Why Does Chemotherapy Cause Hair Loss?

Chemotherapy is one of the most widely used treatments for cancer. It works by using powerful drugs to target and destroy cells that grow and divide quickly—like cancer cells. However, chemotherapy can’t always tell the difference between cancerous and healthy cells. This means it may also affect other fast-growing cells in the body, such as those in the hair follicles. As a result, many patients experience hair loss during treatment.

This article will explain why chemotherapy causes hair loss, when it usually happens, whether it can be prevented, and what to expect as your hair grows back.

Why Does Chemotherapy Affect Hair?

One of the most well-known side effects of chemotherapy is hair loss—but many people wonder why it happens. The answer lies in the way chemotherapy works. These drugs are designed to attack cells that grow and divide quickly, because that’s what cancer cells do. However, the body has some healthy cells that also divide rapidly—and one of the fastest-growing types are the cells found in your hair follicles.

Hair follicles are constantly active, producing new hair cells every day. This high level of activity makes them especially vulnerable to the effects of chemotherapy. Since the drugs can’t tell the difference between fast-growing cancer cells and fast-growing healthy cells, they may end up damaging the hair follicles along with the cancer. When the follicles are affected, hair may become thinner, more fragile, or begin to fall out entirely. This can happen not only on the scalp, but also on the eyebrows, eyelashes, and other parts of the body. The medical term for this kind of hair loss is chemotherapy-induced alopecia.

It’s important to know that hair loss from chemotherapy is not a sign that the treatment isn’t working—in fact, it often means that the drugs are doing what they’re supposed to do. Still, it can be an emotionally difficult experience, and understanding why it happens is the first step toward coping with it.

When Does Hair Loss Usually Start?

Hair loss from chemotherapy doesn’t happen right away. For most people, it begins one to three weeks after starting treatment. At first, you might notice more strands of hair on your pillow, in your hairbrush, or coming out when you shower. Some people experience gradual thinning, while for others, the hair may fall out more suddenly or in larger clumps.

This type of hair loss doesn’t just affect the scalp. Depending on the specific chemotherapy drugs used, it can also lead to the loss of eyebrows, eyelashes, facial hair, and body hair. The extent of hair loss is different for everyone. Some people lose most of their hair, while others may only have mild thinning. A big part of this variation depends on the type of chemotherapy drug, the dose, how often it’s given, and how your individual body responds. Some chemotherapy medications are more likely to cause hair loss than others, and your doctor can usually give you an idea of what to expect based on your treatment plan.

While it can be emotionally challenging to watch your hair change or fall out, it’s helpful to remember that this side effect is temporary for most patients. Knowing when it might begin can help you prepare—whether that means cutting your hair short ahead of time, choosing a head covering, or simply giving yourself time to emotionally adjust.

Will My Hair Grow Back?

One of the most common questions people have during chemotherapy is, “Will my hair grow back?” The good news is that in most cases, the answer is yes. Hair loss caused by chemotherapy is almost always temporary, and regrowth usually begins within a few weeks to a few months after treatment ends.At first, the new hair may be very soft and fine, almost like baby hair. It might also grow back in a different texture or color than you had before—straight hair may come in curly, or gray hair might come in darker. These changes are often surprising but are usually temporary, and over time, your hair typically returns to its original texture and shade.

Seeing your hair start to grow back can be an emotional and uplifting experience. It’s more than just a cosmetic change—it’s a visible sign that your body is healing and recovering from the intense treatment it has been through. While the process takes time and patience, many people find that it brings a sense of hope and progress on their path to recovery. If you have concerns about how your hair is regrowing, or if you’re not seeing any regrowth after several months, it’s always a good idea to talk to your healthcare team. They can provide reassurance, guidance, or check for other reasons that might be affecting the process.

Can Hair Loss Be Prevented or Reduced?

While hair loss is a common side effect of chemotherapy, many people wonder if there’s anything they can do to prevent it or at least reduce its severity. Unfortunately, there is no guaranteed way to stop chemotherapy-induced hair loss completely—but there are a few strategies that may help in some cases. One of the most promising options is the use of scalp cooling caps, also known as cold caps. These are specially designed caps that are worn on the head before, during, and after a chemotherapy session. The cap cools the scalp, which reduces blood flow to the hair follicles, making it harder for the chemotherapy drugs to reach and damage them. Cooling caps have shown some success in reducing hair loss, especially with certain chemotherapy drugs. However, they don’t work for everyone, and not all cancer centers offer them. They may also not be suitable for people with certain types of cancer, so it’s important to discuss the risks and benefits with your doctor.

In addition to cooling caps, practicing gentle hair care can help minimize breakage and irritation. This includes using a mild shampoo, avoiding heat styling tools like blow dryers and straighteners, brushing the hair gently with a soft-bristle brush, and avoiding tight hairstyles that pull on the hair. Some patients choose to cut their hair shorter before treatment begins, which can make the process of hair loss feel less sudden and emotionally overwhelming.

It’s important to remember that everyone’s experience is different, and the effectiveness of these strategies can vary. Before trying any method to prevent or reduce hair loss, it’s always best to talk to your healthcare team. They can help you understand what to expect based on your specific treatment and whether any preventive options are appropriate for you.

Coping With Hair Loss: Emotional and Practical Tips

Losing hair during chemotherapy can be an emotionally difficult experience. For many people, it’s not just about appearance—it’s also a deeply personal reminder of their illness. It can affect self-esteem, confidence, and how someone sees themselves. This emotional impact is completely valid, and you’re not alone in feeling this way. There are helpful ways to cope. Some people find strength in joining support groups, either in person or online, where they can share their feelings and hear from others going through the same thing. Talking with a therapist or counselor can also provide a safe space to process the emotional changes. Even simple acts like journaling can help you express and manage your thoughts.

On a practical level, many patients choose to cut their hair short before it begins to fall out, which can make the change feel less sudden. Others explore wigs, scarves, or hats that help them feel more comfortable and confident. Talking openly with family and friends about your experience can also help ease emotional stress and build support. Most importantly, remember that your hair does not define you. Hair loss is temporary, and it says nothing about your courage, resilience, or beauty. It’s simply one visible part of your healing journey—and it doesn’t change who you are inside.

Read OncoDaily’s Special Article About Why Radiation Can Cause Hair Loss?

What to Ask Your Doctor

If you’re about to start chemotherapy, it’s completely normal to have questions—especially about side effects like hair loss. One of the most important things you can do is talk openly with your doctor or nurse about what to expect. Asking questions can help you feel more prepared and give you a greater sense of control during treatment. You might consider asking:

• Will this specific chemotherapy cause hair loss?

• When is hair loss likely to start, and how much should I expect?

• Are scalp cooling caps an option for me?

• What can I do to manage hair loss or cope with the changes?

These conversations can help you understand your options and prepare both emotionally and practically. Remember, you have every right to ask questions and advocate for your needs—this is your body, your treatment, and your journey. Your care team is there to support you, and no question is too small.

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Written by Toma Oganezova, MD