Cooling caps are massively popular with European chemo patients and have been making inroads into the US, but two studies published Tuesday in the Journal of the American Medical Association offer some of the first clinical proof of their effectiveness. In one study, approximately two-thirds of breast cancer patients lost less than half their hair; in the other study, approximately half of breast cancer patients lost less than half their hair. The New York Times reports 5% of patients kept all their hair. The differences in effectiveness between the studies could have to do with the cooling caps being used, the medical centers applying the caps, and the chemo drugs involved, according to HealthDay News. The studies were funded by two different companies that manufacture cooling caps.
Cooling caps are affixed to patients' heads before, during, and after chemo; a machine cycles cooling liquid through the caps. While researchers aren't exactly sure how the caps prevent hair loss, NPR reports, one theory is they restrict blood vessels in the scalp, reducing the amount of chemo that reaches the hair follicles. About half of breast cancer patients say hair loss is the most daunting part of chemo, and 8% say they would turn down chemo in order to keep their hair. One breast cancer survivor who used a cooling cap says it has psychological benefits. She tells the Times that losing their hair makes people "think they're sicker than they actually are." (A dose of magic mushrooms had a big effect on cancer patients.)