Chemotherapy, hair loss and hair regrowth in post-cancer recovery14 min read

As October is Breast Cancer Awareness month, we wanted to look closely at the way chemotherapy and other cancer treatments cause hair loss. We hope that with the knowledge behind the mechanics of certain drugs and treatments will help you – or someone you know who is currently going through these treatments – to maintain a positive outlook around your hair health during such challenging time. Some treatments and effects from these cancer treatments described in this article can apply to other forms cancer, other than breast cancer. Breast cancer specifically is often treated with surgical removal, which may be supplemented by chemotherapy, hormonal therapy or others to reduce the risk of cancer relapse. 

This article should not be taken as medical advice or recommendation, always consult with your doctor / GP / oncologist. 

“Hair loss is one of the most feared aspects of cancer treatment”

Until you face the risk of losing your hair, you never quite think how important your hair actually is. And if you have cancer and are about to undergo chemotherapy or another cancer treatment, the chance of hair loss is very real, as most cancer treatments, sadly, lead to hair loss or hair thinning. Both, men and women, report hair loss as one of the side effects they fear most after being diagnosed with cancer. We provide an overview of how and why hair loss occurs as a result of different treatments for cancer.

If you or a loved one is dealing with cancer, it may not necessarily be visible to other people, but a head wrapped in scarf – is a tell-tale sign of sickness. While hair loss is only a side effect, some people fear it more than other health complications. Educating yourself as what’s happening to your hair follicles can put you in an informed seat and help feel in control of your hair growth – after the treatment finishes. Talking to your cancer care team about your concerns as well as trusted people – and not discounting them as “vanity concerns” – may help you copy with hair loss better. Hair is part of our identity – so it is completely acceptable to worry about losing it.

Below are the types of cancer treatments we will be looking at in this article from the perspective of impact they have on hair growth and hair loss:

  • chemotherapy
  • hormonal therapy
  • targeted therapy
  • immunotherapy
  • radiation therapy

Chemotherapy effect on hair follicles

Chemotherapy is a type of cancer treatment which uses one or a combination of anti-cancer drugs (chemotherapeutic agents) as part of a chemotherapy regimen. This type of therapy works by damaging the cells that divide rapidly and therefore sensitive to anti-mitotic drugs (i.e. those drugs that prevent mitotisis or division – in cells). Cancer cells multiply rapidly, but so do some other healthy cells in your body – such as those in your bone marrow, digestive tract and hair follicles. As a result, myelosuppression (decreased production of blood cells), mucositis (inflammation of the lining of the digestive tract), and alopecia (hair loss) can occur during chemotherapy. The latter is called “chemotherapy induced alopecia” affects 65% of people undergoing this type of treatment.

Keratinocyte proliferation in hair follicles during chemotherapy

Let’s take a closer look at what’s happening in your hair follicle during the treatment. Keratinocyte stem cells and melanocyte stem cells are located in the bulge area of hair follicles (i.e., at the site of attachment of the arrector pili muscle) essentially “manufacturing” your hair strands. As chemotherapy drugs begin to curb multiplication of those cells – you hair falls out as a result. Because the drugs affect your follicles on such fundamental level, some people report changes in the hair structure itself after it grows out: for example previously straight hair can become curly and vice versa. 

Chemotherapy affects hair follicles through drug delivery, so you should not be treating your hair loss while you’re going through the treatment. As the only way you can aid your hair growth – is by stimulating blood flow to the scalp – but by stimulating blood to that area will lead to a quicker delivery of the drug to your roots – therefore affecting your hair growth even more. Therefore you should wait with hair regrowth treatment until after your chemotherapy is finished. It takes a few days for the drugs to completely leave your system – so allowing a week afterwards is a good rule of thumb. This way you are not going to be sending the remnants of your chemotherapy drug to your follicles by applying your scalp treatment too early. 

Scalp cooling in chemotherapy

Some experimental treatments include cold exposure of the scalp  (scalp hypothermia). During your chemotherapy infusions, a closely fitted cap that’s cooled by chilled liquid, is placed on your head to slow blood flow to your scalp. This aims to reduce blood flow to the scalp and lower the delivery of the drug to your hair follicles. 

Studies of scalp cooling caps and other forms of scalp hypothermia have found they work somewhat in the majority of people who have tried them. However, the procedure also results in a very small risk of cancer recurring in your scalp, as this area doesn’t receive the same dose of chemotherapy as the rest of your body. People undergoing scalp hypothermia report feeling uncomfortably cold and having headaches. Whether to explore this treatment of hair loss during chemotherapy – should be discussed between you and your doctor. Scalp cooling is not recommended for 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

All in all, hair loss happens because the chemotherapy affects all cells in the body, not just the cancer cells.  The lining of the mouth, stomach, and the hair follicles are especially sensitive because those cells multiply rapidly just like the cancer cells. The difference is that the normal cells, including cells in your hair follicles will repair themselves, making these side effects temporary. 

