Since arriving on the market around 2010, gel manicures have become a staple in nail salons across the US and many parts of the world, and it’s easy to see why. Compared to traditional nail polish, gel variants are more resilient to damage and smudging, and they retain their shine until you remove the polish from your fingernails. Best of all, if you’re the impatient sort, you don’t need to wait an hour or more for a gel manicure to dry. Those benefits all come courtesy of the way the polish cures. Instead of waiting for a gel polish to dry naturally, you place your hands under a UV light, which activates the chemicals inside the gel, causing it to harden.

While the dangers of UV light — particularly in tanning settings — are well-known, before this week scientists had not studied how the ultraviolet lights used to cure gel polishes might affect human skin. You might think what we know about tanning beds applies here, but the devices used by nail salons emit a different spectrum of ultraviolet light. A group of researchers from the University of California San Diego decided to study the devices after reading an article about a beauty pageant contestant who was diagnosed with a rare form of skin cancer.

Using different combinations of human and mouse cells, the researchers found a single 20-minute session with an ultraviolet nail polish dryer led to as many as 30 percent of the cells in a petri dish dying. Three consecutive 20-minute sessions saw 65 to 70 percent of the exposed cells dying off. Among the remaining cells, the researchers saw evidence of mitochondrial and DNA damage, in addition to mutations that have been seen in skin cancer patients.

“Our experimental results and the prior evidence strongly suggest that radiation emitted by UV-nail polish dryers may cause cancers of the hand and that UV-nail polish dryers, similar to tanning beds, may increase the risk of early-onset skin cancer,” the researchers write in a study published in the journal Nature Communications on Tuesday. They warn that a longer epidemiological study is needed before they can conclusively say the use of UV drying devices leads to an increased risk of skin cancer, adding “it is likely that such studies will take at least a decade to complete and to subsequently inform the general public.” 

You might think the advice here is to avoid UV dryers, but it’s not so simple. Gel manicures have become an industry standard for a reason. For many people, regular nail polish starts to chip off after a day or so, making a traditional manicure often not worth the time, money or effort.