DHT Reduction

Dihydrotestosterone is produced from testosterone by 5-alpha-reductase, of which type 1 predominates in skin and sebaceous glands and type 2 in hair follicles and the prostate. DHT binds the androgen receptor with roughly five times the affinity of testosterone, which is why relatively small circulating amounts have large tissue effects. It drives beard and body hair growth, sebum production, prostate enlargement and, in genetically susceptible follicles, the miniaturisation that produces androgenetic alopecia. That dual role makes DHT reduction a trade-off rather than a pure good: DHT is essential for male genital development in utero and contributes to libido and erectile function in adults. Pharmacological suppression is highly effective — finasteride lowers scalp DHT by around 60% and halts or reverses hair loss in the majority of men — but a minority report sexual side effects, and natural inhibitors have far smaller effects.

Decide first whether pharmacological suppression is warranted, because the effect sizes are not comparable. Finasteride at 1 mg/day for hair or 5 mg for prostate, and dutasteride at 0.5 mg/day, have robust randomised evidence and should be discussed with a clinician including the sexual side effect profile. Topical finasteride achieves similar scalp DHT reduction with lower systemic exposure and is an increasingly common compromise. Among natural options, saw palmetto at 320 mg/day of liposterolic extract has small trials showing modest hair and urinary symptom improvement, pumpkin seed oil at 400 mg/day showed hair count increases in one trial, green tea EGCG and reishi inhibit 5-alpha-reductase in vitro, and topical ketoconazole shampoo has anti-androgenic activity at the scalp. Note that lowering DHT does nothing for hair loss that is not androgen driven, so telogen effluvium, iron deficiency and thyroid causes should be excluded first.

• •Ketoconazole shampoo twice weekly for its scalp anti-androgen effect
• •Maintaining a healthy body composition
• •Correcting iron and thyroid status before assuming an androgenetic cause
• •Avoiding anabolic steroids, which dramatically accelerate androgenetic hair loss
• •Reducing chronic stress, which contributes to shedding via a separate pathway