Eventually a new hair in anagen will push out the telogen hair. This gives rise to normal shedding and a typical healthy person will lose about 30-50 hairs per day with widespread variation between individuals. The ratio of anagen to telogen hairs is normally about 90 to 10, since under normal circumstances the number in catagen at any given moment is small. Apart from hairshaft breakage, hair loss usually occurs because of either too many hairs entering telogen or too few entering anagen. Hair in other areas of the body differs in several ways.
Wide variation occurs between individuals, even in normal health.
Androgenetic alopecia is not sex-linked and can affect both sexes, although not in the same way. The term 'alopecia' means hair loss and, unless qualified, does not differentiate between causes or type of loss. The two dietary factors that probably affect the health of hair most are deficiencies of iron and protein. Hair can be affected by iron deficiency when there are no clinical signs of anaemia and when haemoglobin levels are clinically normal. Always be aware of the possibility of iron deficiency in someone who has recently 'gone vegetarian'.