A new study from the University of California San Diego has found that UV-emitting nail polish dryers used to cure the chemicals used in gel manicures may cause cancer.
Ultraviolet (UV) light has wavelengths between 10 nm and 400 nm. The Earth’s stratospheric ozone usually blocks wavelengths below 280 nm. The ultraviolet light that reaches the Earth’s surface is between 280 nm and 400 nm. The International Agency for Research on Cancer has classified broadband UVA 315–400 nm as a Group 1 carcinogen.
The causal relation between skin cancer and irradiation with ultraviolet-emitting tanning devices is well documented, but the use of UVA light in nail dryers has received little attention and could pose a significant public health risk. A spectrum of ultraviolet light (340-395nm) is used to cure the chemicals used in gel manicures. Tanning beds, known to cause skin cancer, use a different spectrum of UV light (280-400nm). This is the first in-depth study of the longer wavelength’s potential mutagenic and cancer-causing effects.
To evaluate the impact of the ultraviolet light used in nail polish dryers on mammalian cells, researchers used a 54-Watt ultraviolet nail drying MelodySusie machine with six bulbs in 20-minute sessions on three different cell lines, including adult human skin keratinocytes, human foreskin fibroblasts, and mouse embryonic fibroblasts. The ultraviolet light wavelengths emitted by this machine are between 365 and 395 nm. The three cell types were exposed to two different conditions: acute exposure and chronic exposure. Petri dishes containing one of the cell types were placed under the nail polish dryer for a 20-minute session, removed for one hour to return to their steady state, and then returned for an additional 20-minute session to replicate acute exposure. To replicate chronic exposure, the cells were placed under the machine for 20 minutes a day for three days.
Cell death, damage, DNA mutations, mitochondrial dysfunction, and high levels of reactive oxygen species occur under both conditions, with more severe impacts in the chronic exposure group. The researchers concluded that the use of these ultraviolet light-emitting devices for one 20-minute session led to between 20 and 30 percent cell death, while three consecutive 20-minute exposures caused between 65 and 70 percent of the exposed cells to die. Genomic profiling revealed higher levels of somatic mutations in the irradiated cells, with patterns of mutations similar to those that are present in melanoma patients.
The results of this study strongly suggest that radiation emitted by ultraviolet light-nail polish dryers may cause cancers of the hand and may increase the risk of early-onset skin cancer. Ultraviolet light exposure to the skin may also cause damage to white blood cells circulating through the small capillaries just below the skin’s surface. However, large-scale epidemiological studies are urgently needed to understand the scope of these risks fully. As a Professor at Harvard Medical School, I pioneered advanced methods to study ultraviolet light damage to DNA. With plenty of alternatives to gel manicures that require curing via ultraviolet-light nail polish dryers, I would encourage everyone to consider these risks during their next trip to the nail salon and select a different option.