Hair regrowth after chemotherapy

Hair usually begins falling out 2-4 weeks after you start treatment. It could fall out very quickly in clumps or gradually. You’ll likely notice accumulations of loose hair on your pillow, in your hairbrush or comb, or in your sink or shower drain. Your scalp may feel tender and more sensitive. Your hair loss will continue throughout your treatment and up to a few weeks afterwards. Whether your hair thins out or you become completely bald will depend on your treatment.

When will my hair grow back?

It may take several weeks after treatment for your hair follicles to recover and begin growing again. When your hair starts to grow back, it could look slightly differently from the hair you lost. Your new hair might have a different texture or color. It might be curlier than it was before, or it could be gray until the cells that control the pigment in your hair begin functioning again. That difference is usually temporary as your body naturally recovers.

Hormone therapy and hair loss

Hormone therapy for breast cancer is a treatment for breast cancers that are sensitive to hormones, the type which “feed” off hormones. The most common forms of hormone therapy for breast cancer work by blocking hormones from attaching to receptors on cancer cells or by decreasing the body’s production of those hormones. It is only used for breast cancers that have receptors for the naturally occurring hormones estrogen or progesterone. Doctors refer to these cancers as estrogen receptor positive (ER positive) or progesterone receptor positive (PR positive). This means that these breast cancers are fueled by the natural hormones estrogen or progesterone.

Hormone therapy for breast cancer is often used after surgery to reduce the risk of cancer returning. This type of therapy may also be used to shrink a tumour before surgery, making it more likely the cancer will be removed completely.

In comparison to chemotherapy, this treatment doesn’t directly affect proliferation of cells within the hair follicles, instead – it affects the hormones that contribute to healthy hair growth – namely estrogen. Approximately 25% of the patients receiving hormone therapy experience hair loss or thinning. Lower levels of estrogens even naturally occurring in women (e.g. in case of PCOS) can lead to thinning hair and hair loss. 

Patients experiencing that type of hair loss or thinning are being treated with topical 5-alpha reductase inhibitors, supplementation of Vitamin C and omega-3 fatty acids without causing an adverse effect on breast cancer prognosis. Amongst those topical 5aR inhibitors is ketoconazole which affects testosterone synthesis. The body of evidence of its efficacy of treatment in androgenic alopecia varies. Application of alternative DHT blockers (saw palmetto, caffeine) as well as scalp blood flow stimulation through regimented scalp massage or other scalp treatment can be a few things to consider after the cancer treatment is completed.

Normal hair growth resumes after the hormone therapy ends and your body returns to its hormonal balance. You can ask for a blood check for hormone levels to understand your recovery from a more informed standpoint and to make sure you are not spinning the wheels fighting hair loss – while it is hormonal balance that needs to be addressed!

Targeted therapy

Targeted therapy is a type of cancer treatment that uses drugs or other substances to precisely identify and attack certain types of cancer cells. A targeted therapy can be used by itself or in combination with other treatments, such as traditional or standard chemotherapy, surgery, or radiation therapy. Drugs called angiogenesis inhibitors often target vascular endothelial growth factor (VEGF) proteins. 

The VEGF proteins help tumors build and keep a blood supply, but they also seem to be important to the very small blood vessels in limbs and around the body. VEGF proteins are important in keeping the blood supply to scalp, so depending on the type of cancer that you have had the treatment for by targeted therapy – once the treatment is complete, you can consult with your doctor to explore treatments that improve blood flow to scalp, as well as techniques and tools that improve blood flow to your hair follicles, such as dermarolling and scalp massages. 

For certain types of cancers – that around your head region and in your blood (e.g. leukaemia, lymphoma and myeloma) – you should postpone your hair growth treatment until after cancer has completely disappeared. In that period you may notice that your hair also starts re-growing on its own as your body recovers.

Immunotherapy and hair loss

Immunotherapy is a type of cancer treatment that helps your immune system fight cancer. The immune system helps your body fight infections and other diseases. It consists of white blood cells and organs and tissues of the lymph system. Some immunotherapy drugs, for example immune checkpoint inhibitors, “release the brakes” on the immune system in order to detect and attack cancer cells. However, this can potentially sway the immune system the other way where it starts attacking healthy tissues within the body thus creating an autoimmune response. 

While the most common autoimmune hair loss condition is alopecia areata, it is not a common effect of immunotherapy. Most commonly, if an autoimmune response is triggered by immunotherapy, joints and tissues get affected, but not hair follicles. In a small sample of patients taking a drug called nivolumab: a few cancer patients have developed alopecia areata. Hair loss usually begins a few months after they start treatment. Known as “nivolumab-induced alopecia areata”, the hair loss is considered a good sign. This type of hair loss usually means that the drug is working.

You can discuss with your doctor and oncologist what type of topical corticosteroid treatments available to treat the bald spots. Corticosteroids are commonly used to treat alopecia aerate. You can treat this hair loss with a corticosteroid that you apply to the bald spots, it also allows the hair to regrow without stopping cancer treatment.

