Study links vitamin B3 supplement to lower skin cancer risk in US veterans

A commonly available form of vitamin B3, nicotinamide, was associated with a lower risk of skin cancer in a large retrospective study of US veterans, researchers reported Thursday in JAMA Dermatology.

The analysis of health records from 33,820 veterans found that those who took nicotinamide twice daily for at least 30 days had an overall 16 percent lower risk of developing skin cancer compared with participants who never used the supplement. Among people with a prior skin cancer, treatment with nicotinamide was associated with as much as a 54 percent reduction in the risk of a subsequent cancer, with the largest benefit observed for squamous cell carcinoma (SCC).

Lead and co-author Kimberly Breglio, a dermatologist specializing in immunology, said the timing of initiation was a key factor: patients experienced the greatest benefit when nicotinamide was started after their first skin cancer. "Timing of treatment was a crucial variable in our study, with patients experiencing benefit only when initiated after the first few skin cancers," she said, adding that the findings aligned with prior risk estimates showing a 30 to 50 percent reduction in risk in earlier research.

The study cohort comprised 33,820 veterans, just over a third of whom had documented nicotinamide use. The remainder—21,479 participants—had no recorded use of the supplement. Investigators used electronic health records to compare rates of subsequent skin cancers between users and nonusers and adjusted for available clinical variables.

Authors cautioned that the study design was observational and retrospective, which limits causal inference. The cohort was predominantly male, which may affect generalizability to broader populations, they noted, although veterans represent a group at comparatively higher baseline risk for skin cancer.

In an accompanying review, Dr. Sarah Arron, who leads a high‑risk skin cancer programme at the University of California, said the expanding evidence base supports routine nicotinamide as secondary prevention for patients with skin cancer and that earlier initiation appears to strengthen the effect. Still, both the review and the study team called for randomized clinical trials to better define optimal dosing, duration and the extent of benefit across diverse populations.

Skin cancer incidence has risen in recent years. Cancer Research UK reported a record high in new skin cancer diagnoses last year and estimates that melanoma cases could increase substantially by 2040. Most non‑melanoma skin cancers, including SCC and basal cell carcinoma (BCC), are linked to ultraviolet radiation from the sun and tanning beds and are usually treatable when detected early.

Squamous cell carcinoma is the second most common form of skin cancer and, while often highly treatable at an early stage, can spread and become more difficult to manage if not diagnosed and treated promptly. Melanoma, the deadliest form, is less common but more likely to metastasize; survival rates decline sharply with advanced stage.

Public health guidance continues to emphasize sun‑safety measures as primary prevention: limiting sun exposure during peak UV hours, wearing protective clothing and hats, using broad‑spectrum sunscreen with adequate SPF, and avoiding sunbeds. Clinicians also advise patients to report new or changing moles and growths; standard checks for melanoma include assessing asymmetry, border irregularity, color variation, diameter and evolving lesions.

Researchers noted the study’s limitations, including its retrospective design and the potential for unmeasured confounding. They said any observed association should prompt further prospective investigation rather than immediate changes to clinical practice for primary prevention. The authors recommended randomized trials to establish whether nicotinamide can be recommended routinely, to determine which patient groups would benefit most, and to clarify safety and dosing over longer periods.

The study adds to a growing set of observational and interventional data suggesting a protective role for nicotinamide in secondary prevention of non‑melanoma skin cancers, particularly for patients with prior lesions, but does not replace established prevention strategies or individualized clinical care. Patients concerned about skin cancer risk are advised to consult their healthcare provider before starting supplements.