Vitamins
Niacin (Vitamin B3)
Also known as: Nicotinic acid · Nicotinamide · Niacinamide · Vitamin B3
Dual-use nutrient: at RDA doses it is an essential NAD⁺ precursor. At pharmacological doses (1–3g), prescription niacin raises HDL cholesterol more than any other drug.
Effective Dose
14–500mg / day (purpose-dependent)
per clinical evidence
Evidence Level
Strong
Vitamins
Mechanism
NAD⁺/NADH cofactor for 400+ enzymes; HDL elevation at pharmacological doses
primary action
Best For
Energy metabolism
Cholesterol (HDL), NAD⁺ support, Skin health
This profile is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications.
What Is Niacin (Vitamin B3)?
Niacin exists as nicotinic acid and nicotinamide — both precursors to NAD⁺ (and its phosphate form NADP⁺), which are essential electron carriers in virtually every metabolic pathway. At pharmacological doses, nicotinic acid (not nicotinamide) uniquely raises HDL cholesterol by 20–35% — an effect no other supplement or most drugs can match.
How It Works: The Science
NAD⁺/NADH is the central electron shuttle in glycolysis, the Krebs cycle, and the electron transport chain. At pharmacological doses, nicotinic acid activates GPR109A receptors on adipocytes, inhibiting hormone-sensitive lipase (reducing VLDL secretion) and inhibiting HDL catabolism via ABCA1 upregulation. Niacin also feeds NAD⁺ salvage synthesis.
Primary Mechanism
NAD⁺/NADH cofactor for 400+ enzymes; HDL elevation at pharmacological doses
Evidence-Based Benefits
Dosage Guide
Effective Dose
14–500mg / day (purpose-dependent)
RDA: 14–16mg/day (easily met from food). Cardiovascular use: 1–3g/day nicotinic acid — only under medical supervision. Inositol hexanicotinate ('flush-free niacin') has little pharmacological effect. Nicotinamide (niacinamide): 250–500mg/day for NAD⁺ support without flushing.
Safety Profile & Side Effects
Nicotinic acid causes flushing (prostaglandin-mediated skin vasodilation) — harmless but uncomfortable. High doses (>3g/day) cause hepatotoxicity — monitoring essential at pharmacological doses. Sustained-release niacin has higher hepatotoxicity risk than immediate-release.
Who Should (and Shouldn't) Take It
At RDA doses: everyone (usually met through food). At pharmacological doses: cardiovascular patients under medical supervision. Athletes interested in NAD⁺ support should consider NMN or NR instead of pharmacological niacin.
Frequently Asked Questions
Related Ingredients
Medical Disclaimer
Ingredient profiles are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications. Full disclaimer →