Vitamin B3 pill shows promise in preventing skin cancer, large VA study suggests.
A common over-the-counter form of vitamin B3, nicotinamide, also known as niacinamide, may help prevent certain skin cancers, according to new analyses published in JAMA Dermatology. In the largest dataset of its kind, researchers examined health records from 33,822 U.S. veterans and found that those taking nicotinamide (500 mg twice daily for more than 30 days) had fewer new skin cancers than comparable patients who did not take the supplement.
“Nicotinamide, a simple vitamin B3 derivative, is showing real promise as a practical tool for skin cancer prevention,” said Dr. Yousuf Mohammed, Senior Research Fellow and research leader at the Frazer Institute, University of Queensland. “In this large Veterans Affairs retrospective study of more than 33,000 patients, those prescribed oral nicotinamide (500 mg twice daily) had a 14% overall reduction in new skin cancers compared with those who did not take it.”
What is nicotinamide?
Nicotinamide is a non-flushing form of vitamin B3 (distinct from niacin). Biologically, it serves as a precursor to NAD⁺, a cofactor involved in cellular energy production and DNA repair. In skin, prior laboratory and clinical research suggests nicotinamide can bolster DNA repair after ultraviolet (UV) exposure and temper UV-induced immunosuppression, mechanisms thought to underlie its potential in skin-cancer chemoprevention.
“For clinicians, the appeal of nicotinamide lies in its accessibility, safety, and tolerability,” Dr. Mohammed noted. “Unlike systemic retinoids or invasive field therapies, nicotinamide is inexpensive, over-the-counter, and free from significant side effects.”
How the research was conducted
The new findings come from retrospective cohort analyses of U.S. Veterans Affairs (VA) electronic health records spanning October 1999 through December 2024. Among 33,822 veterans, 12,287 were exposed to nicotinamide at 500 mg twice daily (for >30 days), and 21,479 were unexposed.
The teams used propensity score matching to account for differences that could influence skin-cancer risk—including prior skin-cancer history (number and timing), age, sex, race, use of retinoids (acitretin), topical field therapies, and histories of chronic lymphocytic leukemia or solid organ transplantation. Stratified Cox models then estimated how nicotinamide use related to time until the next skin cancer.
Importantly, the analyses examined outcomes across three common types of skin cancer and stratified results by patients’ history, particularly whether nicotinamide was started after a first, second, or later skin cancer.
What the studies found
- Overall risk reduction: Across the matched cohort, nicotinamide use was associated with a 14% reduction in the risk of developing a new skin cancer.
- Timing matters: Starting nicotinamide after a first skin cancer was linked to the largest benefit—about 54% lower risk of another skin cancer. The protective effect declined among patients who had already experienced multiple skin cancers before starting nicotinamide.
- By cancer type: Risk reduction was observed across basal cell carcinoma and cutaneous squamous cell carcinoma (cSCC), with the greatest effect in cSCC.
- Transplant recipients: Among solid organ transplant recipients, who face high skin-cancer risk due to immune-suppressing medications, no overall significant risk reduction was seen. However, earlier use showed signs of benefit in lowering cSCC incidence.
“The greatest impact was seen in squamous cell carcinoma, where risk dropped by more than 20%,” said Dr. Mohammed. “Even more striking, patients who began nicotinamide after their very first skin cancer had risk reductions of nearly 50%. These findings highlight that timing matters; starting earlier may be the key to stronger protection.”
The findings suggest that over-the-counter nicotinamide (500 mg twice daily) is a low-cost, generally well-tolerated adjunct that can modestly reduce new skin cancers; however, it is not a substitute for sun protection or routine dermatologic surveillance.
Because these analyses are retrospective and drawn largely from older, predominantly male, White veterans, definitive estimates of benefit and broader generalizability will require prospective, randomized trials and focused work in high-risk groups such as solid organ transplant recipients.
References: “Nicotinamide for Skin Cancer Chemoprevention” by Kimberly F. Breglio, Katlyn M. Knox, Jonathan Hwang, Rachel Weiss, Kyle Maas, Siwei Zhang, Lydia Yao, Chris Madden, Yaomin Xu, Rebecca I. Hartman and Lee Wheless, 17 September 2025, JAMA Dermatology.
DOI: 10.1001/jamadermatol.2025.3238
“Nicotinamide for Skin Cancer Chemoprevention” by Sarah T. Arron, 17 September 2025, JAMA Dermatology.
DOI: 10.1001/jamadermatol.2025.3237
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