Nicotinamide (Vitamin B3) to Prevent Repeat Skin Cancers: What the Trials Show
SkinArticleSome dermatologists suggest an over-the-counter form of vitamin B3 for people who've had several nonmelanoma skin cancers. In a year-long trial it lowered new skin cancers by 23%, but the benefit faded after stopping, and it didn't help organ-transplant recipients. A large veterans study suggests starting after a first skin cancer may matter most.
In this article
Basal cell and squamous cell skin cancers are common and caused mainly by sun exposure.1 If you’ve had more than one, your dermatologist may mention nicotinamide, a form of vitamin B3 sold over the counter.1 Here’s what the research shows.
The main trial (2015)
In Australia, 386 people who’d had at least two nonmelanoma skin cancers in the past five years took 500 mg of nicotinamide twice a day or a placebo for a year.1
- 23% fewer new skin cancers overall1
- About 20% fewer basal cell and 30% fewer squamous cell cancers1
- Fewer precancerous rough spots (actinic keratoses), 13% fewer at 12 months1
- Side effects similar to placebo1
- No lasting benefit after stopping1
Transplant recipients (2023)
In people on anti-rejection drugs after an organ transplant, a similar trial found no reduction in skin cancers.2 That trial stopped early because of slow enrollment.2
A large veterans study (2025)
Using health records from more than 12,000 veterans who took nicotinamide, researchers found a 14% lower risk of another skin cancer overall.3 When it was started after a first skin cancer, the risk was 54% lower; the benefit shrank when started later.3 This was an observational study, not a randomized trial, and only 2% of the people were women.3
What this means for you
- It’s for people at higher risk, such as those who’ve already had skin cancer, not a replacement for sun protection or skin checks.
- It likely works only while you take it.1
- Ask your dermatologist whether your history fits the people studied.
- Read labels carefully. The trials used nicotinamide, 500 mg twice daily.1
Our guides to skin checks after 50, actinic keratosis treatments, Mohs surgery, sunscreen pills and hydrochlorothiazide and skin cancer cover related decisions.
Try: “I’ve had two basal cell cancers in three years. Would nicotinamide make sense for me, and is it safe with my other medicines?”
Skin, Head to Toe includes a short-shelf planner and a 12-week SkinLog. Use them to track new spots and any supplement you start. See the book.
This article is for general educational purposes only and is not medical advice. It isn't a substitute for diagnosis or treatment from a qualified healthcare professional who knows your health history. Please talk with your dermatologist or pharmacist before starting a supplement, especially if you have liver disease or take several medicines. A new, growing, bleeding or nonhealing spot should be checked promptly. If you think you may be having a medical emergency, call 911 or your local emergency number right away. This article discusses published research. It does not evaluate any particular brand or product. Girl Playbook does not endorse any specific product, test, or provider.
Girl Playbook sells this book. It provides education and worksheets, not individualized medical care.
Sources
The research behind this article, in the order it’s cited. How we source our articles.
- New England Journal of Medicine (abstract via PubMed), 2015A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention (opens in a new tab)abcdefghij
- New England Journal of Medicine (abstract via PubMed), 2023Nicotinamide for Skin-Cancer Chemoprevention in Transplant Recipients (opens in a new tab)ab
- JAMA Dermatology (full text via PubMed Central), 2025Nicotinamide for Skin Cancer Chemoprevention (opens in a new tab)abc
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