Niacinamide (also known as nicotinamide), a common over-the-counter vitamin B3 supplement, may help prevent certain types of skin cancer, according to a large retrospective study of U.S. veterans. The relevant analysis was published in the journal JAMA Dermatology.
The research team analyzed the health records of 33,822 U.S. veterans and found that those who took 500 mg of nicotinamide twice a day for more than 30 days had fewer new skin cancers than those who did not take it.
"Nicotinamide, as a pure vitamin B3 derivative, shows real promise as a skin cancer prevention tool," said Dr. Yousuf Mohammed, senior researcher and project leader at the Fraser Institute at the University of Queensland in Australia. "This large retrospective study of veterans' data showed that those taking oral nicotinamide had a 14% reduction in the risk of new skin cancers."
Niacinamide is a non-flushing form of vitamin B3 (unlike niacin) and functions biologically as a precursor to NAD⁺, an important coenzyme in cellular energy production and repair. Previous experimental and clinical studies have found that nicotinamide can enhance the repair capacity of skin DNA after ultraviolet (UV) irradiation and inhibit UV-induced immunosuppression. These mechanisms may be the basis of its anti-cancer effect.
Dr. Mohammed added: "For clinicians, nicotinamide has the advantages of convenience, cost-effectiveness, and a good safety profile. Unlike systemic retinoids or invasive treatments, nicotinamide is cheap, easy to obtain, and has mild side effects."
This study analyzed electronic health records from the U.S. Department of Veterans Affairs (VA) between October 1999 and December 2024. Of the 33,822 veterans, 12,287 took nicotinamide continuously (500 mg twice daily for more than 30 days) and 21,479 did not.
The research team used propensity score matching to balance many factors that may affect the risk of skin cancer, including skin cancer history (number of occurrences, time of onset), age, gender, race, use of retinoic acid drugs, and history of chronic lymphocytic leukemia or organ transplantation. Hierarchical Cox models were then used to evaluate the association between nicotinamide and the risk of new skin cancer.
The analysis also evaluated the cancer-preventive effects of taking nicotinamide at different time points (first, second, or after multiple episodes) for three common skin cancer types, combined with personal skin cancer incidence history.
Main findings
Overall risk reduction: In the matched cohort, taking nicotinamide was associated with a 14% reduction in the risk of new skin cancers.
The timing is important: For those who start taking it after the first onset of skin cancer, the risk of subsequent skin cancer is reduced by about 54%, but the protective effect is weakened for those who take it again after multiple episodes of skin cancer.
Cancer types: Patients with both basal cell carcinoma and squamous cell carcinoma of the skin showed reduced risk, with the greatest effect for squamous cell carcinoma.
Transplant recipients: Among organ transplant patients who are at high risk for immunosuppression, the overall risk reduction is not significant, but there is evidence of a decrease in the incidence of squamous cell carcinoma in early adopters.
Dr. Mohammed concluded: "The greatest impact was on squamous cell carcinoma, with a risk reduction of more than 20%. Especially for patients who took nicotinamide after the first onset of skin cancer, the risk dropped by nearly 50%. This finding highlights that taking it earlier is more conducive to improving the protective effect."
Experts believe that over-the-counter niacinamide (500 mg twice daily) can modestly reduce the risk of new skin cancers as a low-cost, safe adjunct. However, it cannot replace basic protective measures such as sun protection and routine dermatological examinations.
Because these conclusions are based on a retrospective analysis, mainly in older white men, the scope of the benefit and specific effects require further research in prospective, randomized controlled trials, and in high-risk groups (such as organ transplant recipients).