As a person completes chemotherapy treatment, they may notice changes to their hair for some time. One such change, known as “chemo curls,” causes hair to regrow curly after chemotherapy treatment. This is often temporary.

Several other changes to the hair may also occur and can last for varying lengths of time depending on the person and their treatment.

In this article, we discuss chemo curls and why they occur. We also look at other hair changes during chemotherapy and hair care tips for after treatment.

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Chemo curls may occur because of how chemotherapy affects the body.

All cells go through many different processes as they grow. Chemotherapy drugs damage cells when they divide to form new cells. Cancer cells divide more frequently than regular cells do, which means that chemotherapy is more likely to target them.

But as the American Cancer Society notes, chemotherapy drugs cannot tell the difference between a cancerous cell and a healthy cell, so they can also affect many types of healthy cells in the body, including hair follicles.

Hair follicles tend to grow and reproduce quickly, which may make them more sensitive to chemotherapy drugs. Research from 2020 notes that up to 90% of a person’s hair is usually in a stage that chemotherapy may affect. This is why treatment often leads to hair loss.

After the chemotherapy course is complete, the drugs linger in the body for some time. The drugs slowly leave the body, but the cells they affect recover slowly. As this slow recovery occurs in the hair follicles, they may produce different types of hair. The hair may be different from the typical hair growth and may include chemo curls.

Doctors do not know how chemotherapy will affect any individual. Changes to the hair, such as the growth of chemo curls, can occur, but some people will not experience these changes.

Several factors contribute to why hair changes occur from chemotherapy, including:

  • genes
  • health history
  • hair type
  • how hair responds to the drugs

The chemotherapy drug, strength, and duration may also play a role.

Research from 2017 states that hair usually starts growing back about 3–6 months after chemotherapy. At first, the hair may be very fine or have other changes in texture or color.

The chemo curls stage of hair growth can vary because it takes time for the body to recover from chemotherapy. In the first post-treatment stages, hair growth may feel slow, and the hair may not grow back as a person expects.

This first regrowth process may last for months to a year or more in some individuals.

As the body focuses on producing healthy cells and recovering from chemotherapy, the hair should also regrow as it usually would.

A person should talk with a doctor about the side effects of any given drug or treatment. Doctors can help people understand what to expect from the treatment, including whether their hair may fall out and how long it can take to grow back. They may also provide specific recommendations for caring for the hair or helping it grow back after treatment.

Hair loss during chemotherapy is common. Around 65% of people who receive chemotherapy experience hair loss. This percentage also varies based on the drug.

Chemotherapy may affect the hair in multiple other ways, including:

  • making the scalp sensitive
  • causing the hair to grow back a different color
  • causing the hair to regrow with a different texture
  • causing the hair to be more sensitive and delicate to force from brushing or ingredients in hair care products

In rare cases, hair loss may be permanent.

Doctors cannot predict how any one person’s hair will react to chemotherapy. The effects may vary according to a person’s age, response to treatment, and general health.

Caring for the hair after chemotherapy treatment can require various methods and products. This may be especially true for people with chemo curls who previously had straight hair and are not used to caring for curls.

Some general tips for caring for hair and chemo curls after chemotherapy include:

  • air drying instead of blow-drying to help prevent frizz
  • detangling hair with a wide comb instead of a brush
  • trying styling products for curly hair, such as mousse, gel, and oil
  • avoiding hair products such as shampoos with sulfates or other oil-stripping ingredients
  • using a gentle shampoo and conditioner
  • avoiding hot water, as the scalp may be tender and prone to dandruff

In general, using chemical products to color or perm the hair may be harsh on the hair and scalp during treatment recovery. There is no exact timeline on when a person can start coloring or perming their hair, but it may help to wait until the scalp is less sensitive and the hair grows out past the chemo curl stage.

Doctors may recommend using products such as Rogaine that contain minoxidilto help stimulate hair growth during recovery.

Finding ways to help manage the changes and care for the hair may make the regrowth process easier.

Chemo curls are a common part of recovery from chemotherapy. Chemotherapy drugs can linger in the body after treatment, affecting many cells such as the hair follicles.

Chemo curls are generally not permanent and should reduce with time. Other changes to the color and texture of the hair should also go away as the drugs leave the body after treatment. In the meantime, gentle care and styling can make managing the hair much more straightforward.