DHT blood test and hair loss: what to know

Dihydrotestosterone, or DHT, is a hormone made from testosterone. It can affect hair follicles in people who are genetically sensitive to it, especially in pattern hair loss. A blood result does not by itself confirm the cause of shedding, because hormone activity at the follicle may not match the amount measured in blood.

A clinician may ask when the shedding began, whether it is diffuse or patchy, and whether relatives have pattern hair loss. They may also consider thyroid disease, low iron stores, nutritional problems, medicines, recent illness, or inflammatory scalp conditions. Hair loss can occur with conditions such as anaemia, coeliac disease, Crohn's disease, or chronic kidney disease, so the wider picture matters.

Arrange an assessment if shedding is persistent, sudden, patchy, or accompanied by scalp pain, scaling, or redness. Bring a list of medicines and supplements, and note recent illness, major stress, weight change, or changes in diet. Do not start hormone treatments or high-dose supplements based on a single result. A clinician may choose blood tests such as a blood count, iron-related tests, thyroid testing, or hormone testing according to your symptoms and examination.

Seek prompt medical advice for rapidly spreading patchy loss, eyebrow or eyelash loss, a painful or inflamed scalp, pus, thick crusting, or hair loss with marked tiredness, weakness, fever, or unexplained weight change. Urgent assessment is also sensible if hair loss follows a new medicine or occurs with other sudden hormonal changes.

Ask whether the pattern of loss suggests a follicle-related condition, whether a DHT test would change management, and which other blood tests are appropriate. You can also ask how long to monitor shedding, what treatments fit your medical history, and whether a scalp specialist is needed.