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Niacinamide for UV Protection (Internal Photoprotection)

A

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.

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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 Statistics





            


    

        
5

        
Studies

    

    

        
686

        
Participants

    

    

        
            
            ↑
            
        
        
Positive

    

    

        A

        
Grade

    




        


        
        

        
        
        

            

  
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
                

                
            

            

            

            
            

                Best taken: With meals; can be split into 2-3 doses
            

            
        

        

        
        
        

            

  
Safety & Side Effects





            

                
                

                    
Reported Side Effects

                    
    
                        
                        
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                            Generally well-tolerated (no flushing unlike niacin)
                        
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                            Mild gastrointestinal discomfort at high doses
                        
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                            Rare hepatotoxicity at very high doses (> 3,000 mg/day)
                        
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Known Interactions

                    
    
                        
                        
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                            ●
                            Anticonvulsants (carbamazepine — may increase niacinamide levels)
                        
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                            Hepatotoxic drugs (potential additive liver effect at high doses)
                        
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                            Isoniazid (competes for NAD+ pathways)
                        
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                        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)?
            
        
        

            Based on 5 studies with 686 participants, there is strong evidence from multiple clinical trials that Niacinamide may support UV Protection (Internal Photoprotection) management. Our evidence grade is A (Strong Evidence).
        

    

    
    

        
            How much Niacinamide should I take for UV Protection (Internal Photoprotection)?
            
        
        

            Studies have used various dosages. A commonly studied range is 14-16 mg/day NE (RDA). Always consult your healthcare provider before starting any supplement regimen.
        

    

    
    

        
            Are there side effects of Niacinamide?
            
        
        

            Reported side effects may include Generally well-tolerated (no flushing unlike niacin), Mild gastrointestinal discomfort at high doses, Rare hepatotoxicity at very high doses (> 3,000 mg/day). Most side effects are mild and dose-dependent. Consult your doctor if you experience any adverse reactions.
        

    

    
    

        
            How strong is the evidence for Niacinamide and UV Protection (Internal Photoprotection)?
            
        
        

            We rate the evidence as Grade A (Strong Evidence). This rating is based on 5 peer-reviewed studies with 686 total participants. The overall direction of effect is positive.
        

    

    




        

        

        
        
        

            

  
Related Evidence





            

                
                
                

                
                

                    
Niacinamide for other conditions

                    

                        
                        
                            Acne
                            A

                        
                        
                    

                

                
            

        

        

    


    
    












    

        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.