Hair loss, thinning and cancer treatment

Hair loss or thinning is a common side effect of some cancer treatments.

It's quite common to have hair loss or thinning with some chemotherapy drugs. Hormone therapy, targeted cancer drugs and immunotherapy are more likely to cause hair thinning. But some people might have hair loss. 

Radiotherapy makes the hair fall out in the area being treated. Hair on other parts of the body is not usually affected.

Cancer drugs

Whether you lose your hair depends on:

  • the type of drug or combination of drugs you're having
  • the amount (dose)
  • your individual sensitivity to the drug
  • your drug treatment in the past

These drugs can cause:

  • mild thinning of your hair
  • partial or patchy hair loss
  • complete hair loss (alopecia)

Complete hair loss can happen gradually. Or hair may fall out fairly quickly, in clumps.

You might also have thinning or loss of eyelashes, eyebrows and other body hair. For example, pubic hair, underarm hair and chest hair in men.


Chemotherapy drugs work by killing growing cells such as cancer cells. But normal body tissues such as the hair follicles, also have lots of growing cells. This is what makes your hair fall out.

Not all chemotherapy drugs cause hair loss. Some don't cause any hair loss at all, or only slight thinning. If your hair is going to fall out, it usually begins within 1 to 3 weeks after treatment starts.

Hair usually grows back once your treatment has finished. However, in some people it may not grow back, or it might grow back patchy. This usually only happens with very high doses of particular drugs.

It might take several months for hair to grow back. It might look the same as before, or it may be thicker or thinner. Sometimes it can be a different colour or curlier.

Targeted cancer drugs and immunotherapy

There are different types of targeted cancer drugs and immunotherapy that can cause hair problems to different degrees. Some of these drugs cause slower hair growth, hair thinning and dry, brittle hair. Some might cause complete hair loss. They can develop between several weeks to 2 to 3 months after starting treatment.

Instead of hair loss, some targeted cancer drugs cause growth of hair in unexpected areas of the body. For example, excessive hair on the face in women. Or some people might develop very long, curly eyelashes.

Talk to your doctor or nurse if your treatment is causing excessive hair growth. Ask about the safest way to remove unwanted hair. For example, you (or someone else) might need to carefully trim your eyelashes every few weeks to stop them irritating your eyes.

Hormone therapy

Hormone therapies are more likely to cause hair thinning. This usually slows down or stops within the first year of starting treatment.

In some people, it may not thicken until a few weeks after finishing hormone therapy. 

Ask your doctor or specialist nurse if your drugs are likely to cause hair loss.


Radiotherapy generally causes some hair loss to the part of the body that is being treated. How much hair loss you have depends on the size of the area you have treated and the dose of the radiotherapy.

Radiotherapy to the head always causes some hair loss. Your hair will fall out where the radiotherapy beams enter your head. You can also lose some hair on the opposite side, where the radiotherapy beams pass through.

Hair usually grows back for most people. But some people might have permanent hair loss. This is more likely if you have had higher doses of radiotherapy. Ask your doctor what they think might happen in your situation.

It might take more than 6 months or more after radiotherapy for your hair to grow back. Hair regrowth may be patchy at first, and it might stay patchy for some people.

Reducing hair loss from chemotherapy

Some people want to look into ways of reducing hair loss from their treatment. There is no known way to prevent hair loss from radiotherapy, hormone therapy, targeted cancer drugs or immunotherapy. For chemotherapy, it might be possible to try scalp cooling to reduce hair loss.

Scalp cooling

Scalp cooling can sometimes reduce the amount of hair loss. 

Scalp cooling lowers the temperature of your scalp and reduces the blood flow in the scalp. This reduces the amount of drug reaching the hair follicles on your head. With less of the cancer drugs getting to the hair follicles, the hair is less likely to die off and fall out. 

There are different types of scalp cooling, these include the:

  • cold cap – a hat filled with gel that is chilled before you put it on
  • refrigerated cooling system – you wear a cap that is attached to a machine, the machine pumps liquid coolant into the cap

You can ask your doctor or nurse whether your hospital has scalp cooling and which type they use. They can explain exactly what happens.

