DHT, or dihydrotestosterone, is the most potent androgen (sex hormone) in the human body. It’s made when an enzyme called 5-alpha reductase converts testosterone into a stronger form. DHT plays a central role in male sexual development before birth and during puberty, but it’s also the hormone behind common conditions like pattern hair loss and prostate enlargement.
How Your Body Makes DHT
DHT isn’t produced by a single gland. Instead, it’s created locally in tissues throughout the body when the enzyme 5-alpha reductase acts on circulating testosterone. Two versions of this enzyme matter most. Type 2 is active in the prostate, genital skin, and reproductive organs. Type 1 is found in nongenital skin, the liver, and, starting at puberty, in the scalp’s oil glands and hair follicles.
This local production is important. It means DHT levels can be high in specific tissues, like the scalp or prostate, even when blood levels look normal. That’s why DHT-related problems tend to show up in particular parts of the body rather than everywhere at once.
What DHT Does During Development
DHT is essential for forming male anatomy before birth. During fetal development, it drives the formation of the penis, scrotum, and prostate. Without adequate DHT, a genetically male fetus won’t develop typical male external genitalia, a condition seen in people born with 5-alpha reductase deficiency.
At puberty, DHT picks up again. It promotes further growth of the penis and scrotum and is the primary hormone responsible for facial hair, body hair, and pubic hair growth. It also stimulates prostate growth during this stage. Testosterone gets much of the credit for male puberty, but many of the visible, external changes are actually driven by its conversion to DHT in target tissues.
Normal DHT Levels
Blood levels of DHT vary significantly between sexes and across age groups. According to Mayo Clinic Laboratories reference ranges, adult males over 19 typically fall between 112 and 955 pg/mL. For females aged 20 to 55, levels are generally 300 pg/mL or below, dropping to 128 pg/mL or below after age 55. These ranges are wide, so a single number doesn’t mean much without clinical context.
DHT and Hair Loss
Pattern hair loss, called androgenetic alopecia, is the most well-known consequence of DHT activity. In genetically susceptible hair follicles, DHT binds to androgen receptors inside the follicle cells and enters the cell nucleus, triggering a process called miniaturization. Over repeated hair growth cycles, affected follicles produce thinner, shorter, lighter hairs until they eventually stop producing visible hair altogether.
This doesn’t happen uniformly across the scalp. The follicles on the top and front of the head are far more sensitive to DHT than those on the sides and back, which is why pattern baldness follows a predictable shape. The follicles aren’t dead in most cases. They’re still there, just progressively shrinking. That’s why early treatment tends to be more effective than waiting: it’s easier to maintain a miniaturizing follicle than to revive one that has fully shut down.
Both men and women can experience DHT-driven hair thinning, though the pattern usually looks different. Men tend to see a receding hairline and thinning crown, while women more often notice diffuse thinning across the top of the scalp.
DHT and Prostate Enlargement
The prostate is one of the most DHT-sensitive tissues in the body. Under normal conditions, DHT maintains a careful balance between cell growth and cell death in prostate tissue, keeping the gland a stable size. As men age, this balance shifts. Cell growth outpaces cell death, particularly in the zone of the prostate closest to the urethra, where androgen sensitivity is highest. The result is a gradual enlargement called benign prostatic hyperplasia, or BPH.
BPH is extremely common. The growing prostate presses against the urethra and can cause difficulty urinating, a weak stream, frequent nighttime urination, and a feeling of incomplete emptying. It’s not prostate cancer, but it can significantly affect quality of life.
Medications That Lower DHT
Because DHT drives both hair loss and prostate enlargement, a class of drugs called 5-alpha reductase inhibitors was developed to block the enzyme that creates it. Two are widely used: finasteride and dutasteride.
Finasteride primarily blocks the type 2 enzyme, while dutasteride blocks both type 1 and type 2. That makes dutasteride considerably more potent. It can reduce circulating DHT levels by up to 92%. Both medications are used for BPH, and finasteride (at a lower dose) is the most commonly prescribed oral treatment for male pattern hair loss.
These drugs don’t eliminate DHT entirely. They reduce its levels enough to slow or stop the progression of hair miniaturization and prostate growth in many people. Results take time. Hair loss treatments typically need four to six months before visible changes appear, and prostate-related improvements can take a similar timeline. For BPH specifically, the 2023 American Urological Association guidelines note that medication is often the first approach, though surgery remains the right choice in certain clinical situations.
DHT in Women
Women produce DHT too, just in much smaller amounts. It plays a role in body hair growth and skin oil production. When DHT levels are abnormally high in women, the effects can include excess facial or body hair (hirsutism), acne, and thinning scalp hair. Elevated androgens including DHT are a hallmark of polycystic ovary syndrome (PCOS), one of the most common hormonal disorders in women of reproductive age.
The drop in female DHT reference ranges after age 55, from up to 300 pg/mL down to 128 pg/mL, reflects the broader decline in sex hormone production after menopause. This shift can sometimes unmask androgen-sensitive hair thinning that wasn’t noticeable when estrogen levels were higher and providing a counterbalance.