As a person completes chemotherapy, they may notice changes in their hair. One such change, known as “chemo curls,” causes hair to grow back curly after chemotherapy. 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” is a phrase that describes chemotherapy-related changes in hair texture. This can occur after hair loss, when the hair first begins to grow back.

After losing hair during chemotherapy, the hair that grows back may be curlier, finer, thinner, or a different color from usual.

Not everyone experiences this, though, and it is usually temporary.

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

All cells undergo many processes as they grow. Chemotherapy drugs damage cells when they divide to form new cells.

But as the American Cancer Society (ACS) notes, chemotherapy drugs do not distinguish between cancerous and healthy cells, so they can also affect many healthy cells, including hair follicles.

Cancer cells divide more frequently than regular cells do, which means that chemotherapy is more likely to target them. However, hair follicles also tend to grow and reproduce quickly, which may make them more sensitive to chemotherapy drugs.

A 2023 study notes that an estimated 65% of people experience significant chemotherapy-induced hair thinning or hair loss. After the chemotherapy course is complete, the drugs linger in the body, gradually decreasing over time.

The cells that chemotherapy affects take time to recover. As the hair follicles begin to function again, they may produce hair that looks different from usual.

It is not possible to predict how chemotherapy will affect the hair in every person, but factors that may play a role include:

  • the type, strength, and duration of the treatment
  • genetics
  • hormones
  • hair type and condition before treatment
  • any skin or scalp conditions that may affect the hair
  • nutrition and tobacco use

According to the ACS, chemotherapy-related hair changes are “almost always temporary”.

As the body recovers and the hair growth cycle resumes, chemo curls often shed, and in their place, a person’s usual hair will grow. This process can take a few months, or sometimes longer, depending on the individual.

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

In rare cases, hair loss may be permanent. This is more likely to occur with certain chemotherapy regimens, such as those that use:

  • high dose docetaxel (Taxotere, Doxil)
  • a combination of taxanes and anthracyclines

Around one-third of people who survive breast cancer and one-third of children who survive cancer have long-term hair loss. However, there are treatments available.

Doctors may recommend using products such as Rogaine, which contain minoxidil, to help stimulate hair growth during recovery. This will not necessarily prevent chemo curls, but it may speed up the hair growth cycle.

Minoxidil comes in topical and oral formulations. Most studies investigating this drug as an option for chemotherapy-related hair loss have used the topical formulas. They involve using a foam or gel on the scalp every day.

However, it is essential not to use minoxidil during chemotherapy, as this could make hair loss worse by dilating blood vessels. This allows more of the chemotherapy drug to reach the follicle, potentially damaging it.

Caring for hair after chemotherapy can require some changes to a person’s usual approach, especially if they are not used to caring for curly hair or if their hair has become more brittle.

In general, it is best to:

  • wash the hair less frequently, wherever possible
  • avoid high heat or harsh chemicals
  • avoid rough towel-drying or tight hair bands
  • use gentle styling techniques, ideally air drying
  • brush and touch the hair less often, as this disrupts the curl pattern

It may help to use:

  • a gentle, fragrance-free shampoo and conditioner
  • a detangling product after washing the hair
  • a wide-toothed comb or detangling brush while the hair is still wet, to reduce breakage
  • air drying methods, or the diffuser attachment on a hairdryer, using the lowest possible heat setting

The United Kingdom cancer charity Macmillan states that using chemical products to color or perm hair may be harsh on the hair and scalp after treatment.

Make sure the scalp is less sensitive, the hair is in good condition, and always conduct a patch test before using these products.

Chemo curls are a common part of recovery from chemotherapy. Chemotherapy drugs can linger in the body after treatment, affecting many cells, including hair follicles. This can result in changes to hair texture and color.

Usually, these changes are temporary. In the meantime, gentle care and styling can make managing the hair more straightforward. There may also be treatments a doctor can offer to encourage faster hair regrowth.

Speak with a doctor about ways of managing hair changes after chemotherapy. Hair stylists with experience supporting people who have undergone cancer treatment may also be able to offer styling advice.