Ingredient or product comparison
Type 1 vs Type 2 5-Alpha Reductase
Two isoforms of 5-alpha reductase exist in human tissue, and each predominates in different locations. Type 1 Hair follicles, skin, sebaceous glands Copper ions (90% in vitro), dutasteride Type 2 Prostate, liver, seminal vesicles Finasteride, dutasteride Type
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- Two isoforms of 5-alpha reductase exist in human tissue, and each predominates in different locations.
- Type 1
- Hair follicles, skin, sebaceous glands
- Copper ions (90% in vitro), dutasteride
- Type 2
- Prostate, liver, seminal vesicles
- Finasteride, dutasteride
- Type 1 is the dominant isoform in hair follicles and the scalp. Type 2 is dominant in the prostate. Finasteride (Propecia) primarily blocks type 2 5-alpha reductase, which explains why it reduces serum DHT by approximately 70% but does not fully eliminate DHT production in the scalp. Dutasteride blocks both isoforms.
- This distinction matters for GHK-Cu. The copper ions it delivers inhibit type 1 preferentially. Finasteride inhibits type 2 preferentially. The two mechanisms are complementary, not redundant.