Most individuals shed between 50 and 100 hairs each day. This hair loss does not have a negative effect on a person’s appearance because simultaneously, between 50 and 100 hairs enter the growing phase.
Emotional turmoil, medications, skin conditions, poor nutrition and illnesses can cause hair follicles to enter the telogen phase prematurely, resulting in increased shedding which presents itself as temporary diffuse thinning. Thinning of hair becomes noticeable only when at least 25% of it is lost.
Between the age of 20 to 30 years, women have an average of 615 hair follicles per square centimetre (cm) but by age 50, this number falls to 485 per sq. cm. Hence, between 20 and 50 years of age women lose 20% of their hair.
Excessive hair loss occurs due to hormonal disturbances like thyroid abnormalities, cancer treatments, other medicines, high fever, severe infection. It also occurs when the diet is inadequate in the B vitamins – especially B6, biotin, inositol and folic acid; and the minerals magnesium, sulphur and zinc.
Baldness implies partial or complete lack of hair. In humans, baldness generally means androgenic alopecia or “male pattern baldness” or its variant “female pattern baldness”.
Androgen (testosterone), which is male hormone, is the main regulator of normal human hair growth. The hair root contains androgen receptors with which the testosterone from blood binds to stimulate keratin manufacturing and hair growth. Testosterone is converted to dihydrotestosterone (DHT) by the enzyme 5-alpha reductases.
Since DHT is detrimental to hair growth the ratio of testosterone to DHT is vital for determining hair growth and hair loss. Accumulation of excess DHT in hair follicle is the main culprit for male pattern baldness since it prevents essential nutrients and oxygen from reaching the hair follicle.
Over a period of time, DHT is responsible for producing finer and finer hair through each hair cycle. In the case of female pattern baldness too the hair loss is also on account of excess DHT since male hormones are also present in women albeit in smaller amounts.