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Why do people lose their hair when going through chemotherapy?


Updated May 15, 2014

Question: Why do people lose their hair when going through chemotherapy?
My mother is going through chemotherapy and the doctor said that the chemotherapy drugs may or may not cause her to lose her hair. What determines it?
Answer: Hair loss is a common side effect of chemotherapy treatment. It generally starts to happen a few weeks after chemotherapy starts. For most people, regrowth begins not long after chemotherapy has ended. Not all people will lose their hair to chemotherapy, however.

Cancer cells divide at a high mitotic rate, meaning they divide quickly -- much more than most of the cells in our body. Chemotherapy drugs work by targeting these rapidly dividing cells. Some cells in our bodies do rapidly divide, like our hair follicle cells and the cells in the lining of our stomach and digestive tract. Chemotherapy drugs simple cannot tell the difference between these normal, rapidly dividing cells and cancer cells, so the drug attack these cells as well.

Some of the newer cancer drugs are more precise in targeting cancer cells. This is why some people do not experience chemotherapy induced hair loss. There are varying degrees of hair loss, regardless of chemotherapy drug type and regimen. Some people will only experience thinning of the hair, while others will suffer from complete hair loss. This can also be related to the dosage of chemotherapy -- lower dosages of chemotherapy sometimes equals lesser side effects, meaning little or no hair loss. Everyone responds to chemotherapy differently.


"Detailed Guide: How Is Cancer Treated." 04 AUG 2007. American Cancer Society. Accessed 16 Feb 2009.

"Chemotherapy PDQ: Treatment Overview." 27 Feb 2007. National Cancer Institute. Accessed 16 Feb 2009.

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