Niacin Interactions

Combining high-dose niacin (1-2 g/day, typically extended-release) with atorvastatin or other statins increases the risk of myopathy and rhabdomyolysis. The HPS2-THRIVE trial documented a fourfold excess of myopathy when extended-release niacin was added to simvastatin-based therapy, and the AIM-HIGH trial showed no cardiovascular benefit from this combination.

Tryptophan is converted in the liver to niacin (vitamin B3) at a ratio of roughly 60 mg tryptophan to 1 mg niacin, so adequate dietary tryptophan reduces the niacin requirement and helps maintain NAD/NADP coenzyme pools. Niacin in turn spares tryptophan for serotonin and melatonin synthesis, supporting mood and sleep.

Niacin (vitamin B3) is the precursor to NAD+ and NADH, the electron carriers that feed into Complex I of the mitochondrial electron transport chain where CoQ10 shuttles those electrons toward ATP synthesis. Together they support different stages of the same energy-producing pathway.

Niacin (nicotinic acid) is a vitamin B3 precursor that the body converts to NAD+ via the Preiss-Handler pathway, so pairing oral niacin with direct NAD+ precursors can support cellular NAD+ pools through complementary biosynthetic routes. In a clinical study of mitochondrial myopathy, 1,000 mg/day niacin meaningfully raised muscle and blood NAD+.