Dihydrotestosterone is the 5α-reduced metabolite of testosterone generated by the enzymes SRD5A1/2. It binds the androgen receptor with ~3 × higher affinity than testosterone, shortening the anagen phase and miniaturising susceptible follicles in androgenetic alopecia (AGA). Systemically, DHT influences prostate growth and sexual differentiation, making it a central target for 5-α-reductase inhibitors used in both dermatology and urology.
