Bald Is Beautiful: The Role of DHT

Male pattern baldness (androgenetic alopecia) affects roughly half of all men by the age of 50. It is the most common form of hair loss by a significant margin, and the mechanism is well understood.

DHT (dihydrotestosterone) is converted from Testosterone by an enzyme called 5-alpha reductase. In men who are genetically susceptible, DHT binds to androgen receptors in scalp hair follicles, triggering a process called follicular miniaturisation. Over time, the affected follicles produce thinner, shorter, lighter hairs until they stop producing visible hair altogether.

The critical point is that DHT does not cause baldness on its own. Genetics determine sensitivity. Two men with identical DHT levels can have completely different hairlines because their follicle receptors respond differently. This is why some men with very high testosterone and DHT keep a full head of hair, while others with modest levels lose theirs early.

Baldness is not simply a matter of how much DHT you have. It depends largely on how sensitive your follicles are, and that distinction matters when it comes to treatment decisions.

The options for managing hair loss fall into a few categories, each with trade-offs worth understanding.

Minoxidil (Regaine) is a topical treatment thought to work by improving blood flow to the scalp and extending the growth phase of hair follicles. It does not affect DHT levels. It works for many men, has minimal systemic side effects, and is available over the counter. The downside is that it requires daily application indefinitely, and results vary.

Low-level laser therapy and microneedling have emerging evidence for stimulating follicle activity, though results are generally modest compared to pharmaceutical options.

Hair transplant surgery is the most permanent solution, relocating DHT-resistant follicles from the back of the scalp to affected areas. It is effective but costly, and only works if there is sufficient donor hair.

Then come finasteride and dutasteride, the 5-alpha reductase inhibitors that reduce DHT production systemically. In the UK, finasteride is licensed for male pattern hair loss and is effective for many men, while dutasteride is licensed for prostate enlargement rather than hair loss. But the full story is more complicated, and it deserves its own section.

Most men only think about DHT when they are worried about hair loss.

DHT levels, tested alongside Testosterone, SHBG, and Free Testosterone, provide a window into androgen metabolism that has implications far beyond the scalp. Abnormally low DHT can reflect low testosterone, medicines that block 5-alpha reductase such as finasteride or dutasteride, or, rarely, an inherited condition called 5-alpha reductase deficiency.

Abnormally high DHT relative to testosterone can suggest enhanced 5-alpha reductase activity, which has been associated with prostate enlargement (Benign Prostatic Hyperplasia). The ratio between DHT and testosterone can give some insight into how your body is processing androgens, but a DHT result cannot diagnose prostate problems on its own, so speak to your GP if you have urinary symptoms.

In short, DHT is a clinical marker with relevance beyond hair, although it is not a routine test for most men. Including it in a hormone panel can add context to testosterone results.

The narrative around DHT has become largely negative, driven mainly by its link with hair loss. But DHT is not a waste product. It is the most potent androgen in the male body, and it serves critical biological functions.

DHT is thought to contribute to libido and sexual function, although testosterone is the main driver of male sexual desire and the exact role of DHT is still being researched. Reduced libido and erection problems are recognised side effects of medicines that lower DHT.

DHT acts in the brain too. The enzyme that makes it, 5-alpha reductase, is also needed to make neurosteroids such as allopregnanolone. These act on GABA receptors and are thought to be involved in mood and stress responses, which is one reason researchers are studying how medicines that block this enzyme affect mood.

DHT may also play a part in muscle, bone and body fat, although its exact role in these tissues is still being studied.

Finasteride works by blocking 5-alpha reductase, reducing DHT levels by approximately 70%. For hair retention, it is effective. Many men see genuine improvement in hair density within 6-12 months.

Like any medicine, it can also cause side effects, although not everyone gets them.

Sexual side effects (reduced libido, erectile dysfunction, difficulty reaching orgasm) are reported in clinical trials at rates of 2-5%, and some real-world studies suggest they may be more common, although this evidence is mixed. The MHRA, the UK medicines regulator, warns that these side effects may persist after treatment is stopped, and some men report them lasting months or years. Symptoms that continue after stopping are sometimes called Post-Finasteride Syndrome (PFS), and their causes are still being studied.

One theory involves neurosteroids. The enzyme finasteride blocks is also needed to make allopregnanolone, a neurosteroid thought to be involved in mood and sleep, and researchers are investigating whether changes in brain chemistry could explain why symptoms persist in some men. This has not been proven.

The MHRA also warns that finasteride is associated with depression and suicidal thoughts, and some men report anxiety, brain fog, insomnia and emotional numbness. In the UK, finasteride packs now include a patient card highlighting these risks, and prescribers are asked to explain them when prescribing. If you take finasteride and notice low mood or suicidal thoughts, get medical advice straight away; the patient leaflet explains what to do. Any sexual side effects are worth discussing with your prescriber or GP.

If you choose to use finasteride, testing DHT, Testosterone, SHBG, and Free Testosterone can show how your hormone levels have changed, but blood tests are not routinely required and cannot predict or rule out side effects. Whether the benefits outweigh the possible risks is a personal decision, best made with a GP, prescriber or pharmacist who knows your medical history.