A cold cap is a device worn on the head during chemotherapy to reduce or prevent hair loss. It works by cooling the scalp to slow blood flow to hair follicles, limiting their exposure to chemotherapy drugs. Cold caps are the only proven method for keeping hair during cancer treatment, and they’ve become increasingly available at infusion centers across the U.S. since receiving FDA clearance.
How Scalp Cooling Prevents Hair Loss
Chemotherapy drugs travel through the bloodstream and attack fast-growing cells, which includes hair follicles. Cold caps lower the scalp’s temperature by a few degrees before, during, and after each infusion. This cooling causes blood vessels in the scalp to constrict, reducing blood flow to as little as 20 to 40 percent of the normal rate. With less blood reaching the hair follicles, less of the chemotherapy drug reaches them too.
The reduced temperature also slows down cellular activity in the follicles themselves, making them less vulnerable to the drug’s effects. The combination of restricted blood flow and lowered cell metabolism is what gives cold caps their protective effect.
Machine-Based vs. Manual Caps
There are two main types of scalp cooling systems. Machine-based systems, like those made by Paxman and DigniCap, connect to a refrigeration unit that circulates coolant through a fitted cap at a controlled temperature. The machine adjusts automatically, and a nurse or technician helps with setup. These systems are typically available at cancer centers that have purchased or leased the equipment.
Manual cold caps, by contrast, are stored in dry ice and swapped out by hand every 20 to 30 minutes to maintain the right temperature. They require a caregiver or helper to manage the rotation during treatment. Manual caps carry a small risk of scalp thermal injury if bare skin contacts the frozen cap directly. Some people use an inner cap or headband as a protective barrier to avoid skin darkening or blisters.
What the Experience Feels Like
The cap goes on before chemotherapy starts, stays on throughout the infusion, and remains on afterward for a post-cooling period. That post-cooling window varies depending on the specific drugs being used, typically ranging from two to three hours after the infusion ends. For some drug combinations, you could be wearing the cap for several hours total beyond your actual treatment time.
The most common side effects are feeling cold, mild to moderate headaches, and scalp pain similar to a brain freeze. These are generally manageable. Taking an over-the-counter pain reliever about 30 minutes before the cap goes on can help. Some people also report mild nausea or a sense of claustrophobia from the snug fit of the cap. Serious side effects are rare.
Hair Care Rules During Treatment
Using a cold cap means committing to a strict hair care routine for the entire duration of chemotherapy. The goal is to minimize any stress on already-vulnerable follicles. Memorial Sloan Kettering Cancer Center recommends washing and conditioning hair every two to four days with a fragrance-free shampoo, then patting it dry gently with a soft towel rather than rubbing.
The list of things to avoid is long: no hair dryers, curling irons, straighteners, or hot rollers. No hair spray, dye, bleach, relaxers, or perms. No clips, bobby pins, barrettes, ponytail holders, or scrunchies. No braids, cornrows, or ponytails. You should brush gently with a soft-bristle brush, starting at the ends and working up to the scalp. Many people choose to cut their hair shorter before starting treatment to make the process easier to manage.
Who Should Not Use Cold Caps
Cold caps are cleared for use in patients with solid tumors, meaning cancers that form a mass in a specific organ or tissue, like breast, lung, or ovarian cancer. They are not recommended for blood cancers such as leukemia or lymphoma, because these cancers involve circulating tumor cells. Cooling the scalp could theoretically create a “sanctuary” where cancer cells are shielded from treatment.
People with cold sensitivity, a condition called cold agglutinin disease (where cold temperatures cause red blood cells to clump), or cryoglobulinemia (where abnormal proteins thicken in cold temperatures) should also avoid scalp cooling. Patients with significant liver dysfunction may not be good candidates either, since impaired liver function can slow the body’s ability to clear chemotherapy drugs, extending the window of exposure.
FDA Clearance
The FDA first authorized scalp cooling for breast cancer patients in 2015. It later expanded clearance to cover all solid tumor cancers, making DigniCap the first cooling system approved for that broader use. This expanded clearance means the technology can now be offered to patients with a wide range of cancer types beyond breast cancer, as long as the tumor is solid rather than blood-based.
Cost and Insurance Coverage
Scalp cooling has historically been expensive out of pocket. Initial estimates placed costs at $1,500 to $2,400 per chemotherapy cycle, and most patients go through multiple cycles. For a full course of treatment, the total could reach several thousand dollars.
Coverage has been improving. In 2021, the American Medical Association introduced billing codes that allowed providers to charge insurers directly for scalp cooling services. The following year, the Centers for Medicare and Medicaid Services established a payment rate for the cap fitting, monitoring, and removal procedure. Today, some Medicare and Medicaid plans cover scalp cooling, and more private insurers are beginning to follow. Many cancer centers are shifting from a self-pay model to billing insurance directly on behalf of patients, which removes some of the financial burden of navigating reimbursement independently. If you’re considering scalp cooling, it’s worth asking your treatment center whether they bill insurance and what your specific plan covers.