MedicalTerminology DB
General Medical Terms Hormones, Diabetes & Metabolism

5-alpha reductase inhibitor

Meaning of 5-alpha reductase inhibitor: A substance that blocks an enzyme needed by the body to make dihydrotestosterone (a male sex hormone made from testosterone).

Definition of 5-alpha reductase inhibitor

A substance that blocks an enzyme needed by the body to make dihydrotestosterone (a male sex hormone made from testosterone). Dihydrotestosterone can cause the prostate to grow. 5-alpha reductase inhibitors are used to shrink an enlarged prostate gland and to improve the flow of urine in a condition called benign prostatic hyperplasia (BPH). A 5-alpha reductase inhibitor is a type of enzyme inhibitor.

Written and maintained by James Murray Last updated July 21, 2026 Educational reference, not medical advice. Read the limitations.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.