DHT (dihydrotestosterone) is a hormone your body makes from testosterone, and it is the main driver of male and female pattern baldness. In people with an inherited sensitivity, DHT binds to receptors in scalp follicles and slowly shrinks them until the hair they grow is too thin and short to cover the scalp. It does not cause hair loss in everyone. Your genes decide whether your follicles react to it.
The short answer
DHT is a potent androgen (male-type hormone) that both men and women produce. An enzyme called 5-alpha-reductase converts a small share of your testosterone into DHT, which binds to hair follicle receptors about five times more strongly than testosterone does. In follicles you inherited to be DHT-sensitive, that binding shortens the growth phase of each hair cycle. With every cycle the follicle gets a little smaller, and the hair it produces gets finer, shorter, and lighter. This slow shrinking is called miniaturization, and it is the core process behind androgenetic alopecia. The follicles at the back and sides of the scalp are usually DHT-resistant, which is why those areas keep their hair and why they serve as the donor zone in a hair transplant. Blocking DHT with medication can slow or partly reverse the process, but it works only while you keep taking it.
How does your body make DHT?
Your body makes DHT from testosterone using the enzyme 5-alpha-reductase. Two forms of that enzyme exist, type 1 and type 2, and type 2 is the one concentrated in scalp hair follicles and the prostate. When testosterone reaches these tissues, 5-alpha-reductase strips off part of the molecule and turns it into DHT. Only a small percentage of your total testosterone becomes DHT, but DHT is far more powerful at the receptor level, so a little goes a long way. This is also why total testosterone levels and pattern baldness track poorly together. What matters is how much DHT reaches the follicle and how sensitive that follicle is, not how much testosterone is in your blood. According to StatPearls from the National Institutes of Health, this DHT and receptor interaction is the central mechanism of androgenetic alopecia.
Why does DHT shrink some follicles and not others?
DHT shrinks only the follicles you inherited to be sensitive to it, which is why baldness follows a pattern. Follicles across the front, temples, and crown tend to carry more androgen receptors and more 5-alpha-reductase activity, so they respond strongly to DHT. Follicles at the back and sides of the scalp are genetically programmed to resist it, so they keep growing normally for life. This built-in map is why hair loss forms the familiar receding hairline and thinning crown rather than falling out evenly. It is also the reason transplants work. A surgeon moves DHT-resistant follicles from the donor zone into thinning areas, and those follicles keep their resistance in their new location. You can see how the pattern advances stage by stage on the Norwood scale of hair loss, or estimate your own stage with the Norwood scale quiz.
What is follicle miniaturization?
Miniaturization is the gradual shrinking of a hair follicle over repeated growth cycles until it can no longer produce visible hair. Each scalp hair grows for a set anagen (growth) phase, rests, sheds, and regrows. DHT shortens the anagen phase in sensitive follicles, so each new hair spends less time growing and comes in thinner and shorter than the last. Over years the thick terminal hairs turn into fine, pale vellus hairs, and eventually the follicle may stop producing a hair you can see at all. This is why early pattern loss shows up as thinning and loss of density rather than bald patches. The hairs are still there, just progressively smaller. Understanding the hair growth cycle makes it clearer why treatment takes months to show results, since you are waiting for new, healthier cycles to grow out.
Can you lower DHT or block its effect?
Yes, and the two proven prescription treatments work in different ways. Finasteride blocks the type 2 form of 5-alpha-reductase, which lowers scalp and blood DHT and slows or partly reverses miniaturization in many users. Minoxidil does not touch DHT at all. It extends the growth phase and improves blood flow to the follicle, so it is often paired with finasteride. Both are approved by the U.S. Food and Drug Administration for hair loss, and the American Academy of Dermatology lists them as first-line options. The catch is that both work only while you use them. Stop, and DHT resumes its effect and the gains fade over the following months. You can compare how these drugs work on our hair loss medications guide, and read the evidence on whether finasteride really stops hair loss. Some people also ask about supplements marketed as natural blockers, which have weaker and slower evidence.
Risks and honest expectations
DHT-blocking medication can cause side effects, so the decision is personal and worth discussing with a doctor. Finasteride is associated with sexual side effects in a small percentage of users, and it is not for women who are or may become pregnant. Lowering DHT slows loss but does not regrow a fully bald scalp, because once a follicle is gone, no drug brings it back. That is the honest limit. Medication protects the hair you still have and can thicken miniaturized hairs, while a transplant is what restores coverage to areas that are already bare. Most people who keep their hair long term use a combination: medication to defend native hair against DHT, and surgery when there is enough loss to warrant it. For a full picture of causes beyond hormones, see our guide to hair loss causes in men.
Frequently asked questions
Does high testosterone cause baldness? Not directly. Pattern baldness depends on DHT and on whether your follicles inherited sensitivity to it, not on your total testosterone level. Men with average or even low testosterone can go bald, and men with high testosterone can keep full hair. What matters is the DHT reaching sensitive follicles.
Can you feel or test your DHT levels? A blood test can measure DHT, but the number alone does not predict baldness, because scalp sensitivity varies from person to person. Dermatologists usually diagnose pattern hair loss from the pattern itself and your history rather than from a hormone panel. A specialist can advise whether testing adds anything in your case.
Do natural DHT blockers work as well as finasteride? No. Supplements such as saw palmetto show milder and slower effects in smaller studies, and none match finasteride, which blocks the enzyme by roughly 70 percent. They may appeal to people who want to avoid a prescription, but expectations should stay modest. Talk to a clinician before combining any supplement with medication.
About this guide. The Hair Transplants DFW editorial team researches every guide using peer-reviewed studies, published clinical data, and current Dallas-Fort Worth market pricing. We are an independent resource, not a clinic, and we have no financial relationship with any specific provider. This content is educational and is not medical advice; consult a board-certified hair restoration surgeon or dermatologist about your situation. Read our editorial standards or request a free consultation.