NiacinamideNicotinamide · Vitamin B3
A vitamin-B3 form used in skincare for barrier support and pigmentation.
Niacinamide, also called nicotinamide, is a form of vitamin B3. It has two quite separate lives: as a topical skincare active, and as an oral nutrient, and the evidence for each does not transfer to the other.
Applied topically it is one of the better studied ingredients in skincare, and unusually well tolerated. Reviews report improvements in barrier function, reduced transepidermal water loss, reduced pigmentation and improvements in the appearance of fine lines and redness, at concentrations commonly used in commercial products.
Its tolerability is part of why it is useful. It irritates far less than retinoids or exfoliating acids, it layers easily, and it is a reasonable option for people whose skin barrier is already struggling.
Taken orally it is a nutrient, and deficiency of vitamin B3 causes pellagra. Its most notable clinical evidence is the ONTRAC trial, in which oral nicotinamide reduced new non-melanoma skin cancers in people with a history of them. That population was high risk, and the result does not translate into a recommendation for the general public.
It is distinct from niacin, the other form of B3, which causes flushing and is used at high doses for lipids. Niacinamide does not cause flushing, and the two should not be treated as interchangeable.
This site does not give doses for supplements, and oral use above ordinary dietary amounts is a conversation for a clinician.
In practice, niacinamide is a sensible, low irritation addition to a skincare routine, and sun protection and a retinoid remain the two with the strongest evidence for photoageing.