Dutasteride vs Finasteride - Is there a huge difference in terms of regrowth/maintenance of hair?

There are countless studies showing that Finasteride-being the older of the two 5α-reductase inhibitors-works very well at preventing hair loss both in the short term and long term. Currently, there’s limited data about Dutasteride’s long-term performance as a hair loss treatment, meaning there’s no perfect way of knowing how effective it is over the long term.

Dutasteride was Superior to finasteride in head-to-head studies regarding hair growth. However, side effects of dutasteride have not been as extensively studied. Dutasteride has a poorer side effect profile and this must be taken into consideration. A hair expert can also very the dosage of each of the medications based upon your response and develop a customized treatment program. Good luck.
Jeff Rapaport MD
Realself All-star

It’s less relevant how much they block the enzyme as to what the actual LEVELS of DHT are in the scalp. That’s what matters. Finasteride blocks serum DHT 70 % and scalp DHT 40 %. For dutasteride these numbers are 90 % and 55 %. Dutasteride gets rid of DHT better. It potentially has more side effects too. 0.5 mg dutasteride is better than 1 mg finasteride. 2.5 mg dutasteride is better than 0.5 mg dutasteride but has far more side effects.

You are a bit over on your estimates on effectiveness, rather finasteride is about 70% and Dutasteride is about 85% in the block of DHT. This does not make it superior considering that there are some more complications of dutasteride including the risk of sterility