What is niacinamide and what does it do for skin?

Niacinamide is a water-soluble form of vitamin B3, also called nicotinamide, that shows up in serums, moisturizers, and toners at typical concentrations of 2 to 10 percent. Cleveland Clinic describes it as one of the most flexible skincare actives available because it is well tolerated by most skin types, including sensitive skin, and works through several distinct mechanisms rather than a single pathway.

The main thing it does is support the skin barrier. Niacinamide is a precursor to nicotinamide adenine dinucleotide, or NAD+, a coenzyme that the cells use for energy and for repair. As skin ages or is exposed to UV and pollution, NAD+ levels drop, and supplementing with niacinamide seems to help skin cells make better use of available energy. Studies summarized by NIH’s ODS fact sheet and Cleveland Clinic show that topical niacinamide can improve the skin’s moisture barrier, reduce transepidermal water loss, and help the barrier hold onto ceramides and other lipids. That is partly why it tends to calm reactive skin and reduce redness in conditions like rosacea when used consistently.

It also helps with oil control and the look of pores. Several randomized trials have found that 2 to 5 percent niacinamide reduces sebum production and improves the appearance of enlarged pores over 8 to 12 weeks of use, according to a review of the literature in PMC. The mechanism is not fully mapped, but it appears to dial down sebaceous gland activity without stripping the surface. Studies on both Japanese and Caucasian skin show a measurable but moderate effect; this is not the same as a prescription retinoid, but it is enough to make a visible difference for many people over several weeks of consistent use. The same review notes modest brightening of dark spots and uneven tone, especially post-inflammatory hyperpigmentation from old acne, because niacinamide interferes with the transfer of pigment from melanocytes to skin cells. That is a different route than a hydroquinone or a vitamin C serum uses, which is why niacinamide pairs well with those actives.

For acne, niacinamide is not a first-line treatment, but it does help with the inflammation and post-acne marks. Some dermatologists use a 4 percent formulation as a supporting player next to benzoyl peroxide or salicylic acid because it lowers irritation. AAD’s general guidance is to layer niacinamide before moisturizer, after cleansing and after any watery toners, and to avoid mixing it directly with pure vitamin C in the same routine if you have reactive skin, since the combination can occasionally sting. It can be used morning or night; many people use it twice daily.

A good starting product is a 5 percent serum applied to clean skin before moisturizer, with a thin layer of sunscreen on top during the day. If you are also using a retinoid, niacinamide in the morning and retinoid at night is a common split because each does a different job without competing. A small niacinamide serum is one of the lower-cost ways to start. Because niacinamide does not usually cause sun sensitivity the way retinoids or alpha-hydroxy acids do, it is comfortable to use year-round.

If you are pregnant or breastfeeding, niacinamide is generally considered safe because it is a vitamin derivative and does not carry the same restrictions as retinoids. Patch testing is still wise; some people react to it, especially at 10 percent concentrations, and a small daily rash or irritation is a reason to back off. People with very oily skin often see the strongest oil-control effect, while people with dry skin notice the most barrier benefit over several weeks of consistent use. For the bigger picture on layering, see the skincare order guide and the skin barrier explainer.