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Ni

Niacin (vitamin B3)

Niacin

Nicotinic acid. NOT the same as niacinamide — niacin causes flushing; niacinamide doesn't.

What it does

Niacin and niacinamide are different molecules with different effects despite their close chemical relationship. Niacin is converted to niacinamide in the body, but topically applied niacin causes vasodilation (flushing, warmth, redness) — the same 'niacin flush' people get from oral supplementation. Niacinamide is the cosmetically useful form. The two get confused frequently because INCI lists sometimes use 'niacin' colloquially.

The evidence, graded

expert consensusThe old claim that vitamin C and niacinamide cancel each other out is debunked. Modern formulations are pH-stable and these ingredients are commonly combined safely.Bissett 2005 · Dermatologic Surgery ↗

Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.

Also known as

nicotinic acid

Pairs worth knowing

Niacinamide (Vitamin B3) · works together ↗

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