CHICAGO—Tanning bed use is tied to almost a threefold increase in melanoma risk, and for the first time, scientists have shown how these devices cause melanoma-linked DNA damage across nearly the entire skin surface, reports a new study led by Northwestern Medicine and University of California, San Francisco.
How common is tanning bed use these days? While spray tanning and self-tanners have become the industry standard as consumer awareness surrounding skin health is at an all, other trends have fed into a Y2K-revival that's feeding younger sun-bugs into the tanning beds, as re-popularized by platforms like TikTok and Instagram, where people post their tanning routines and tips.
Melanoma in the US
Melanoma, the deadliest skin cancer, kills about 11,000 in the US each year. The tanning bed industry has historically argued that tanning beds are no more harmful than sunlight, but this new study challenges those claims by showing how tanning beds, at a molecular level, mutate skin cells far beyond the reach of ordinary sunlight.
“Even in normal skin from indoor tanning patients, areas where there are no moles, we found DNA changes that are precursor mutations that predispose to melanoma,” says study first author Dr. Pedram Gerami, professor of skin cancer research at Northwestern University Feinberg School of Medicine. “That has never been shown before.”
The study
Gerami, who also directs the melanoma program in dermatology at Northwestern, has been treating melanoma patients for 20 years. He and his team found that melanoma was diagnosed in 5.1% of tanning bed users compared with 2.1% of non-users.
Tanning bed users were also more likely to develop melanoma on sun-shielded body sites, such as the lower back and buttocks. To test the hypothesis that tanning beds may cause broader DNA injury than sun exposure, the team used new genomic technologies to perform single-cell DNA sequencing on melanocytes across three donor groups.
DNA sequencing
The first group included 11 of Gerami's patients, all of whom had long histories of indoor tanning. The second group consisted of nine patients who had never used tanning beds but were otherwise matched for age, sex and cancer risk profiles. The third group comprised six cadaver donors to complete the control group.
The scientists sequenced 182 individual melanocytes and found skin cells from tanning bed users carried nearly twice as many mutations as those from the control group and were more likely to contain melanoma-linked mutations.
Gerami adds: “In outdoor sun exposure, maybe 20% of your skin gets the most damage. In tanning bed users, we saw those same dangerous mutations across almost the entire skin surface.”
Donated biopsy tissues
The study would not have been possible without the generosity of Gerami’s patients who donated their biopsies. One patient, 49-year-old Heidi Tarr from the Chicago area, used tanning beds two to three times a week throughout high school.
Decades later, as a mother in her thirties, she noticed a mole on her back, which led to a melanoma diagnosis that required surgery, years of follow-ups and 15 biopsies with the appearance of new moles. Even though biopsies can be painful and anxiety-inducing, once Tarr heard about Gerami's study, she didn't hesitate before volunteering.
The tanning bed industry
After seeing the biological and clinical evidence side by side, Gerami says the need for policy change is clear.
“Most of my patients started tanning when they were young, vulnerable and didn’t have the same level of knowledge and education they have as adults,” he notes. “They feel wronged by the industry and regret the mistakes of their youth.”
Gerami goes on to say that tanning beds should carry warning labels akin to those on cigarettes. He also recommends that anyone who's frequently tanned should have a full-body skin exam by a dermatologist, who can recommend routine skin checks if needed.
Source: Northwestern. (2025, December 12). Tanning beds triple melanoma risk, potentially causing broad DNA damage [Press release]. https://news.northwestern.edu/stories/2025/12/tanning-beds-triple-melanoma-risk-potentially-causing-broad-dna-damage?fj=1
