5 Alpha-Reductase Inhibitor

**Semantic type:** Chemical Viewed Functionally

**Definition:** Any substance that inhibits steroid 5-alpha-reductase, an enzyme that converts testosterone into dihydrotestosterone (DHT). Since DHT has three times greater affinity for androgen receptors than testosterone, inhibition of 5-alpha-reductase results in a strong reduction in the androgenic effects of testosterone.

**Synonyms:** - 5-alpha reductase inhibitor - Steroid 5-alpha-reductase Inhibitor