Photograph of woman with cold cap
Photograph of man with cold cap

When not to use scalp cooling

Scalp cooling is not suitable for use in all types of cancer or situations. You won’t normally have scalp cooling if there is too high a risk that there might be cancer cells in your scalp blood vessels. This is because the cells in the scalp blood vessels might survive the treatment.

Scalp cooling is not recommended in people:

  • with blood cancers such as leukaemia and lymphoma
  • whose cancer has spread to the scalp
  • who are due to have radiotherapy to their scalp

You would not have scalp cooling with continuous chemotherapy through a pump or with chemotherapy tablets. This is because you would have to wear the cold cap for 24 hours a day. 

Possible risk

Some doctors are not happy about their patients using scalp cooling for any type of cancer. They worry about the risk of cancer cells being left in the scalp, leading to cancer spread in the skin of the scalp (scalp metastases).

In theory there is a risk, but there is not enough evidence to know this for sure. Research in this area has mainly looked at women with breast cancer.

A 2017 review of 10 different studies looked at the number of scalp metastases in women who had scalp cooling and women who did not. The number of women affected with scalp metastases in either group was small and there was no significant difference between the 2 groups. Scalp metastases are very rare in women with breast cancer.

Things to think about

Scalp cooling only blocks certain drugs and does not work for everyone. You might still have hair thinning, or lose your hair completely. You can't tell whether it will work for you until you try it.

You spend longer at hospital having your treatment if you have scalp cooling. You need to wear the cap before, during and after you have the chemotherapy drugs into your bloodstream.

The time varies depending on the drug and type of cold cap system your hospital has. For the Paxman scalp cooling system you might wear the cap:

  • before treatment or about 30 to 45 minutes depending on your hair type
  • during treatment for as long as it takes to recieve your chemotherapy drugs
  • after treatment for a minimum of 30 to 90 minutes depending on the drugs you have had

Your nurse might ask you to dampen or wet your hair before you put on the cap or cooling system. This is to improve contact between the scalp and cap and lowers the temperature of the skin on your scalp.

You also have a small amount of conditioner added to help in removing the cap after you have finished treatment.

Research suggests that scalp cooling with Afro Caribbean hair is not as successful. So your nurse might recommend you have longer periods of scalp cooling if this applies to you.

Side effects of scalp cooling

Scalp cooling can make you feel cold all over and uncomfortable. At the start, you might feel very uncomfortable for around the first 15 minutes. This should then ease. Let your nurse know if you can’t cope and want to stop the treatment. Scalp cooling can also:

  • give you a headache
  • cause pain in your forehead
  • make you feel sick
  • make you feel dizzy and light headed

Tips for helping you cope with scalp cooling:

  • take extra layers to put on
  • take or ask for a blanket
  • drink hot drinks to help you feel warmer
  • ask for some painkillers before the scalp cooling starts
Talk to your specialist nurse if you are interested in trying scalp cooling. You can discuss the possible risks with your specialist if you are worried.
Last reviewed: 
12 Jul 2019
  • Risk of dermatologic and mucosal adverse events associated with PD-1/PD-L1 inhibitors in cancer patients. A meta-analysis of randomized controlled trials.
    W Yang, S Li and Q Yang
    Medicine, 2019. Volume 98, Issue 20, Pages 1 - 13.

  • Toxic Side Effects of Targeted Therapies and Immunotherapies Affecting the Skin, Oral Mucosa, Hair, and Nails
    M Lacouture and V Sibaud
    American Journal of Clinical Dermatology, 2018. Volume 19, Supplement 1, Pages 31 - 39

  • Management of Immune-related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: American Society of Clinical Oncology Clinical Practice Guidelines
    J R Brahmer and others
    Journal of Clinical Oncology, 2018. Volume 36, Issue 17, Pages 1714 – 1768

  • Scalp Cooling Guidelines for Adult Oncology Patients. West Midlands Expert Advisory Group for Systemic Anti-Cancer Therapy (SACT)
    S Neal and S Toland
    NHS England, 2017.

  • Factors Influencing the Effectiveness of Scalp Cooling in the Prevention of Chemotherapy-Induced Alopecia
    M C Manon and others
    Oncologist. 2013. Volume 18, Issue 7. Pages 885–891

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact with details of the particular issue you are interested in if you need additional references for this information.

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