UV nail polish drying devices may cause cancer-causing mutations, study warns

A common accessory of salons and home grooming kits, ultraviolet (UV) nail polish dryers are like little tanning beds for your hands.

These portable lamps emit rays of ultraviolet light to quickly dry nail polish formulas, known as shellacs, or gels, so they don’t smudge furniture.

But a new study warns that these devices pose a bigger public health problem than previously thought — and can cause cancer, just like tanning beds.

Researchers at the University of California San Diego found that its use leads to cell death and cancer-causing mutations in human cells.

Despite this, UV nail lamps tend to be sold without much regard to their potential health risks, according to the experts, who published their study in Nature Communications.

“If you look at the way these devices are presented, they are marketed as safe, nothing to worry about,” said Ludmil Alexandrov, professor of bioengineering and cellular and molecular medicine at UC San Diego.

“But, as far as we know, no one has really studied these devices and how they affect human cells at the molecular and cellular levels until now.”

Professor Alexandrov and his colleagues noticed reports in medical journals of people who frequently get gel manicures, such as beauty pageant contestants and beauticians, who now have rare cancers on their fingers.

“What we saw was that there was no molecular understanding of what these devices were doing to human cells,” he said.

UV light, which has a shorter wavelength than visible light, is separated into three classifications depending on its wavelength – UVA, UVB and UVC.

Generally, UV lamps for nails contain lamps that emit wavelengths between 340 and 395 nm – therefore, in UVA support.

UVA, the longer wavelength ultraviolet light, is already known to cause tanning and has been shown to contribute to the development of skin cancer.

Tanning beds use fluorescent lamps that emit mostly UVA, with lower doses of UVB, and have been conclusively shown to be carcinogenic, but light from nail lamps has not been well studied despite having a similar wavelength.

For the study, the researchers used two types of human cells – keratinocytes and fibroblasts – in addition to cells extracted from mouse embryos.

In Petri dishes, the three types of cells were exposed to two different conditions – ‘acute exposure’ and ‘chronic exposure’ – under UV nail lamps.

For acute exposure, dishes containing one of the cell types were exposed for 20 minutes before being taken out for an hour for repair or return to their original state and then given another 20-minute exposure.

Meanwhile, under chronic exposure, the cells were placed under the machine for 20 minutes a day for three consecutive days.

The researchers found that a single 20-minute session led to 20 to 30% cell death, while three consecutive 20-minute exposures caused 65 to 70% of exposed cells to die.

Exposure also caused mitochondrial and DNA damage in the remaining cells and resulted in mutations with patterns that can be seen in human skin cancer.

Overall, the results suggest that frequent or repeated use of these devices is harmful to human cells, the team argues.

Unprotected exposure to UVA and UVB rays damages the DNA in skin cells, producing mutations that can lead to skin cancer.

The team admits that UVA can penetrate deeper into the skin and is poorly absorbed by DNA, causing little direct DNA damage compared to UVB.

UVB, by contrast, penetrates the outer layer of the skin and “induces a myriad of DNA lesions,” they say.

Currently, some existing sources on the internet suggest that UV nail lamps are safe.

According to the Food and Drug Administration, UV nail lamps pose a low health risk “when used as directed on the label.”

Meanwhile, a 2014 study in JAMA Dermatology found that the level of UVA exposure associated with a gel manicure every other week is probably not high enough to significantly increase your risk of skin cancer.

Experts at Harvard suggest that using sunscreen or wearing a pair of fingerless gloves during a manicure can give your skin additional protection.

Interestingly, other consumer products use UV light in the same spectrum, including the tool used to cure dental fillings and some hair removal treatments.

But the UC San Diego researchers say UV nail lamps are used much more regularly, making them a bigger concern.

However, a long-term epidemiological study is needed to conclusively state that the use of UV nail lamps increases the risk of skin cancer, they add.

‘Such studies are likely to take at least a decade to complete and then to be released to the general public.’