If you’ve had two or more nonmelanoma skin cancers (such as basal cell carcinoma or squamous cell carcinoma) in the past five years, ask your dermatologist about the advisability of taking a dietary supplement containing nicotinamide (also called niacinamide), a form of niacin (vitamin B3). It may help prevent skin cancer by repairing DNA damage caused by ultraviolet (UV) rays and by reducing UV-related inflammation and suppression of immunity, according to a recent review paper in Experimental Dermatology.
The best evidence for the efficacy of high-dose nicotinamide comes from a well-designed Australian clinical trial in the New England Journal of Medicine in 2015. In it, 386 adults (average age 66) who had at least two nonmelanoma skin cancers in the past five years took either nicotinamide (500 milligrams, twice a day, which is 67 times the daily RDA for niacin) or placebo tablets for a year. The nicotinamide group had 20 percent fewer basal cell carcinomas, 30 percent fewer squamous cell carcinomas, and13 percent fewer actinic keratoses (precancerous lesions) than the placebo group.
There was no benefit during the six months after the nicotinamide was discontinued. No adverse effects were reported. Unlike nicotinic acid, another form of niacin, nicotinamide does not improve blood cholesterol numbers, nor does it cause flushing. Though nicotinamide is sold without a prescription, at such high doses it is more like a drug than a supplement.
Since cancer can take many years to develop, longer-term studies are needed. If you take nicotinamide, don’t let it give you a false sense of security: It won’t protect against all sun damage, so it is still essential to limit sun exposure and use sunscreen.
This article first appeared in the UC Berkeley Wellness Letter.
Also see How to Perform a Skin Exam.