Hair loss is a common problem that many people face, regardless of gender or age. Hair loss can occur for a variety of reasons and is usually divided into a few main categories: Androgenetic alopecia (hereditary baldness): This is the most common type of hair loss that occurs in both men and women. In men, it is called male pattern baldness and usually begins with thinning hair at the front of the head and crown. In women, thinning hair occurs more widely on the scalp. Alopecia areata: An autoimmune disease in which the body’s immune system mistakenly attacks hair follicles, causing hair to fall out in small, round patches or spots on the scalp. Hormonal causes: Hormonal changes caused by pregnancy, childbirth, menopause, or thyroid problems can cause hair loss. Stress and emotional or physical shock: Severe stress, serious illness, or major surgery, plus rapid weight loss can lead to temporary hair loss called telogen effluvium. Nutritional deficiencies: Deficiencies in protein, iron, B vitamins, and other nutrients can lead to hair weakness and loss.