Personally, I would start off with Finasteride if I go by my own experience. I`ve been using it since 2005 and it`s worked very well. For better advice though I`d recommend speaking with your family doctor or try to arrange an in person consultation with a hair restoration doctor. Even if you have to pay for a consultation, the diagnosis and advice could prove invaluable. If you can avoid hair restoration surgery by holding onto your hair then that to me is the best option.
Finasteride and dutasteride are inhibitors of the enzyme 5-a reductase (5AR). This inhibits the conversion of testosterone to dihydrotestosterone (DHT), the androgen that primarily causes male pattern baldness.
There are 3 types of 5AR receptor isoenzymes, with type I and type II being significant in the treatment of AGA. Type I 5AR is the principle isoenzyme found in sebaceous glands, sweat glands, and the scalp, whereas type II 5AR is present in hair follicles and the prostate. The main difference between finasteride and dutasteride is that finasteride is selective for type II 5AR while dutasteride inhibits both type I and type II.
Dutasteride not only blocks both types of receptors but also does so much more effectively. This may be a result of the much longer half-life of dutasteride compared to finasteride (~4 weeks vs. 6-8 hours respectively). Dutasteride has been shown to be 3 times more potent than finasteride at inhibiting type II 5AR and more than 100 times at inhibiting type I 5AR. Furthermore, oral dutasteride decreases serum DHT concentrations by up to 90% while finasteride only reduces DHT by 70%
