The most common causes of hair loss in both male and female are hormone-related. Hormonal hair loss or “androgenetic alopecia,” is the most common cause of adult hair loss. Male hormones (androgens) are believed to underline the mechanism of hair loss. Two key androgens involved in hair loss are Testosterone and Dihydrotestosterone (DHT).
Testosterone is converted by the enzyme 5-alpha reductase to its active form DHT, which then binds androgen receptor found on and inside of various cells including hair follicles. Androgen receptor activation causes miniaturisation and eventual loss of hair as the hair follicles become smaller and thinner. Additionally, the growing phase (anaphase) of the hair cycle is also reduced, further contributing to hair loss.