What Causes Hair Loss in Women?

You find strands of your hair clinging to the pillow. The gap in your part grows wider. When you brush, it seems to pull out a whole web of hair. What’s happening up there?

It’s normal to lose up to 100 hairs a day. But 1 out of 3 women shed more than that. Lots of things can be responsible, including hormones, medication, stress, and even your styling habits.

Usually, your tresses will grow back once the triggering event passes.

Female Pattern Hair Loss

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You may have heard of male pattern baldness. More than 21 million women in the U.S. are born with the female version of this condition. Also called androgenetic alopecia, it’s the top cause of hair loss for both sexes.

In men, the hair tends to thin out at the temples and can make them go bald. In women, it usually starts at the top of the head or at the part. It can look like a Christmas tree with thinned-out branches. You might hear it called female pattern baldness. But women rarely lose all their hair. Instead, their hairs tend to get sparse and give their scalps a see-through look. It usually starts in midlife after 40, and sometimes earlier, and continues through your life. Can alopecia be reversed? Read more about the steps you can take.


New mothers sometimes find their hair falling out in clumps. Blame it on sinking levels of estrogen after childbirth. The hair usually regrows when the hormones even out.

Menopause is another hormonal trigger for temporary hair loss. Again, your hair will grow back, but it may not be quite as full as before.

Medical Conditions

Hair loss can be a sign of a disease. It also can happen after an illness or treatments. They include:

  • Thyroid diseases
  • Anemia (low iron in blood)
  • Ringworm, which can spread from person to person and can cause balding
  • Infections or high fever
  • Radiation and chemotherapy for cancer
  • Autoimmune disease called alopecia areata. It makes your body attack your hair and leave round, bald patches.
  • Scarring alopecia. This more often affects African-American women. Hair starts to fall out from the middle of the scalp and fans out, leaving parts of the scalp smooth and shiny.
  • Diabetes
  • Birth control pills, blood thinners, and some steroids

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Most of the time, the hair loss is temporary and it grows back.


A big upset in your life, like a death in the family, a divorce, or unemployment, can cost you a chunk of your hair. A sudden shock or an illness can lead to a condition called telogen effluvium. A large amount of your hair could fall out while you comb or wash it.

Stress also can give some people the urge to pluck hairs from their head, eyebrows, and other places. It’s called trichotillomania, and it’s a way to ease tension, frustration, and other uncomfortable feelings.

Diet and Nutrition

If you lose a lot of weight, more than 15 pounds, you might also lose some of your hair. Other reasons include:

  • Too little iron, protein, and other nutrients
  • Too much vitamin A (usually with supplements)
  • Too little vitamin D (can be corrected by taking supplements). Learn more about the connection between vitamin D and alopecia.
  • Anorexia (severely restricting yourself from food) and bulimia (throwing up on purpose after eating)

Hair Care

If you wear your hair pulled back in a ponytail or cornrows for a long time, it can be hard on your hair. Other styling habits that can lead to problems include:

  • High heat from a blow dryer or flat iron
  • Harsh chemicals from bleach, perms, or other products
  • Tightly pulled hair from clips, bands, or pins
  • Over-shampooing or brushing and combing too much, especially when your tresses are wet


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Your doctor can zero in on what’s behind your hair loss with different tests. They’ll probably start with a physical exam and ask about your family history and medical history.

Blood tests. These look for conditions like low iron and thyroid problems.

Hair shaft exam. Your doctor will use a light microscope to check your hair shaft for any disorders.

Pull test. They’ll gently pull a hank of your hair. It gives a rough idea of how much of your strands are being lost.

Scalp exam. Your doctor will check for any infections or swelling and to see where your hair’s falling out. This can help you find out if you have female pattern hair loss.

Biopsy. Your doctor gently scrapes skin samples from your scalp and sends them to a lab for testing. This can give your doctor a more detailed look at your scalp and hair roots.

Read more on: skin problems and treatments, hair loss