1. Nicotinamide 500 mg twice daily was studied in veterans with prior skin cancer.
2. Fewer new cancers were seen, mainly squamous cell carcinoma.
3. No overall reduction was found for basal cell carcinoma.
4. Greatest benefit occurred when started following the first cancer.
5. Limitations included an older, White male cohort and reliance on diagnostic codes.

Source: JAMA Dermatology