Hair loss during treatment

Some cancer treatments may cause your hair to fall out or to change. Find out how chemotherapy, radiotherapy and other treatments affects hair growth.

About hair loss from treatment

Some cancer treatments may make your hair fall out completely. This may be from your head and other parts of your body. This is usually temporary. Other treatments can cause permanent hair loss in specific areas of your body. Sometimes you may not lose all your hair, but your hair can become thinner or more likely to break (brittle).

There are practical steps you can take to reduce hair loss during treatment, including scalp cooling.


Chemotherapy affects the normal hair growth cycle and causes hair loss. This is called chemotherapy-induced alopecia (CIA). Hair cells quickly recover. This means that if you lose your hair due to chemotherapy, it will almost always grow back when your treatment is over.

Many people assume that they will lose their hair if they have chemotherapy. This is not always true. If you don't lose your hair, this does not mean that the chemotherapy is not working.

Hair loss can vary from mild shedding that is hardly noticeable, to complete hair loss. The amount of hair that falls out depends on:

New chemotherapy treatments are being tested all the time. So it is not always possible to tell whether someone will lose their hair. For some people, a process called scalp cooling can reduce or prevent hair loss.

Some chemotherapy drugs make other body hair fall out. This can include eyebrows, eyelashes, nose hair, beards, moustaches, chest hair, and leg, arm, underarm and pubic hair.

This is almost always temporary. We have some practical tips to help you cope with this hair loss.

During chemotherapy

If your hair falls out from chemotherapy, it usually starts 2 to 3 weeks after your first session. Sometimes it can start within a few days, but this is rare. The first thing you may notice is hair on your pillow in the morning. You may also see more hair coming out when you brush, comb or wash it.

Some people only lose some of their hair. The remaining hair will look thinner. For other people, hair may keep falling out over several weeks, leading to total hair loss. Sometimes the hair comes out very quickly over one or two days, which can be very upsetting. You may find that your scalp feels tender. We have some tips on looking after your skin.

Your hair loss may continue throughout your treatment and for a few weeks afterwards. Sometimes your hair may start to grow back between treatments and then fall out again.

Some people do not lose their hair, but their hair becomes dry and weak and breaks easily. If this happens to your hair, be careful with your usual hair care routine to help reduce damage.

Will my hair grow back after chemotherapy?

Hair loss from chemotherapy is almost always temporary, so your hair should start to grow back. However, very rarely hair loss can be permanent. When your hair grows back, the new hair can be different to what it was like before treatment. It may:

  • be curlier, straighter, finer, fluffier or a different colour
  • grow back unevenly at different speeds.

Facial hair, such as beards and moustaches, may also grow back patchy or a different colour. It may take a while for facial hair to return to what it was like before treatment.

You will probably have a full head of hair 3 to 6 months after treatment ends. After around 12 months, you should have a good idea of how thick your hair will be.

Very rarely, after high doses of chemotherapy, not all hair grows back. Very occasionally, some follicles will not make a new replacement hair. This can make your hair permanently thinner.


Radiotherapy will only cause hair loss in the part of the body that is being treated. Hair loss can happen where the radiation beam leaves the body (for example, on the back of the neck), as well as where it enters the body. Ask your cancer specialist or radiographer to show you exactly where your hair may fall out.

The hair loss will also depend on the strength of the dose and the number of treatments you have.

  • If you have external radiotherapy to your head, you will probably lose some hair from your scalp. This will be in the areas where the radiotherapy beam goes into and out of your scalp.
  • If you are having treatment for breast cancer, and the radiotherapy includes your armpit, the hair under your arm is likely to fall out.
  • If you have a beard and have radiotherapy to your head or neck, you may lose your beard.

Hair usually begins to fall out 2 to 3 weeks after your first session. It takes about a week for the hair in the treatment area to fall out completely.

Will my hair grow back after radiotherapy?

Hair regrowth after radiotherapy will depend on lots of things, including the:

  • type and dose of treatment
  • number of treatments given
  • area of your body affected.

Your radiographer can usually tell you before the treatment if your hair is likely to grow back.

If you have been told your hair will grow back, this can start once your skin has healed after treatment. Usually, your hair will start to grow back 3 to 6 months after finishing your treatment. But it may take longer if the treatment dose has been high. The hair that grows back may be thinner, patchy or a different colour.

Sometimes the hair loss is permanent. This can be especially upsetting if it affects the hair on your head. If you have hair loss on your head, you may want to wear a hairpiece, wig or some other type of headwear. It may also be possible to have a hair transplant.

Hormonal and targeted therapies

Some people notice that their hair becomes thinner while taking a hormonal therapy or targeted therapy. This is usually mild and the hair grows back at the end of treatment. If you have a beard, you may notice that you have less beard growth.

You may notice that the hair on your head and body is finer, curlier or more brittle. Each therapy has different possible side effects.

Any hair loss from hormonal or targeted therapies nearly always grows back once you have finished treatment. Your doctor can advise you about the type of drug you are taking.


If you are having surgery in an area of the body that has hair, such as an operation for a brain tumour, an area of the head will be shaved. This is usually a small area of hair and it will grow back after the operation.