Beta-carotene for skin cancer prevention
Beta-carotene 50 mg daily vs. Placebo · for Nonmelanoma skin cancer · real-time analysis of 1 studies · updated 2026-05-29
Beta-carotene supplementation does not prevent nonmelanoma skin cancer—a well-powered randomized trial found no effect, as did the Nambour trial.
Efficacy (RCT): Efficacy evidence on clinical outcomes. Effects are risk ratios with number-needed-to-treat where a baseline risk is available. Glossary →
An informative negative: despite an antioxidant rationale, beta-carotene did not prevent skin cancer. Included as a comparator showing that not every supplement works—unlike nicotinamide.
Forest plot—Nonmelanoma skin cancer
Study results—Nonmelanoma skin cancer
| Study | Design | Dose / regimen | Treatment | Control | RR [95% CI] | Improvement | NNT | Weight |
|---|---|---|---|---|---|---|---|---|
| Greenberg 1990 note | DB-RCT | Beta-carotene 50 mg/day | — | — | 1.05 [0.91–1.22] | -5% | — | 100% |
RR < 1 favors treatment for outcomes where lower is better. Rows in gray have a confidence interval crossing 1 (individually inconclusive). “~” marks effects reported as OR/HR and treated as RR-approximations. “excl” = excluded from pooling (e.g. reviews).
Notes & interpretation
- Greenberg 1990—First new nonmelanoma skin cancer; no effect.
Background
The Skin Cancer Prevention Study randomized 1,805 patients with a recent nonmelanoma skin cancer to beta-carotene 50 mg daily or placebo, with 5 years of follow-up. The Nambour trial similarly found no protective effect from beta-carotene.