Niacin (Vitamin B3)

Tier 2 — promising · Lipids · Skin · Energy metabolism

Two forms, two purposes. Niacinamide reduces precancerous skin spots (Cochrane-confirmed) and supports skin barrier repair. Nicotinic acid raises HDL and lowers triglycerides but causes skin flushing. Avoid sustained-release nicotinic acid — higher liver toxicity risk. Flush-free niacin (inositol hexaniacinate) has no proven lipid benefit.

Dose: Niacinamide: 500–1,000 mg/day for skin. Nicotinic acid: 500–2,000 mg/day for lipids (supervised — liver toxicity risk at high dose).