The reasons for acne formation are as follow: testosterone converted into dihydrotestosterone (DHT), and DHT combines with androgen receptors simultaneously. When hair follicle is clogged, sebaceous gland cells are stimulated to produce certain amounts of sebum. It causes the propionibacterium acnes to proliferate, which secrete lipase that goes on to decompose sebum into free fatty acid, and lead to inflammation. Isotretinoin is one of the acne therapeutic drugs which reduce acne formation by bin ding to the retinoid receptor
