Immunotherapy rarely causes hair loss. Unlike chemotherapy, which commonly leads to complete hair loss, most people receiving immunotherapy keep their hair. In the small number of cases where hair loss does occur, it is usually mild (such as thinning or patchy loss) and hair often grows back after treatment ends. For commonly used immunotherapy drugs like checkpoint inhibitors, studies suggest hair loss occurs in only about 1% to 1.6% of patients.

Why Chemotherapy Causes Hair Loss More Than Immunotherapy

Chemotherapy works by targeting rapidly dividing cells in the body. While this helps destroy cancer cells, it also affects other fast-growing cells, like those in hair follicles. As a result, hair loss is a common and expected side effect of chemotherapy.

Immunotherapy works differently. Instead of directly attacking cancer cells, it helps your immune system recognize and fight cancer. Because it does not target rapidly dividing cells in the same way, hair follicles are usually not affected, making hair loss much less common.

Learn more about hair loss and cancer treatment: Hair Loss (Alopecia) — American Cancer Society

Which Immunotherapy Drugs Are More Likely to Cause Hair Loss?

The likelihood of hair loss can vary depending on the type of treatment:

• Checkpoint inhibitors (such as Keytruda® and Opdivo®): These are among the most commonly used immunotherapy drugs and have the lowest risk of hair loss, reported in about 1–1.6% of patients.
• Atezolizumab (Tecentriq®): This medication may have a slightly higher chance of causing hair thinning compared to other checkpoint inhibitors, though the risk is still relatively low.
• Combination immunotherapy (for example, a CTLA-4 inhibitor used with a PD-1 inhibitor): Using multiple immunotherapy drugs together can increase the risk of side effects, including hair loss, although it remains uncommon.
• Targeted therapies (such as tyrosine kinase inhibitors, VEGF inhibitors, and CDK 4/6 inhibitors): These are sometimes grouped with immunotherapy but work differently and are more likely to cause hair thinning or loss than traditional immunotherapy drugs.

For more detailed medical information, see: Alopecia and Hair Damage Induced by Oncological Therapy — PubMed

If you’re starting immunotherapy and are concerned about side effects like hair loss, your healthcare provider or specialty pharmacy team can help you understand what to expect and how to manage any changes during treatment.