Niacinamide for UV Protection (Internal Photoprotection)
A Strong Evidence Multiple large clinical trials consistently show significant benefits.The ONTRAC trial (NEJM 2015) found oral nicotinamide 500 mg twice daily reduced new nonmelanoma skin cancers by 23% and actinic keratoses by 11% in high-risk individuals, supporting cellular DNA repair via NAD+ replenishment.
The Bottom Line
The ONTRAC trial (NEJM 2015) found oral nicotinamide 500 mg twice daily reduced new nonmelanoma skin cancers by 23% and actinic keratoses by 11% in high-risk individuals, supporting cellular DNA repair via NAD+ replenishment.
Key Study Findings
Population: Overview of reviews on niacin/nicotinamide adverse effects
Population: High-risk NMSC patients (RCTs)
Population: None
Key Statistics
5
Studies
686
Participants
Positive
Grade
Referenced Papers
Dosage & Usage
mg = milligrams · mcg = micrograms (1,000× smaller) · IU = International Units
Commonly Used Dosages
- general:
- 14-16 mg/day NE (RDA)
- skinhealth:
- 500-1,500 mg/day oral nicotinamide
Upper limit: 35 mg/day for niacin (flushing form); nicotinamide well-tolerated up to 3,000 mg/day
Dosages Studied in Research
| Dosage | Duration | Effect | N |
|---|---|---|---|
| F1: biotin 0.5%, caffeine 2.0%, niacinamide 2.0%; F2: finasteride 0.1%, minoxidil 1.0%, tretinoin 0. | 26 weeks | Positive | -- |
| Vitamin B complex (various B vitamins including niacinamide/NAD+ precursor) | -- | Positive | -- |
| None | -- | Mixed | -- |
| Nicotinamide (vitamin B3) | -- | Positive | -- |
| None | -- | Mixed | -- |
| None | -- | Mixed | -- |
| Niacinamide up to 5%; Niacin up to 0.1% | -- | Mixed | -- |
Best taken: With meals; can be split into 2-3 doses
Safety & Side Effects
Reported Side Effects
- ⚠ Generally well-tolerated (no flushing unlike niacin)
- ⚠ Mild gastrointestinal discomfort at high doses
- ⚠ Rare hepatotoxicity at very high doses (> 3,000 mg/day)
Known Interactions
- ● Anticonvulsants (carbamazepine — may increase niacinamide levels)
- ● Hepatotoxic drugs (potential additive liver effect at high doses)
- ● Isoniazid (competes for NAD+ pathways)
Tolerable upper intake: 35 mg/day for niacin (flushing form); nicotinamide well-tolerated up to 3,000 mg/day
Always consult your healthcare provider before starting any supplement.
Frequently Asked Questions
Does Niacinamide help with UV Protection (Internal Photoprotection)?
How much Niacinamide should I take for UV Protection (Internal Photoprotection)?
Are there side effects of Niacinamide?
How strong is the evidence for Niacinamide and UV Protection (Internal Photoprotection)?
Related Evidence
Other ingredients for UV Protection (Internal Photoprotection)
Niacinamide for other conditions
References
- [1] Su Ling Young et al.. Eye (Lond). 2025. The adverse effects of oral niacin/nicotinamide - an overview of reviews. doi:10.1038/s41433-025-04027-2 PubMed
- [2] Carolina Schettino Kegele et al.. Int J Pharm Compd. 2025. Personalized Compounded Hair Loss Treatments: A Compatibility Assessment of the TrichoConcept™ Vehicle Line. PubMed
- [3] Feiya Du et al.. Int J Vitam Nutr Res. 2025. Advanced Applications of Vitamin B Complex in Plastic and Cosmetic Surgery: Mechanisms and Therapeutic Benefits. doi:10.31083/IJVNR39087 PubMed
- [4] Giulio Tosti et al.. Nutrients. 2023. The Role of Nicotinamide as Chemo-Preventive Agent in NMSCs: A Systematic Review and Meta-Analysis. doi:10.3390/nu16010100 PubMed
- [5] Katherine G Thompson et al.. J Am Acad Dermatol. 2021. Dietary supplements in dermatology: A review of the evidence for zinc, biotin, vitamin D, nicotinamide, and Polypodium. doi:10.1016/j.jaad.2020.04.123 PubMed
- [6] Reed Huber et al.. Skin Therapy Lett. 2020. Nicotinamide: An Update and Review of Safety & Differences from Niacin. PubMed
- [7] Cosmetic Ingredient Review Expert Panel. Int J Toxicol. 2005. Final report of the safety assessment of niacinamide and niacin. doi:10.1080/10915810500434183 PubMed
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products and information on this website are not intended to diagnose, treat, cure, or prevent any disease. The evidence grades presented are based on our analysis of published peer-reviewed research and do not constitute medical advice. Always consult your healthcare provider before starting any supplement regimen.