A commonly available form of vitamin B3, nicotinamide, was associated with fewer non‑melanoma skin cancers in a large observational study of more than 33,000 U.S. veterans published in JAMA Dermatology. Overall use of nicotinamide corresponded to about a 14% reduction in future non‑melanoma skin cancers. The biggest benefit appeared in people who began nicotinamide after a first skin cancer diagnosis, whose risk of another cancer fell by more than half.
These results add to earlier evidence, including a 2015 randomized trial of 386 participants that found fewer new skin cancers with nicotinamide compared with placebo. The new, larger study provides real‑world supportive data suggesting a protective effect against UV‑related, non‑melanoma skin cancers.
Why it may work: nicotinamide helps restore cellular energy carriers (NAD+ and ATP) that are used during DNA repair, which can help skin cells fix UV‑induced damage more effectively. It also appears to support local immune surveillance in the skin and reduce inflammation—mechanisms that could decrease the chance that UV‑damaged cells survive and progress to cancer.
Important limitations: the study was retrospective, so unmeasured factors—such as differences in sun exposure, sun protection behavior, medication adherence, and frequency of dermatology follow‑up—could affect the findings. The veteran cohort was older and predominantly male, which limits generalizability to women and younger populations. Exposure was assessed via prescription and record data rather than direct measures of whether patients actually took the pills. Benefits were also less clear in some subgroups, such as certain immunosuppressed individuals and solid‑organ transplant recipients.
Clinical takeaways: dermatologists view nicotinamide as a possible adjunctive measure, not a replacement for established prevention strategies. Core prevention remains daily broad‑spectrum sunscreen (SPF 30 or higher), protective clothing and hats, avoiding peak sun hours, and routine skin checks. For people at higher risk or with prior non‑melanoma skin cancer, nicotinamide may offer an additional internal layer of protection by supporting DNA repair and reducing inflammation.
When used in studies, the typical dose is 500 mg twice daily, and consistent, ongoing use appears important to potentially see benefit. Patients should discuss individual risk factors, current medications, and overall health with their clinician before starting nicotinamide. Regular self‑exams and prompt evaluation by a dermatologist for any new, changing, or symptomatic spots remain essential, since early detection improves outcomes.
