Health experts warn that it's not safe to use tanning beds. These people just can't quit the habit.

“Humans are weird, I am paying money to lay in a bright tube that will give me cancer,” Linnea Bendiksen wrote in a TikTok video she posted last spring that she recorded while inside of a tanning bed. That viral video has received more than 300,000 likes and is one of the many examples of tanning beds making a comeback on TikTok, including a recent video in which Kim Kardashian shows off her workspace and says, “Of course I have a tanning bed in my office.”

Dr. Muneeb Shah, a board-certified dermatologist also known as the “DermDoctor” to his more than 18 million TikTok followers, finds videos like Bendiksen’s and Kardashian’s frustrating because they downplay the serious risks of tanning beds, which he experienced personally. Shah frequently used tanning beds as a teenager, and, at 31, he self-diagnosed himself with skin cancer when he noticed a pink, itchy bump on his chest that bled when he scratched it. “I learned a lot about what patients go through and what it actually feels like when you have [skin cancer] removed, and that’s also why I’m on social media very often trying to tell people the risks of tanning,” Shah tells Yahoo Life.

Is using a tanning bed really so bad?

Yep — the risks are significant. Using a tanning bed, even just once, increases a person’s risk for developing skin cancer, and this association becomes stronger the younger people are when they first begin using them. “Tanning beds are bad — period," Dr. Allan Halpern, chief of the Dermatology Service at Memorial Sloan Kettering Cancer Center, tells Yahoo Life. "There is a reason that the [Food and Drug Administration] strongly warns against their use and that 40-some-odd states have legislation against their use under the age of 18, and that is because ultraviolet (UV) radiation itself is the primary cause of skin cancer.” Using tanning beds has also been associated with eye inflammation and aging skin.

UV light comes in three main types: UVA, UVB and UVC. “UVC is something that nobody uses except for sterilizing things because it’s quite toxic," Halpern explains. "[UVB] are burning rays, and [UVB] is why you get a sunburn. [UVA] can give you a tan without a sunburn, but all ultraviolet radiation damages the DNA in your cells and can cause skin cancer."

Halpern adds, "To be fair to the tanning bed industry, people honestly thought it was only UVB that was bad and caused skin cancer, and people developed UVA tanning beds with the idea that it would protect you from the sun." But that’s not true. “A tan itself doesn’t happen until you damage your DNA," he says.

So what's the appeal?

If the risk of using tanning beds is so great, why are people still using them?

“I love how a tan makes me feel, and the tanning bed is an easy option to keep that color up in the wintertime,” Bendiksen, the 21-year-old TikToker from Norway, tells Yahoo Life via email. Europe has even higher rates of tanning bed use than the U.S., and despite Norway having regulations against minors using tanning beds, Bendiksen says she used one for the first time when she was just 14. She started going to tanning salons regularly over the past couple of years.

“I started doing it because of TikTok,” Caroline (who prefers to use only her first name) tells Yahoo Life. The people in the before-and-after tanning videos she saw on TikTok looked “incredible,” the Texas-based college junior says. Caroline used a tanning bed for the first time last August, hoping it would help her keep her summer tan. She ended up getting a bad burn, and vowed to never go back because it didn't seem safe.

But last month she wanted to get some color before spring break, and didn’t want to use fake self-tanner because she thought it would be too splotchy. And so Caroline decided to try a tanning bed again — and has been going back every other day. “I know there’s obviously bad things that happen when you use tanning beds, but I also know that there are some health benefits," she says. "For me, I like that in the winter when it’s gross outside I can feel a bit down, so I feel like it boosts my mood a little bit.” Being tan also makes Caroline feel more confident.

Are there benefits to using a tanning bed?

Studies have found that people are motivated to use sunbeds because of aesthetic reasons — such as looking tanner or treating skin conditions like acne, or as in Kardashian's case, psoriasis — as well as for perceived psychological (feeling more confident) and health benefits (increasing vitamin D exposure). The misperception that any possible benefits of using tanning beds outweigh the risks is common, especially on TikTok — but Shah says that's not the case.

“The risk ratio [of skin cancer] for both psoriasis and acne are just not worth it,” he says. “There are some studies that show that UVB from the sunlight, or UVB light in general, can help with acne because light can kill the acne-causing bacteria, but there are also studies that show tanning and light can make acne worse."

Shah adds that while dermatologists have previously recommended tanning beds as a form of light therapy to help with psoriasis, advancements in dermatology have meant that that's no longer standard practice. Also, “one of the issues [with tanning beds] is the wavelength of light that treats psoriasis well is UVB light, and most tanning beds are in the UVA range, so it’s not really even in the correct range," he notes. "So you’re getting a lot of damage from a broad spectrum of light and not getting the benefits."

That was 33-year-old Brittany’s experience. She’s had psoriasis since she was 3. In high school, she received light booth treatment in her dermatologist’s office. But when she went away to college, she found that she wasn't near any clinics that offered similar phototherapy. Her dermatologist recommended she use a tanning bed instead, which she did under his direction for six to eight months. The sunbed approach was ineffective, however, and Brittany (who asked to not use her last name) says she worried about the increased risks of skin cancer, which runs in her family. “I would definitely recommend going through your doctor’s recommendation before you use a tanning bed,” Brittany, who now uses medication to treat her psoriasis, tells Yahoo Life.

Shah has personally lived through the consequences of using a tanning bed; he also sees them every day in his office as he diagnoses more and more 30-year-olds with skin cancer. It’s the same for Halpern. He says that when he first started practicing decades ago, he rarely saw skin cancer in people in their 20s and 30s, but it’s quite common now. “It’s hard to convince young people about downstream effects because it’s not how they’re wired," Halpern says. "And, frankly, that’s why the bigger challenge is finding influencers out there who are pushing an aesthetic that is healthier.”