"High doses (over 500 mg) of specific NAD+ precursors, especially nicotinamide, may increase the risk of adverse effects, including liver strain and potential impacts on vascular health." ...

Nicotinamide riboside (NR ... squamous cell and basal cell carcinoma (the most common type). A study found that 500 mg of NR twice daily in older adults led to increased NAD+ blood levels and ...

She clarified that this is only possible with higher doses and is not typically seen in those taking more typical doses of 500 mg to 1500 mg daily. “Overall, evidence suggests that nicotinamide ...