For men, most hair loss is the result of male pattern baldness. Also known as androgenetic alopecia or hereditary hair loss, it affects around a third of all men. The triggers are hormonal activity and hereditary factors that cause the hair follicles to shrink, eventually leading to a shortening of the hair's growth cycle. Hair becomes thinner, then stops growing. Hair loss treatments work by reinvigorating shrunken hair follicles, increasing and prolonging hair growth and helping hair to grow longer and thicker over time. Some health conditions may cause hair loss, talk to your pharmacist if you are concerned.