What causes excessive hair growth?

Dr. Michael Roizen, MD
Internal Medicine

Humans have a love-hate relationship with hair. Everyone loves long lashes or a lush head of hair, but no one wants a unibrow. Excess hair is actually a medical condition called hirsutism, and it primarily affects women. It can cause unwanted hair growth in places typically reserved for men like the lip, chin, chest, and back. Hirsutism is principally caused by too much of the hormone testosterone, and may be caused by a number of medical conditions.


Testosterone levels can become elevated by polycystic ovarian syndrome (PCOS), a hormonal disorder that affects about one in 15 women. It causes a range of reproductive problems in women of childbearing age. But hormones, like testosterone, can also be affected by tumors of the adrenal glands or ovaries. A blood test can measure levels of hormones to help pinpoint the hairy offender.


Hypertrichosis is a different hair growth problem that is not dependent on hormones. It is caused by faulty genes or problems with metabolism. People with anorexia, a serious eating disorder, and hypothyroidism, an underactive thyroid, sometimes get hypertrichosis.


If you suspect that you have pesky hairs shooting up in unwanted (and unusual) places, talk to your doctor.
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
Excessive body hair can run in families; if your mother or sisters have excessive body hair, you may be at increased risk as well. Although women's bodies naturally produce male and female hormones, if the levels of male hormones are too high, excessive body hair growth can result. Certain medical conditions, including tumors of the adrenal gland or ovaries, Cushing's Syndrome, and polycystic ovary syndrome may also cause excess body hair. And some medications cause excessive body hair as a side effect. Consult your doctor if you are concerned about excess body hair.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.