Tanning Beds Triple Your Melanoma Risk—And Scientists Finally Know Why

A groundbreaking study has shown that tanning bed use increases melanoma risk by nearly threefold, and for the first time, scientists have identified exactly how these devices damage skin cells far beyond what ordinary sunlight can reach. Melanoma, the deadliest form of skin cancer, kills approximately 11,000 people in the United States each year. Despite decades of warnings, the indoor tanning industry has argued that tanning beds pose no greater risk than sun exposure—but new research from Northwestern Medicine and the University of California, San Francisco, published in Science Advances, definitively challenges that claim.

How Do Tanning Beds Cause More Damage Than Sunlight?

Researchers led by Dr. Pedram Gerami, the IDP Foundation Professor of Skin Cancer Research at Northwestern, conducted a comprehensive study comparing roughly 3,000 tanning bed users with 3,000 age-matched controls who had never used indoor tanning. The findings were striking: melanoma was diagnosed in 5.1 percent of tanning bed users compared with 2.1 percent of non-users. After accounting for age, sex, sunburn history, and family history, tanning bed use remained associated with a 2.85-fold increase in melanoma risk.

What makes this study particularly significant is how researchers discovered the biological mechanism behind this increased risk. Using advanced single-cell DNA sequencing technology, scientists examined melanocytes—the pigment-producing skin cells where melanoma begins—from three groups: 11 patients with long histories of indoor tanning, nine age-matched controls who had never used tanning beds, and six cadaver donors for additional comparison. The results were sobering: skin cells from tanning bed users carried nearly twice as many mutations as those from controls and were more likely to contain melanoma-linked mutations.

"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," said Dr. Gerami. "That has never been shown before." The critical difference between tanning bed exposure and sun exposure lies in the breadth of damage. "In outdoor sun exposure, maybe 20 percent of your skin gets the most damage," Dr. Gerami explained. "In tanning bed users, we saw those same dangerous mutations across almost the entire skin surface".

Why Are Melanomas Appearing in Unexpected Places?

One of the most revealing findings involved where melanomas developed in tanning bed users. Patients were more likely to develop melanoma on sun-shielded body sites, such as the lower back and buttocks—areas that typically remain protected from outdoor sun exposure. This pattern provided strong evidence that tanning beds create a broader field of DNA injury than sunlight alone, affecting skin that would normally be shielded from ultraviolet radiation.

This discovery has profound implications for how we understand tanning bed risk. The mutations found in tanning bed users weren't confined to exposed skin; they appeared across nearly the entire skin surface, suggesting that the ultraviolet radiation from these devices penetrates and damages skin cells in ways that natural sunlight does not.

What Should People Who Used Tanning Beds Do Now?

Dr. Gerami emphasizes that anyone who frequently tanned earlier in life should take specific preventive steps. Key recommendations include: Schedule a Total-Body Skin Exam: Anyone with a history of frequent tanning should have a comprehensive skin examination by a dermatologist to identify any existing precancerous changes or early-stage melanomas. Establish Routine Monitoring: Depending on your dermatologist's assessment, you may need regular skin checks to catch any changes early, when treatment is most effective. Know Your Skin: Become familiar with your moles and skin lesions, and report any new growths, color changes, or unusual bleeding to your dermatologist promptly. The urgency of these recommendations is underscored by real patient experiences. One study participant, 49-year-old Heidi Tarr from the Chicago area, used tanning beds heavily during high school—two to three sessions per week—because she believed it made her look beautiful. Decades later, she was diagnosed with melanoma and has since undergone more than 15 additional biopsies as new moles appeared. "The biopsies can be painful, but the mental anxiety is worse," she said. "You're always waiting for the call that it's melanoma again".

What Policy Changes Are Experts Calling For?

Based on the biological and clinical evidence, Dr. Gerami and other dermatologists are advocating for significant policy changes. Their recommendations include: Ban Tanning Beds for Minors: At minimum, indoor tanning should be illegal for anyone under 18, as most patients began tanning when they were young, vulnerable, and lacked the knowledge to understand the risks. Implement Cigarette-Style Warnings: Tanning beds should carry warnings similar to those on cigarette packages, clearly stating that use may result in skin cancer and melanoma. Recognize the Carcinogen Classification: The World Health Organization has classified tanning beds as a Class 1 carcinogen—the same level as smoking and asbestos—yet public awareness remains low. "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," Dr. Gerami noted. "They feel wronged by the industry and regret the mistakes of their youth".

The research was funded by the National Institutes of Health, the Department of Defense Melanoma Research Program, the Melanoma Research Alliance, and several private foundations, underscoring the scientific community's commitment to understanding and preventing this preventable cancer. For anyone with a history of tanning bed use, the message is clear: talk to your dermatologist about screening and monitoring, and help younger generations understand the real risks before they make the same choices.