Blog

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

Never miss a breakthrough: Join the SciTechDaily newsletter.

Two of the world’s deadliest mosquito vectors – Aedes aegypti and Anopheles funestus – have evolved, spread, and adapted in ways that complicate global disease control, two studies show. The findings trace the human-linked origins of Ae. aegypti‘s invasive lineage. They also reveal the rapid emergence of insecticide resistance in An. funestus. Collectively, they reveal the urgent need for more tailored and innovative interventions against malaria and dengue. Top of Form”Both [studies] provide important insights into the … the complex role that human activity, both passive and intentional, plays in their movement and adaptations,” writes Tamar Carter in a related Perspective. “These processes have led to complex subspecies genomic diversity that likely translates to functional diversity that is yet to be fully elucidated.” Bottom of Form Mosquito vector-borne diseases represent a major global health challenge, with malaria and dengue each causing hundreds of millions of infections annually, worldwide. The increasing mobility of people and goods has enabled mosquitoes, once confined to relatively narrow regions, to spread widely and adapt to new environments. Although modern genomic analyses could provide insight into the origin, evolution, spread, and control of these vectors, individual mosquito species are unequally represented in studies. Here, in a pair of studies, researchers analyze genomic data from Ae. aegypti and An. funestus mosquitoes to reconstruct their evolutionary and demographic histories.

In one study, Jacob Crawford and colleagues investigated Ae. aegypti – the primary vector of dengue, chikungunya, and Zika. The precise origin of the globally invasive Ae. aegypti has long been debated. Crawford et al. sequenced 1206 genomes from 73 globally distributed populations, using coalescent and phylogenetic analyses to disentangle ancient from recent migration events. According to the findings, after evolving a preference for humans in West Africa, Ae. Aegypti made its way to the Americas during the Atlantic slave trade, with the globally invasive lineage ultimately arising in the Americas. More recently, this invasive lineage has re-entered Africa and interbred with native populations, coinciding with increased dengue outbreaks and the spread of insecticide-resistance mutations.

In another study, Marilou Boddé and colleagues performed a sweeping genomic analysis of An. funestus to investigate how this major malaria vector has adapted, particularly under vector control pressure. Boddé et al. sequenced 701 modern and historic An. Funestus mosquitoes from 16 African countries. The findings revealed a complex population structure – while some populations showed strong geographic structuring, others were genetically connected across wide distances, with distinct lineages emerging in places like North Ghana and South Benin. According to the authors, this diversity suggests that uniform control strategies are unlikely to succeed, emphasizing the need for locally tailored interventions. Moreover, by comparing modern samples with century-old museum specimens, the team showed that insecticide resistance arose both through independent mutations and the spread of resistant lineages. Most insecticide resistant variants found in modern An. Funestus were not found in historical species from as recent as 1967, suggesting rapid emergence. Boddé et al. also discovered promising gene drive targets within An. Funestus, which could enable more effective and strategic vector control efforts.

Malnutrition can cause its own form of diabetes, health experts said Thursday, calling for “type 5 diabetes” to be recognised globally to help fight the disease in countries already struggling with poverty and starvation.

The most common form of diabetes, type 2, can be caused by obesity and occurs when adults become resistant to the hormone insulin. Type 1, mostly diagnosed in childhood, arises when the pancreas does not produce enough insulin.

But diabetes researchers have been tracking another form of the disease, which often appears in people aged under 30. It also affects insulin production but is less severe than type 1.

And rather than being linked to being overweight or obese like type 2, it affects people who are underweight because they do not eat enough.

A paper published in medical journal The Lancet Global Health shows that more than 25 million people suffer from this “type 5 diabetes”, mostly in developing countries.

“We call upon the international diabetes community to recognise this distinct form of the disease,” the authors wrote, reflecting a consensus reached by the International Diabetes Federation earlier this year.

The experts settled on calling this form of diabetes type 5, though types 3 and 4 have not been officially recognised.

Diabetes driven by malnutrition is not a new discovery — in the 1980s and 1990s, the World Health Organization classified a form of “malnutrition-related diabetes”.

But the UN agency abandoned this classification in 1999 due to a lack of agreement among experts about whether undernourishment alone was enough to cause diabetes. Since then, numerous studies in countries including Bangladesh, Ethiopia, India, Indonesia, Nigeria, Uganda, Pakistan and Rwanda have indicated that this is possible.

BANGKOK – The Bangkok Metropolitan Administration (BMA) on Wednesday issued a rabies alert for residents of eight sub-districts in three Bangkok districts following the discovery of a rabid stray dog.

The BMA said the eight sub-districts are within a five-kilometre radius of the location where the rabid dog was found on Chuan Samphan Road in Khok Faed sub-district of Nong Chok district.

The eight sub-districts are:

• Khok Faed, Nong Chok district
• North Khu, Nong Chok
• Lam Phak Chi, Nong Chok
• Nong Chok, Nong Chok
• Saen Saeb, Min Buri district
• Lam Pla Thiew, Lat Krabang district
• Thap Yao, Lat Krabang

The BMA warned residents of the eight sub-districts not to touch stray animals at all, as they could contract the deadly virus.

The BMA also urged residents to contact the Prawet dog shelter at 0 2328 7460 or 0 2328 7355 if they spot dead stray dogs or cats, restless dogs with protruding tongues and excessive salivation that might bite, or animals appearing to have stiffened bodies.

The BMA’s warning follows an order from the Livestock Development Office for Area 1 on Wednesday.

The order declared the Bangkok zones within a five-kilometre radius of the spot where the rabid dog was found as areas for controlling the rabies outbreak from September 17 to October 16.

The order prohibited the transfer of dogs and the movement of dead animals within the area without prior approval from veterinarians or livestock officials.