the urethra and causing urinary symptoms like frequent urination, weak stream, or difficulty emptying the bladder.
This understanding led to an entire class of medications (5-alpha-reductase inhibitors) designed to block DHT production. These drugs can shrink the prostate, improve urinary symptoms, and reduce the risk of needing surgery for BPH.
Sexual Function and Muscle
One common concern is whether DHT is essential for sexual function and physical performance in adult men. A study published in JAMA from Boston University tested this directly. Men receiving testosterone supplementation were split into two groups: one also received a drug that blocked DHT production, while the other did not. The result was that blocking DHT conversion made no significant difference in muscle mass, muscle strength, or sexual function. Testosterone itself appears sufficient for maintaining these outcomes in adults, and DHT’s conversion from testosterone is not required for them.
This finding matters practically because millions of men take DHT-blocking medications for hair loss or prostate issues and worry about side effects in these areas. While individual responses vary, the controlled evidence suggests testosterone handles these functions without needing to become DHT first.
DHT in Women
Women produce DHT too, just in much smaller amounts. Premenopausal women average about 9 ng/dL of serum DHT, dropping to roughly 3 ng/dL after menopause. For comparison, healthy adult men typically fall in a range of about 14 to 95 ng/dL depending on the reference laboratory used. When women’s DHT levels climb above normal, the effects mirror what DHT does in men: excess facial and body hair (hirsutism), scalp hair thinning, oily skin, and acne. Elevated androgens including DHT are a hallmark of polycystic ovary syndrome (PCOS), one of the most common hormonal conditions in women of reproductive age.
Medications That Block DHT
Two widely prescribed 5-alpha-reductase inhibitors target DHT production at different intensities. Finasteride blocks only the type 2 enzyme and reduces circulating DHT by about 70%. Dutasteride blocks both type 1 and type 2 enzymes, suppressing serum DHT by roughly 94%. Both are used for BPH, and finasteride at a lower dose is the standard prescription for androgenetic hair loss in men.
Because these drugs work by cutting off DHT rather than testosterone, they target the specific processes DHT drives (prostate growth, follicle miniaturization) while largely leaving testosterone-dependent functions like muscle maintenance intact. The tradeoff is that some users report side effects related to sexual function, though large trials show these affect a small percentage of people taking them.