How long anagen lasts is determined genetically, and varies between the sexes and from one person to another. It is the length of this time that decides how long the hair will grow before it falls out. Anagen lasts between three and seven years in most people.
As people grow older the period of anagen shortens. For example, the hair of someone with a five-year anagen can grow to a length of 60 cm before it enters the shedding phase. If their anagen period drops to three years as they age, their hair will then grow only to shoulder length before it falls out or is brushed out. So when a scanty-haired elderly lady boasts that when she was a girl she could sit on her hair, she may very well be telling you the truth!
- As we have seen, a hair grows at a rate of about 1centimetre a month.
- After one year it will be 12 cm long. After five years it will be 60 cm long.
- Waist-length hair is 80-90 cm long, and will have taken about seven years to grow.
- Shoulder-length hair will have taken only about three years. Thus only people with long anagen times can expect to grow their hair down to the waist.
As people grow older the period of anagen shortens. For example, the hair of someone with a five-year anagen can grow to a length of 60 cm before it enters the shedding phase. If their anagen period drops to three years as they age, their hair will then grow only to shoulder length before it falls out or is brushed out. So when a scanty-haired elderly lady boasts that when she was a girl she could sit on her hair, she may very well be telling you the truth!