sirtuins

nad+ + niacin

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+.