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
strongThe 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
This page is public and indexed on purpose (unlike profiles and drops, which are unlisted) — it’s the citation behind shared ingredient cards, and it should be findable.
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