Topical niacinamide (5%) has shown positive effects on visible skin ageing, skin tone evening, and the skin barrier in multiple studies, with a good safety profile. The evidence is promising but still limited in scale: the strongest study included only 50 participants. For people at elevated risk of skin cancer, the evidence for oral nicotinamide is more robust, but its use warrants medical consultation because the effect disappears once you stop taking it.
Niacinamide is the amide form of vitamin B3 and acts through multiple pathways in the skin: it replenishes NAD+ (a compound that cells need for energy production and the repair of damaged DNA), reduces oxidative stress, and inhibits inflammatory signals. These are plausible explanations for the wide range of applications described in the literature.
On the topic of visible skin ageing, the evidence is concrete. In a double-blind study in which 50 women applied a cream containing 5% niacinamide to one half of their face and a placebo cream to the other half for twelve weeks, the niacinamide side showed statistically significant improvements across multiple measures: fine lines, wrinkles, pigmentation spots, redness, yellowing, and skin elasticity. The study was small, however, and conducted exclusively in white women with sun-damaged skin, so the extent to which the findings apply to everyone is uncertain.
A comprehensive 2024 review concludes that topical niacinamide has clinically supported benefits for a broader range of applications: evening out skin tone, strengthening the skin barrier (relevant for people with dry or sensitive skin), and addressing conditions such as acne, dermatitis, and actinic keratosis (sun damage that can be a precursor to skin cancer). For acne, a caveat applies: a 2020 Cochrane review analysed four studies comparing niacinamide with the antibiotics clindamycin and erythromycin and found no significant differences in dropout rates or side effects, but the studies were small and did not measure patient-reported improvement. The conclusion is therefore that niacinamide for acne likely performs comparably to topical antibiotics, but this is not certain.
Oral nicotinamide (the tablet form) has the strongest evidence, but specifically for people at elevated risk of skin cancer. In a phase 3 trial involving 386 high-risk patients (each with at least two previous non-melanoma skin cancers), 500 mg twice daily for twelve months resulted in 23% fewer new skin cancers and 11 to 20% fewer actinic keratoses compared with placebo. Crucially, the effect disappeared once treatment was stopped. This applies to a specific high-risk group, not to people without a history of skin cancer.
A large observational study of more than 33,000 people (VA database, 2025) found an overall 14% reduction in skin cancer risk with the use of oral nicotinamide, and even a 54% reduction when someone began taking it only after a first skin cancer. In patients who had undergone an organ transplant, there was no significant benefit. Because this is not a randomised study, not all confounding factors can be excluded, even though a statistical correction method was used.
The safety profile of niacinamide is favourable: oral use of up to 3 grams per day is considered safe, and no serious side effects were reported in studies. For daily use on the skin, 5% niacinamide is the most studied concentration, particularly for anti-ageing and skin brightening.
Based on one small randomised split-face study (n=50, PMID 16029679), two reviews (PMID 38722460, PMID 40005371), one Cochrane review on acne (PMID 32352165), one phase 3 RCT for skin cancer (n=386, PMID 26488693), and one large retrospective cohort study (n=33,822, PMID 40960808).