A significant new study published in JAMA Dermatology suggests that nicotinamide supplements, a form of vitamin B3, could substantially reduce the risk of repeat non-melanoma skin cancers. This finding, spearheaded by Lee Wheless, MD, PhD, and his team, aims to clarify previous conflicting research on the supplement's efficacy, offering a promising additional strategy for individuals with a history of the disease, though experts continue to emphasize that sun protection remains paramount.

Nicotinamide, also known as niacin, or vitamin B3, is naturally present in foods like poultry, fish, and certain grains and seeds. Once ingested, it converts into nicotinamide adenine dinucleotide (NAD), a crucial coenzyme involved in vital cellular processes such as energy production, cellular communication, and, critically, DNA repair. The underlying principle behind its cancer-preventive potential lies in its ability to enhance the body's natural DNA repair mechanisms. As explained by Dr. Wheless, UV exposure from the sun causes DNA damage, and if this damage isn't promptly repaired, it can lead to mutations that ultimately result in skin cancer. By improving these repair processes, nicotinamide may help prevent the formation of new cancers.

The new research investigated over 33,000 Veterans Health Administration patients who had previously experienced at least one non-melanoma skin cancer. The study compared more than 12,000 individuals who took 500-milligram nicotinamide supplements twice daily for a minimum of one month against approximately 21,000 who did not. Researchers specifically tracked new diagnoses of basal cell carcinoma and cutaneous squamous cell carcinoma, the two most common forms of skin cancer. Overall, nicotinamide supplementation was associated with a 22% reduction in new cutaneous squamous cell carcinomas and a 14% lower risk of new skin cancers across the entire study group, though it showed no reduction in basal cell carcinomas when viewed in this broader context.

However, a more focused analysis revealed a more dramatic impact for "early adopters"—patients who began taking nicotinamide after their very first skin cancer diagnosis. For this subgroup, supplementation was linked to a "huge benefit," exhibiting over a 50% reduction in the risk of subsequent skin cancer, irrespective of the specific type. Dr. Wheless noted that the protective effect seemed to diminish with each additional prior cancer diagnosis, completely disappearing after approximately seven previous cancers, suggesting earlier intervention may yield greater benefits.

Leading dermatologists have reacted positively to the findings. Kelly Nelson, MD, a professor of dermatology and internal medicine at the University of Texas MD Anderson Cancer Center, called the findings "very important" and expressed hope that the manuscript would change clinical practice. Rajani Katta, MD, a Texas-based dermatologist, echoed this sentiment, calling the supplement "very promising," especially given her general caution regarding supplement use. Many dermatologists already recommend nicotinamide to high-risk patients, but this large, well-designed study provides stronger evidence to support such recommendations.

Despite the encouraging results, both Dr. Nelson and Dr. Katta highlighted areas for further investigation. There is currently insufficient data to determine whether nicotinamide supplementation benefits individuals who have never had skin cancer or those with melanoma, a less common but more aggressive form of the disease. Furthermore, while the study suggested nicotinamide is safe, Dr. Katta emphasized the need for more long-term safety data and studies involving more diverse populations, as the current study group was predominantly white and male. Both experts unequivocally stressed that sun-protective behaviors—such as wearing sunscreen and avoiding excessive UV exposure—remain the most crucial and primary defenses against skin cancer, asserting that dietary choices or supplements cannot counteract significant UV radiation exposure. Patients considering nicotinamide should consult their doctor first.