Dihydrotestosterone, or DHT, is a powerful sex hormone made from testosterone. Your body converts roughly 5% to 10% of circulating testosterone into DHT using an enzyme called 5-alpha reductase. While testosterone gets most of the attention, DHT is actually the stronger of the two. It binds to the same hormone receptors as testosterone but dissociates from them more slowly, which gives it greater biological potency. That slow release is what makes DHT the dominant force behind several male traits, from facial hair to prostate growth, and also behind some unwanted effects like hair loss.
How Your Body Makes DHT
DHT doesn’t come from a gland directly. Instead, it’s produced when the enzyme 5-alpha reductase converts testosterone in tissues throughout the body, including the skin, hair follicles, liver, and prostate. There are two main types of this enzyme. Type 1 is found primarily in the skin and liver, while type 2 is concentrated in the prostate, hair follicles, and genital tissue. Both convert testosterone into DHT, but they do so in different tissues and respond differently to medications.
In healthy adult men, normal blood levels of DHT typically fall somewhere between 11 and 95 ng/dL, though ranges vary depending on the lab and the man’s age. Levels tend to remain relatively stable through middle age and may shift modestly in older men. Women also produce DHT, but in much smaller amounts.
What DHT Does During Development
DHT plays an irreplaceable role before birth. During fetal development, the type 2 enzyme converts circulating testosterone into DHT, which drives the formation of the penis, scrotum, and prostate. Without adequate DHT at this stage, male external genitalia do not develop normally. DHT also helps stimulate the tissue growth needed for the testes to descend into the scrotum.
At puberty, DHT kicks in again. It promotes further growth of the penis and scrotum and is the primary hormone responsible for the appearance of facial hair, body hair, and pubic hair. Testosterone handles many aspects of puberty (deepening of the voice, muscle growth, bone density), but the features most people associate with physical masculinity, particularly body and facial hair, are largely driven by DHT.
DHT and Hair Loss
The same hormone that puts hair on your face can take it off your head. Male pattern hair loss, known clinically as androgenetic alopecia, is the most visible effect of DHT in adulthood. DHT binds to androgen receptors in genetically susceptible hair follicles on the scalp and activates genes that cause those follicles to shrink, a process called follicular miniaturization.
Here’s what that looks like over time: DHT speeds up the growth phase of the hair cycle, pushing the follicle through its stages faster than normal. But each shortened cycle produces a slightly thinner, shorter hair. Over many cycles, the follicle miniaturizes until it produces only fine, nearly invisible hairs, or stops producing visible hair entirely. This is why hair loss is gradual. It’s not that follicles die suddenly; they slowly shrink over years. Importantly, not all scalp follicles are equally sensitive. The follicles at the temples and crown carry more androgen receptors, which is why hair loss follows a predictable pattern in most men.
DHT and the Prostate
DHT is the primary androgen inside the prostate gland. As men age, the combination of ongoing DHT activity and the aging process contributes to benign prostatic hyperplasia (BPH), or non-cancerous prostate enlargement. Interestingly, DHT levels inside the prostate don’t actually rise in men with BPH. They stay at normal levels even as blood testosterone declines with age. The prostate essentially maintains its own steady supply of DHT regardless of what’s happening in the bloodstream, and over decades, that sustained exposure promotes tissue growth.
BPH can cause urinary symptoms like a weak stream, frequent urination, and difficulty fully emptying the bladder. It’s extremely common: most men will experience some degree of prostate enlargement if they live long enough.
DHT’s Effects in Women
Women produce DHT too, and when androgen levels rise above normal, the effects are noticeable. Excess androgens are one of the most common hormonal disorders in women of reproductive age, affecting the skin, hair, and menstrual cycle. The classic signs include hirsutism (excess hair growth on the face, chest, or back), acne, and thinning hair on the scalp, sometimes alongside irregular periods.
In a study of 228 women investigated for high androgen levels, about 28% were diagnosed with polycystic ovary syndrome (PCOS), which combines excess androgens with irregular menstruation. Another 44% had elevated androgens but normal periods. Women with hirsutism tended to have the highest androgen levels and the lowest levels of a protein that binds testosterone and keeps it inactive. The pattern reinforces that DHT and related androgens, even in modest excess, can produce visible changes in women’s skin and hair.
DHT and Skin Oil Production
It’s widely assumed that DHT drives oily skin and acne by stimulating the sebaceous (oil) glands, but the evidence is surprisingly weak. In men born with a genetic deficiency of the type 2 enzyme, who produce very little DHT, oil production is completely normal, identical to men with typical DHT levels. Similarly, men treated with medications that lower DHT show no reduction in skin oil output.
This suggests that either the sebaceous glands need only a tiny amount of DHT to function normally, or that testosterone itself (rather than DHT specifically) maintains oil production, or that a different enzyme type in the skin handles the conversion independently. Whatever the mechanism, blocking DHT doesn’t reliably reduce oily skin.
Medications That Lower DHT
Two main medications reduce DHT levels by blocking the 5-alpha reductase enzyme. Finasteride targets the type 2 enzyme and lowers blood DHT by about 70%. Dutasteride blocks both type 1 and type 2 enzymes, suppressing blood DHT by roughly 95% at standard doses, with less variability between patients. Inside the prostate, finasteride can reduce DHT by 85% to 90%.
These drugs are prescribed for two main conditions: hair loss and prostate enlargement. For BPH, they work best in men with larger prostates, where the reduction in DHT leads to measurable shrinkage of the gland and improvement in urinary symptoms over several months. For hair loss, lowering DHT slows or stops follicular miniaturization, and some men see partial regrowth. The tradeoff is that reducing a potent androgen can cause side effects in a subset of users, most commonly reduced libido and sexual function, which typically reverse after stopping the medication.
Because DHT is essential for male genital development before birth, these medications are never used during pregnancy. In adults, though, the developmental work is long finished, and lowering DHT primarily affects the prostate and hair follicles rather than reproductive anatomy.