In this article:

• Why chemo causes hair loss?
• What type of chemo causes hair loss?
• What is the timeline for hair loss?
• How to prepare for chemo-induced hair loss

Hair loss is a well-known side effect of chemotherapy and also happens to be the most dreaded. Unfortunately, over half of all patients that receive chemotherapy will experience hair loss because the medication that targets cancer cells can also target hair cells.

Chemotherapy works by interrupting the cellular division and growth of rapidly dividing cells. Cancer cells are known for dividing and multiplying quickly, which is one reason why cancer can spread so fast throughout the body. Chemotherapy drugs are effective at disrupting the division of these cells, but they often interfere with healthy, rapidly dividing cells in the body, including:

• Hair follicles
• Cell in the bone marrow that make your red blood cells, white blood cells, and platelets
• Cells lining the digestive tract

For these reasons, chemotherapy not only causes hair loss but can also make people feel extremely nauseous and lead to anemias and an increased risk for infection.

Looking specifically at hair follicles, keratinocytes are the cells that rapidly divide to help your hair grow long. In some cases, keratinocytes grow faster than cancer cells spreading through your body, so they are at an increased risk for experiencing oxidative stress and eventual cellular death.

Certain chemotherapy medications can put you at greater risk for hair loss, including:

• Antitumor antibiotics
• Topoisomerase inhibitors
• Antimicrotubule agents
• Alkylating agents
• Antimetabolites

Aside from the type of chemotherapy you receive, the dosing and length of treatment also factor into how much hair loss you may expect. Some people are also treated simultaneously with radiation, which is less likely to cause hair loss unless the treatment is targeted in areas with hair growth.

Most people start to notice hair loss after receiving their second chemotherapy infusion, but this can vary significantly from person to person. Hair loss tends to follow a slow progression at first, but it can fall out much quicker after the first 1-2 months of treatment. Complete hair loss generally occurs after the chemotherapy is nearly finished. And, you can expect hair loss not only on your scalp but also on your eyebrows, eyelashes, and body hair.

More importantly, you should know that hair does regrow and will start to do so about three months after you conclude treatment. It takes this long because the effects of the medication can still be circulating in your system, and your hair follicles also need time to start making new cells for growth.

There is no “right” way to prepare for chemo-induced hair loss. What is most important is that you do what makes you feel most comfortable. For example, some people choose to cut their hair if it is long, so the effects of hair loss are not as pronounced at first, whereas others let it fall out naturally. Some may even opt to shave their heads once they start noticing hair loss, so they do not have to experience the process of losing their hair.

If and when your hair does fall out, make sure to use sun protection when you are outside. Many people opt for a wig, whereas others may use a headscarf or hat. Choose whatever makes you feel comfortable and protected when out in the elements.

To know what your risk for hair loss will be, talk with your oncologist. They should be able to tell you what you can expect with hair loss, the specific timeline you may follow, and what you can expect in the regrowing period.