Definition of Hair Loss

Hair Loss Definition of

Each hair grows in cycles it grows, rests, and then falls out. Usually, this cycle repeats approximately yearly. At any time, about ninety percent of a person's scalp hair is growing, a phase that lasts between two and six years. Ten percent of the scalp hair is in a resting phase that lasts between two and three months. At the end of its resting stage, the hair goes through a shedding phase.

Shedding 50 to 100 hairs a day is considered normal. When a hair is shed, it is replaced by a new hair from the same follicle located just beneath the skin surface. Scalp hair grows about one-half inch a month.

Hair is made up of a form of protein, the same material that is found in fingernails and toenails. Everyone, regardless of age, should eat an adequate amount of protein to maintain normal hair production. Protein is found in meat, chicken, fish, eggs, some cheese, dried beans, tofu, grains, and nuts.

Abnormal hair loss can be due to many different causes, but about 50 percent of the population experience normal hair loss by the time they reach 50. People who notice their hair shedding in large amounts after combing or brushing, or whose hair becomes thinner or falls out should consult a dermatologist.