Why Hair fall

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’).Both become more pronounced until they eventually meet, leaving a horseshoe-shaped ring of hair around the back of the head.

The incidence of pattern baldness varies from population to population and is based on genetic background. Environmental factors do not seem to affect this type of baldness greatly. One large scale study in Maryborough, Victoria, Australia showed the prevalence of mid-frontal baldness increases with age and affects 73.5 percent of men and 57 percent of women aged 80 and over. A rough rule of thumb is that the incidence of baldness in males corresponds roughly to chronological age. For example, according to Medem Medical Library's website, MPB affects roughly 40 million men in the United States. Approximately one in four men will have noticeable hair loss by age 30, and this figure increases to two in three men by age 60. In rare cases, MPB can begin as early as age 12.

The genetics of MPB are not yet fully understood. Most likely there are multiple genes that contribute towards MPB, the most important of which appears to be the Androgen Receptor gene, located on the X chromosome (inherited from the mother). It was previously believed that baldness was inherited from the maternal grandfather. While there is some basis for this belief, it is now known that both parents contribute to their offspring's likelihood of hair loss. Most likely, inheritance involves many genes with variable penetrance.[medical citation needed]

The trigger for this type of baldness is dihydrotestosterone, a more potent form of testosterone often referred to by its acronym DHT. DHT is an androgenic hormone, body- and facial-hair growth promoter that can adversely affect the prostate as well as the hair located on the head.The mechanism by which DHT accomplishes this is not yet fully understood. In genetically prone scalps (i.e., those experiencing male or female pattern baldness), DHT initiates a process of follicular miniaturization, in which the hair follicle begins to deteriorate. As a consequence, the hair’s growth phase (anagen) is shortened, and young, unpigmented vellus 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 so that it resembles fragile vellus hair or "peach fuzz" until, finally, the follicle goes dormant and ceases producing hair completely.