Why is my hair falling out ?

Many reasons. : Thryoid problems can cause hair loss. Nutritional deficiencies--biotin, magnesium, zinc- can also cause hair loss. Is it in one area or all over? If it is falling out in patches, you need to see a dermatologist. Finally stress--physiologic- such as an illness, surgery, pregancy , can cause hair loss about 6 months later. See your doctor. It can be a sign of another systemic illness.