Radiation therapy also can cause hair loss

Radiation therapy attacks quickly growing cells in your body, but unlike chemotherapy, it affects only the specific area where treatment is concentrated. For example, you are likey to lose hair on your head if you have radiation applied to that area. Radiation is energy that’s carried by waves or a stream of particles. It works by damaging the genes (DNA) in cells in the applied area. Genes control how cells grow and divide. When radiation damages the genes of cancer cells, they can’t grow and divide any more. Similar to chemotherapy, radiotherapy will affect rapidly multiplying cells, which includes hair follicles. Therefore you are likely to experience hair thinning and hair loss in the area where radiotherapy is applied.

Your hair usually begins growing back after your treatments end. But whether it grows back to its original thickness and fullness depends on your treatment. Different types of radiation and different doses will have different effects on your hair. Higher doses of radiation can cause permanent hair loss. Talk to your doctor about what dose you’ll be receiving to manage the expectations. 


Hair regrowth will take some time, depending on the treatment completion date and prognosis. You will begin seeing new hairs within 3-6 months of completion for most cancer treatments. It may also start growing back while you are still receiving the treatments. It helps to be prepared for your “new” hair to have a slightly different colour, texture, or curl. For example – first hair that grows may be gray in colour due to reduced melanocytes’ function as a result of the treatment.

Some ideas for how to handle hair loss during cancer treatment are:

  • Short hair – Cut your hair short if you are expecting hair loss during chemotherapy.  Since hair often does not fall out evenly, some find losing short hair can feel less distressing and cutting your hair short may make you feel empowered and “in control” over hair loss. You could also donate your hair to charity.
  • Wigs – If you are interested in purchasing a wig, the best time to do this is before you lose any hair. This helps the stylist create the best match. If you are under age of 24 and based in the UK – you will be able to get a free wig from natural hair from Little Princess Trust.
  • Caps and Scarves – Some people find that the easiest, and most comfortable options are caps and scarves.  These range from those you may already own to custom items made expressly for people who are undergoing chemotherapy. As you are regrowing your hair after your treatment is completed, you can also hold hair oil under your cap or scarf to nourish your scalp and your hair follicles back to life.
  • If you are based in the US, you might check with your local chapter of the American Cancer Society.  They sponsor a program called “Look Good, Feel Better.”  This program addresses ways to tie scarves and ways to make yourself look and feel better while experiencing hair loss during and after chemotherapy.

While this may sound daunting – and make you feel that nothing can be done to prevent hair loss – knowledge of the biology can help you see that your hair falls out because the treatment has reached the cells of your body. What is required of you at this point is to extend love, care and patience to yourself, your body and hair follicles and allow the time for it to recover. After completing your cancer treatment you can begin looking at scalp treatments that accelerate hair growth and get your hair looking as it used to – or better than it was before.

  • Prevention and Treatment of Chemotherapy-Induced Alopecia (Dermatology Practical & Conceptual), (1)
  • Chemotherapy and hair loss: What to expect during treatment, (2)
  • Association Between Use of a Scalp Cooling Device and Alopecia After Chemotherapy for Breast Cancer, JAMA, (3)
  • Immunotherapy to Treat Cancer (4)
  • Keratinocytes regulate the function of melanocytes, (5)
  • Management of hair loss associated with endocrine therapy in patients with breast cancer: an overview, (6)
  • Topical Application of Ketoconazole Stimulates Hair Growth in C3H/HeN Mice, (7)
  • Control of hair growth and follicle size by VEGF-mediated angiogenesis, (8)
  • Corticosteroids for alopecia areata in children, (9)

Who we are:

The Hair Fuel is an all-natural hair growth mask created by Laura Sagen, who lost a third of her hair after a terrible visit to a hairdresser while suffering from a life-long condition of PCOS associated with androgenic hair thinning. She developed the formulation rooted in the science of scalp blood flow, which has become The Hair Fuel growth mask. Since then, her company has helped thousands of people like you to start growing healthy hair.

We work closely with our lab and manufacturers to ensure the highest quality product. But a product alone is never enough – so we hold your hand throughout your own, unique hair growth journey. Our flagship product, The Hair Fuel mask coupled with tailored advice, digital tools, and online support is there to help you grow the best hair you can. It’s a big claim – but we’re unafraid to make it. Check out our starter bundles >>


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2 thoughts on “Chemotherapy, hair loss and hair regrowth in post-cancer recovery<span class="wtr-time-wrap after-title"><span class="wtr-time-number">14</span> min read</span>”

  1. Being diagnosed with cancer is one of the worst things that may happen to you, and it happened to me. Funny thing is, every other concern apart, I was highly worried about my hair. I knew it was only a matter of time before the treatment starts and my hair starts falling out. So, I wanted to gather the right information about the whole situation and started browsing online. This is how I ended up here at this blog. It is such a well-written blog and the writer focused on different kinds of cancer treatments that can have an impact on hair growth and hair loss. Thanks to the blog, I now have some ideas about how to deal with hair loss during the treatments.

    • Hi Linda – we’re sorry to hear about your diagnosis. It makes us glad that you found our article helpful for your journey <3 Do let us know if you have any questions as you're going through it. We’d be honoured to be there for you (and your hair) in the best way we can. If you do end up donating your hair to Little Princess Trust (or other charity) - we have a partnership scheme for that, so by all means let us know. Very best luck for the time ahead of you! X


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