Women lose their hair as often as men do. They just don't lose as much.

All women lose hair when they have a sudden loss of estrogen after stopping birth control pills, after giving birth and after entering the menopause. They also lose hair after various illness, after suffering a high fever, and after losing weight rapidly. It is extremely rare that these factors cause permanent hair loss as normal hair growth usually returns to normal within nine months. Hair grows for three years, rests for three months and then starts to grow again. You cannot reverse hair loss until most hairs have gone from resting to active growing and that takes around nine months. Many other factors cause hair to fall out, such as skin diseases, toxins and lack of nutrients. Polycystic Ovary Syndrome (PCOS) is a common cause of male-pattern baldness in women.

A derivative of the male hormone, testosterone, called dihydrotestosterone, causes male pattern baldness in both men and women. A two percent solution of monoxidil, called Rogaine, increases the blood supply to these hairs and helps to slow their loss, although it helps to grow visible new hair only 20 percent of the time. Another drug, called spironolactone, can block the male hormones that cause hair loss and when applied to the scalp as a two percent solution in alcohol, it also can slow hair loss. When Rogaine solution is applied to the scalp at the same time as spironolactone, it emits a highly offensive odor, so they cannot be applied together. Rogaine can be applied in the morning and spironolactone can be applied at night without causing the odor.