More than 95% of hair loss in men is male pattern baldness (MPB). MPB is characterized by hair receding from the lateral sides of the forehead (known as a "receding hairline") and/or a thinning crown (balding to the area known as the ‘vertex’)
It is mainly genetically determined and is due to male sex hormone DHT (androgenetic alopecia)
DHT initiates a process of follicular miniaturization, in which the hair’s growth phase (anagen) is shortened, and young, unpigmentedvellus hair is prevented from growing and maturing into the deeply rooted and pigmented terminal hair that makes up 90 percent of the hair on the head In time. Hair becomes thinner, and its overall volume is reduced , finally, the follicle goes dormant and ceases producing hair completely.
Additional factors may be stress , dietary deficiency, dandruff and side effect of medicines Treatment depends on the stage of hair loss, either by medicines or surgical intervention.