Each individual hair survives for an average of 4 1/2 years, during which time it grows about 1/2 inch a month. Usually in its 5th year, the hair falls out and is replaced within 6 months by a new one. Genetic baldness is caused by the body's failure to produce new hairs and not by excessive hair loss.
Both men and women tend to lose hair thickness and amount as they age. Baldness is not usually caused by a disease. It is related to aging, heredity, and testosterone. Inherited or "pattern baldness" affects many more men than women. About 25% of men begin to bald by the time they are 30 years old, and about two-thirds are either bald or have a balding pattern by age 60.
Cause of this type of hair loss are:
- High fever or severe infection
- Childbirth
- Major surgery, major illness, sudden blood loss
- Severe emotional stress
- Crash diets, especially those that do not contain enough protein
- A number of medications, including retinoids, birth control pills, beta-blockers, certain antidepressants, NSAIDs (including iburpofen) and calcium channel blockers