Everyone loses between 40 and 120 strands a day, depending on how much hair you have, your age and your hair's growth cycle. People with fine hair tend to have more of it and therefore will lose more of it than their thicker-haired sisters and brothers. Your hair also thins as you get older, particularly after menopause for women. But unlike aging men, the thinning tends to stop after awhile.
Here are common causes of thinning and hair loss:
1. Seasonality. You'll lose the most hair in the fall -- typically November and December when hair reaches maturity in its growth cycle.
2. Anemia. I know of at least two women whose hair started falling out. Blood tests showed both women were anemic. According to dermatologist George Cotsarelis, M.D., director of the University of Pennsylvania Hair and Scalp Clinic, iron deficiency is a common cause of hair loss. The Mayo Clinic reports about 20 percent of women suffer from an iron deficiency.
3. Aging. Marc Avram, MD, a Manhattan hair transplantation specialist, told Elle Magazine, "As we get older, follicles shrink, producing skinnier, shorter strands; then the follicles start to die off. That rate and the extent of that process is a matter of genetics."
3. Pregnancy Some women experience hair loss with pregnancy or as part of post-pregnancy hormonal changes. Other women experience hair loss when going on or off (usually off) the birth control pill.
4. Illness or intense stress Sometimes hair loss occurs as a result of illness. Stress, excessive weight loss, iron deficiency and thyroid problems can also cause hair loss.
If you're really worried, ask your doctor, however, experts say you really only need to worry if your part is getting wider or you can see your scalp through your hair. For severe cases, you might consult a "trichologist," a physician who specializes in hair loss.
Extra tip: If you're a woman you won't experience male-pattern baldness. Women's hair tends to thin all over. The only FDA-approved hair loss treatment is minoxidil. Minoxidil works in 60-70 percent of cases by improving the follicle's ability to produce hair.