This trial called the ONTRAC trial was conducted in 386 people in Australia where the risk of skin cancer is the highest in the world. This is where all the original sunscreen trials were conducted because the population risk is so high. In ONTRAC they found that 500mg of nicotinamide twice a day for 12 months reduced the risk of basal-cell and squamous cell skin cancers by 23% versus people receiving placebo. They then looked for benefits for 6 months after stopping nicotinamide and found that the benefits were not evident after stopping therapy. This is called a positive dechallenge and helps support the usefulness of the intervention. Nicotinamide was found to be safe for the liver and did not impact blood pressure or blood cells.
UVA and UVB rays can damage the DNA of skin cells and lead to skin cancer. Sunscreen prevents this damage from occurring and reduces skin cancer through that mechanism. The body has proteins that repair the damage and can prevent skin cancer development but this repair requires vitamin B to produce the energy, called ATP, needed to make these repairs. UVA and UVB rays can also deplete the cells of this ATP and DNA is less likely to be repaired. Nicotinamide is the amide form of vitamin B is has been shown in the lab to enhance skin ATP production.
This study was limited to people at greatest risk and did reduce the risk so in people who have had nonmelanoma skin cancers, it is certainly an inexpensive, safe, and modestly effective thing to try. For those with a big family history, perhaps it is worth it during the summer months when the risk is greatest but this has not been studied and is only an educated guess. For everyone else, the use of sunscreen alone should provide most of the benefits you need and the inconvenience of taking a supplement twice a day is not likely worth it. Also keep in mind, they assured that the supplements in this trial contained 500mg of nicotinamide and there is not the same assurance when you pull a supplement of the shelf in the United States. Products with the USP certification or products certified by outside labs to contain the right amount of the active ingredient are the only ones you should be buying and products that say GMP just means the manufactured it well, not that it contains the active ingredient.
Michael White; Dept. Of Pharmacy Practice, UConn School Of Pharmacy