Testosterone is converted to DHT by the enzyme 5-α reductase in several
organs including the prostate, hair follicles, skin, liver and sebaceous
glands. 5-α reductase exists in type 1 and type 2 forms. Type 2
is the predominant enzyme in prostate and hair follicles. Inhibits means the 5 alpha reductase enzyme cannot joint with testosterone to make
DHT, so DHT levels go down and stop hair loss.
5-alpha reductase Type 2 inhibitors include:
- Finasteride. Sold under the brand names Propecia, Proscar. Inhibits the type 2 isoenzyme, and is
available in two doses: 1mg dose for AGA, and 5mg for BPH.
- Dutasteride. Sold under the bran names Avodart. A dual inhibitor of both
1 and 2 isoenzymes.
