Beauty comes at a price, and for long-lasting manicures, that may include skin cancer. One of the more popular services at nail salons involves baking the paint onto the nail under an ultraviolet (UV) lamp – yes, the kind that emits the same aging and skin-damaging light that can cause melanoma and other malignancies. But advice about how safe it is to get that kind of exposure from the occasional (or even weekly) manicure has been conflicting.
A new report from JAMA Dermatology finds that how much UV light you're getting exposed to depends on the bulb you put you fingers under—and they vary wildly.
Unlike previous studies, in which scientists analyzed the amount of UV emitted by single devices, Dr. Lyndsay Shipp, a resident at Georgia Regents University’s Medical College of Georgia, and her colleagues measured the amount of irradiation from nail dryers at 16 nail salons in the U.S. Most salon devices emit more UVA than UVB light, and UVA rays penetrate more deeply into skin. Salons use a range of bulbs, however, that emit vastly different amounts of UVA. Because UVA damage to DNA is cumulative, Shipp and her team also calculated that it could take as few as 24 visits to some salons and as many as 625 to others, to reach the point where the UV light triggers cancer-causing DNA damage. (Many lamps also provided inconsistent UV light: “If you’re sticking your hand in the device, your pinky might get a different amount of UV than your thumb,” says Shipp.)
Shipp acknowledges that more research is needed. For now, that means the risk in drying your manicure under these lamps is variable. A single manicure won't give you skin cancer, obviously, but anyone concerned about — or with a family history of — the disease should consider smearing a little sunscreen on their hands or doing it the old-fashioned way: air drying.