Shiny, durable, chip-resistant and ideal for masking nail imperfections, gel manicures have become a regular part of many women’s beauty routines.

But gel nail polish needs ultraviolet light to harden, raising concern about the risk of skin cancer when hands, cuticles and nails are regularly exposed to UV rays that can be more powerful than the sun.

LED lamps still emit UV rays

Some salons use UV nail lamps to cure the polish; others use LED lamps. Women may think the LED devices skip or minimize the ultraviolet light, but that’s a big misnomer, said Dr. Chris Adigun, a dermatologist in Chapel Hill, North Carolina, who specializes in nail disorders and who contributed expert advice on the safety of gel manicures for the American Academy of Dermatology.

“Gels are massively popular nationally. They have catapulted the nail salon industry into a whole other stratosphere of revenue,” Adigun told TODAY.

“Gels, by definition, need a UVA exposure to polymerize. So if there’s no UVA, there is no gel manicure.”

Here’s the worry: UVA rays are the most mutagenic wave length range of the UV spectrum, penetrating the skin more deeply than UVB rays and playing a role in skin cancer development and premature skin aging such as wrinkles and sun spots.

To harden gel nail polish, a woman places her hand under a lamp that emits UVA rays for anywhere from 30 seconds to a few minutes, depending on the type of the device.

LED lamps have much shorter curing times, but that’s because the UVA rays they emit are much more intense than regular UV lamps or even the sun, Adigun said. They’re so powerful that she didn’t know how they would compare to the UV exposure people get by being outdoors.

When TODAY recently profiled a 21-year-old woman who received regular gel manicures and discovered she had nail melanoma, one dermatologist called the lamps “like tanning beds for your hands,” though Adigun said they’re a bit different since tanning beds use both UVB and UVA rays.

Can a few minutes under a nail lamp increase skin cancer risk?

“Theoretically yes, because we know that UVA ray exposure increases your risk of skin cancer, and you have to have UVA exposure to cure a gel manicure,” Adigun noted, adding there’s particular concern about the gel manicure exposure adding up over time. Some women go every two weeks.

“But have we actually proven that link? Do we have that cause and effect proven? We don’t.”

Another concern is that there is no standard for how long hands should be kept under the lamp. The devices are not regulated and each proprietary gel polish has its own lamp and own recommended curing time, Adigun said.

A salon may or may not follow the recommendations or have the right kind of lamp. There’s also incentive to keep the hands under the light longer.

“You can imagine a nail salon customer is less likely to complain about a well-cured — potentially over-cured — gel polish manicure than they would an under-cured manicure,” Adigun noted.

Research continues in this area, but since gel manicures are fairly new and it can take decades for skin cancer to develop, the full picture may not be clear for a while.

Long-term exposure to UV nail lamps may have the potential to increase both cancer risk and UV-induced skin aging, a 2013 study found.

A 2014 paper warned longer exposure times led to increased potential for skin damage, but concluded the risk for developing cancer was small.

Another paper profiled two women who had regular exposure to UV nail lights and developed squamous cell carcinoma on their fingers and hands.

As for nail melanoma, it's been thought UV exposure isn't an important risk factor since the nail matrix is underneath the skin. But a 2017 study discovered some nail melanomas contained mutations with a UV signature, surprising experts in the field.

“What this says is that we just don’t know, and that we can’t really conclude for sure that nail melanoma has nothing to do with UV exposure,” Adigun said.

How to protect yourself:

Adigun emphasized she’s not “anti-gel,” and that you can still get gel manicures as long as you protect your skin.

The best way is to cover your hands and fingers with a garment that has a UPF (ultraviolet protection factor) rating, whether it’s a glove with the tips cut off, a shirt or a scarf, she said. TODAY style editor Bobbie Thomas demonstrated gloves especially designed for this purpose that you can buy.

The American Academy of Dermatology also recommends applying a broad-spectrum sunscreen with an SPF of 30 or higher to your hands before getting a gel manicure. Adigun still preferred a physical cover rather than sunscreen because it’s not clear how effective sunscreen is in blocking the intense UVA rays emitted by some of the lamps.

Be aware there are many medications that can increase your sensitivity to UV light, such as doxycycline, an oral antibiotic. People taking these drugs must be extra careful to protect their skin during a gel manicure to avoid blistering or burns on their hands.