The study and its comparison
A randomized controlled trial enrolled 386 participants. Its population was adults with at least two nonmelanoma skin cancers in the previous five years. The comparison used nicotinamide 500 mg twice daily versus placebo, with observation over twelve months plus six months after treatment. [1]
The rate of new nonmelanoma skin cancers was 23% lower during treatment, with a 95% confidence interval of 4% to 38%. Basal-cell carcinoma considered separately was not significantly reduced. Benefit was not evident after stopping. [1]
What the finding establishes
This is a relative rate reduction, not a 23-percentage-point reduction in individual risk. Nicotinamide is not interchangeable with nicotinic acid, and the study did not test zinc or topical skincare. NHMRC funded the trial; the result does not replace dermatologic surveillance. Complete funding and conflict details were not independently established. [1]
A hypothetical distinction
Imagine benefit is observed while taking a study preparation but disappears after discontinuation. Long-lasting protection has not been demonstrated.
| Detail | Interpretation |
|---|---|
| Measured outcome | Keep the endpoint specific |
| Study preparation | Not every retail product |
| Remaining uncertainty | Not resolved by a mechanism |
Sources for this article
- A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention.
Source consulted: 2026-09-19. This is a reference resource, not a claim that we conducted the studies or tested a product.