The average scalp contains 300,000 follicles from which grows one hair each. At any given time, 90 percent of your hair is growing and 10 percent is in a resting phase. Your hair grows a half inch per month, or about a foot a year. During the day, you can expect about 150 hairs to fall out. To promote hair growth, B vitamins, amino acids and biotin may help, but always check with your doctor.
Your hair grows from a follicle that is embedded just under the first layer of your scalp in the dermal layer. The follicle is bulb-like in shape and normally produces one hair shaft per follicle. Unlike the follicle, the shaft of hair is made of dead protein material. There are three stages of hair growth: the anagen, or active phase, when hair growth occurs; the catagen phase, or intermediate stage; and the telogen phase, or resting phase, when no hair growth occurs. After these cycles, the hair falls out and the cycle repeats.
Amino acids are the building blocks for protein. Your hair is made partly from keratin, a compilation of various fibrous proteins, including the amino acids cysteine and methionine. Cysteine is a non-essential amino acid, meaning your body is able to produce and store it. Methionine is an essential amino acid, meaning you must obtain it through dietary sources, such as meat, fish and and dairy products. Cysteine and methionine are necessary for the growth of your hair, forming part of the shaft. Supplementing with methionine may help with hair growth, but seek the advice of your doctor first.
Biotin is part of the B vitamin family. Although your body is able to make biotin in the intestinal tract, a lack of biotin may lead to hair loss. A 1981 paper in the journal “Pediatrics” relates the documented case of an adolescent boy who received raw eggs as a regular part of his diet. The boy presented with symptom of total hair loss and scaling skin. Once the egg whites were discontinued and biotin supplements began, the hair grew back. It was found that egg whites contain the compound avidin which binds with biotin and removes it from the body. The University of Maryland Medical Center also notes that many hair products include biotin in their formulas.
The B vitamin family consists of biotin, folic acid, niacin, pantothenic acid, riboflavin, thiamine, inositol, B6 and B12. The B-complex family of vitamins are vital in the metabolism of fats, carbohydrates and proteins, and the production of energy. B vitamins make proteins available for use in building new tissues and cells, including your hair. Some of the B vitamins play a more important role in hair health and growth, such as riboflavin, biotin, niacin and inositol.