There are many common causes for hair loss for men and women, but most hair loss is genetic in nature. It is important to determine the cause of your hair loss problem before you seek a solution, since different causes have different solutions. Hair restoration is possible for some kinds of hair loss, but is less likely for others.
Androgenetic Alopecia
This condition, also referred to as male pattern baldness and female pattern baldness, is responsible for over 90 percent of hair loss in both men and women. This form of hair loss is caused by a combination of aging, hormones and genetics, and thus far, there is no surefire cure or way to prevent this condition. While you can fight the process by eating a proper diet, taking vitamins and supplements essential to hair growth and using products such as Rogaine to keep the hair you currently have, there is no proven way to reliably stimulate growth of significant amounts of hair once the follicles stop producing strands of hair.
Anagen Effluvium
This form of hair loss is caused by the introduction of poisonous substances to the body, such as chemotherapy. Once the responsible substance is no longer in the body, the hair follicles begin producing hair again.
Telogen Effluvium
This form of hair loss is caused by a variety of instigators, all of which result in more and more hair follicles resting, or no longer producing strands of hair. It can be either temporary in nature or permanent. This type of hair loss can be caused by low iron count, poor nutrition, extremely rapid weight loss or stress from a physical trauma such as surgery. It can also be triggered by emotional factors such as anxiety, mental illness extreme levels of stress.
Some medications can also cause the hair follicles to stop producing hair strands. Too much Vitamin A, too much zinc (without a proper increase of copper accompanying it) and some blood pressure prescriptions may cause loss of hair.
Sometimes hormonal changes cause this type of hair loss. Menopause and pregnancy can cause changes in hair follicle productivity.