Androgenetic Alopecia, also known as male pattern hair loss, is the most common form of hair loss accounting for 95% of hair loss in men. Female pattern hair loss is the preferred term for Androgenetic Alopecia in females, and affects as many as 12% of females aged from 20 to 29 years, and over 50% for women over the age of 80.

As the name suggests, Androgenetic Alopecia involves the action of androgens (male sex hormones), specifically DHT (dihydrotestosterone). Individuals with pattern hair loss have an increased sensitivity to DHT. DHT binds onto susceptible hair follicles, causing them to shrink. Over time this impacts the hair growth cycle where hair starts to thin, shorten and eventually stop growing.