Lack of vitamins, inadequate nutrition
The most important cause of hair loss is inadequate nutrition. Persons lacking in vitamin B6 lose their hair and those deficient in folic acid often become completely bald. But the hair grows normally after the liberal intake of these vitamins.
Stress, Prolonged Illness, unclean conditions
Other important cause of hair loss are stress such as worry, anxiety, and sudden shock, general debility caused by severe or long standing illnesses like typhoid, syphilis, chronic cold, influenza, and anaemia; an unclean condition of the scalp which weakens the hair roots by blocking the pores with the collected dirt; and heredity.