Mechanisms of Action
5AR
5-Alpha-Reductase
An enzyme that converts testosterone to DHT, the hormone linked to pattern hair loss.
5-alpha-reductase (5AR) is a family of enzymes (types I, II, and III) that catalyze the irreversible conversion of testosterone to dihydrotestosterone (DHT). Type II 5AR is predominantly found in hair follicles, prostate, and seminal vesicles. DHT has a 5-fold greater affinity for the androgen receptor than testosterone and is the primary driver of androgenetic alopecia (pattern hair loss). Pharmaceutical inhibitors (finasteride targets type II; dutasteride targets types I and II) and botanical alternatives (saw palmetto, pumpkin seed oil) aim to reduce DHT production.