One of the primary cause of hair loss is a high amount of the male hormone, dihydrotestosterone (DHT) within the hair follicle. DHT is produced from testosterone in the prostate, various adrenal glands, and the scalp. After a period of time, an over abundance of DHT causes the hair follicle to degrade and shortens the active phase of the hair.

Another factor that has been linked to hair loss is the amount of sebum in the scalp. Sebum contains a high amount of DHT, and clogs pores in the scalp, both of which cause the malnutrition of the hair root. The amount of sebum in balding hair is related to the amount of oil in the hair. Meanwhile most doctors agree that frequent shampooing is advised in hair loss cases with oily scalps.

The most important cause of hair loss is inadequate nutrition. Even a partial lack of almost any nutrient may cause hair to fall. But hair grows normally after a liberal intake of these vitamins. A high protein and and an iron rich diet is recommended for hair loss. An adequate intake of raw vegetables, fresh fruits, salads, green leafy vegetables should be included in the diet on a regular basis.

Another important cause of falling hair is stress, such as worry, anxiety and sudden shock. Stress leads to a severe tension in the skin of the scalp. This adversely affects the supply of essential nutrition required for the healthy growth of hair.

General debility, caused by severe or long standing illnesses like typhoid, syphilis, chronic cold, influenza and anaemia, also gives rise to hair disorders. It makes the roots of the hair weak, resulting in falling of hair. An unclean condition of the scalp can also cause loss of hair. This weakens the hair roots by blocking the pores with the collected dirt. Heredity is another predisposing factor which may cause hair to fall.