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A common, over-the-counter form of vitamin B3 has emerged as an inexpensive ally in protecting us from skin cancer, lowering the risk by an average of 14% and increasing to a massive 54% for anyone who has previously had a positive diagnosis. This latest study of more than 33,000 patients supports earlier evidence that emerged in a 2015 Australian trial.
Researchers from Vanderbilt University Medical Center conducted a large real-world analysis of US veterans, which looked at the health records of 33,822 individuals, comparing those prescribed niacinamide (typically 500 mg twice daily for more than 30 days) with matched patients who didn’t take it.
Overall, niacinamide – also known as nicotinamide, a vitamin B3 form found in food and supplements that supports cellular energy, DNA repair and healthy skin – was associated with a 14% lower risk of developing skin cancer. When people began nicotinamide after having earlier received a positive skin cancer diagnosis, the reduction in risk was 54%. What's more, the effect was seen in both basal cell carcinoma and cutaneous squamous cell carcinoma, with the largest drop in squamous cell cancers.
“There are no guidelines for when to start treatment with nicotinamide for skin cancer prevention in the general population," said corresponding author Lee Wheless, M.D., assistant professor of Dermatology and Medicine at Vanderbilt University Medical Center. "These results would really shift our practice from starting it once patients have developed numerous skin cancers to starting it earlier. We still need to do a better job of identifying who will actually benefit, as roughly only half of patients will develop multiple skin cancers."
While basal cell carcinoma, which generally affects areas of the skin that have endured longterm exposure to the Sun, develops slowly, they can be easily missed for some time and surgery can be significant. (In 2024, I had surgery to remove one measuring 0.4 cm in diameter, which required a deep and wide excision, and around 20 subcutaneous and surface stitches.) Cutaneous squamous cell carcinoma, meanwhile, are cancerous growths on a more surface layer of skin. These, along with melanoma, make up the three malignant skin cancers.
People tend to underestimate the impact and seriousness of non-melanoma cancers. The US spends more than US$8 billion each year in treating skin cancer – and a majority of that cost ($4.8 billion) is to address non-melanoma types.
In general, niacinamide has been shown to help skin cells repair UV-induced DNA damage, and it blunts some of the immunosuppressive effects of sunlight. While observational, so causation can't be proven, this study is by far the biggest dataset yet on niacinamide's everyday performance outside of controlled clinical trials. The veteran cohort also skews older and male (average age 77 and predominantly white men), and the researchers caution that studies on a more diverse demographic are needed to see if these results can be replicated more broadly.
However, it does echo the findings of the groundbreaking 2015 ONTRAC phase-3 trial in Australia, which demonstrated that 500 mg of niacinamide twice daily lowered the incidence of new non-melanoma skin cancers by about 23% over 12 months in 386 high-risk adults with prior skin cancers. And this protective factor diminished once the individuals discontinued the treatment.
While the researchers urge that this is no replacement for covering up and applying sunscreen to exposed skin, for people who’ve had a first basal or squamous cell carcinoma removed, a daily niacinamide regimen is emerging as a practical, inexpensive way to lower the odds of a recurrence. And this study gives clinicians and patients more real-world numbers to weigh when deciding whether these supplements could be of benefit.
"The results of this cohort study suggest that there is a decreased risk of skin cancer among patients treated with nicotinamide, with the greatest effect seen when initiated after the first skin cancer," noted the researchers.
"Nicotinamide, a simple vitamin B3 derivative, is showing real promise as a practical tool for skin cancer prevention," said Dr Yousuf Mohammed, a Senior Research Fellow at the University of Queensland. "These findings highlight that timing matters; starting earlier may be the key to stronger protection. For clinicians, the appeal of nicotinamide lies in its accessibility, safety, and tolerability. Unlike systemic retinoids or invasive field therapies, nicotinamide is inexpensive, over-the-counter, and free from significant side effects.
"Overall, these results reinforce what many dermatologists have long suspected, nicotinamide is an underutilized, low-risk intervention that can make a difference in reducing skin cancer burden, especially for patients with an early history of disease," he added.
The research was published in the journal JAMA Dermatology.
