A simple vitamin supplement may help prevent recurring skin cancers. Researchers found that nicotinamide, a form of Vitamin B3, reduced the chance of developing another non-melanoma skin cancer by more than half in people who began taking it after their first diagnosis.

The study followed nearly 34,000 U.S. veterans. Participants who took 500 mg of nicotinamide twice daily had a 54 percent lower risk of developing another cancer. Overall, risk dropped by about 14 percent, with the strongest results seen in cutaneous squamous cell carcinoma. Dermatologists say the supplement is safe, inexpensive, and most effective when started soon after diagnosis.

Experts caution that nicotinamide’s benefits have only been proven in people who already had skin cancer, and more research is needed to see if it helps high-risk people without a diagnosis. Still, doctors now feel more confident recommending it to patients as a low-cost, low-risk option that could help curb rising skin cancer rates.