In all of the studies trying to determine whether natural supplements like saw palmetto or green tea block DHT, they never refer to Type I DHT or Type II DHT — just DHT. Why is this? Good question, huh?
Good question. Propecia (finasteride 1mg) blocks mainly DHT type II, and Avodart (dutasteride) blocks both DHT type I & II. You would think if you block ALL the DHT it would be better against androgenic alopecia. Dutasteride is three times more potent than finasteride inhibiting the type II enzyme and 100 times more potent than finasteride inhibiting the type I form of the DHT producing enzyme. There are clinical observations that suggest that dutasteride is better than finasteride, but it is not approved for hair loss by the FDA and the long term safety on human reproduction for dutasteride (reports of sterility is a complication) have been suggested in some rare patients. We have received many reports by varying doctors who switch people from finasteride to dutasteride and get a better response. The next logical question should be: If we increase the finasteride dose to 5 mg or so, will it be better to treat hair loss? I don’t know if anyone really knows that answer for sure. Some of the original studies on finasteride suggested that the 1mg dose is the most universal dose, but it may be that a high dose in those who are refractory to finasteride may help. Some doctors are using a higher dose of finasteride on long term users. It’s a prescription drug, so I’m not suggesting you should take a higher dosage. The problems for either finasteride and dutasteride is that side effects rise when increasing dosages.
To get back to your question though — it’s been proven that type II is linked to male pattern baldness, but type I hasn’t been linked yet (though it’s possibly just not been proven yet). I couldn’t tell you why the studies out there don’t provide a breakdown by type, but I have not found scientific evidence that saw palmetto or even green tea actually block DHT anyway. And even if it did block some DHT, there is nothing in the literature that shows saw palmetto or green tea being effective for treating androgenic alopecia. I don’t mean to be a pessimist, but even Propecia does not completely stop androgenic alopecia.
The real quest should be finding other (non- DHT related) mechanism for androgenic alopecia. DHT is not the only solution out there… we just haven’t discovered the other yet.