Niacinamide is a form of vitamin B3 and one of the most thoroughly studied ingredients in cosmetic skincare. It is also one of the easiest to use, which is why it appears in so many formulas.
What it does
Used regularly, niacinamide helps balance visible oil, refines the look of pores and supports a more even-looking tone. It also supports the skin's moisture barrier, which is why it suits both oily and dry skin.
How much is enough
Most published research uses between 2% and 5%. Higher strengths such as 10% are popular for oily skin, but more is not automatically better. If a strong serum makes your skin flush, step down or use it on alternate days.
How to use it
Apply it after cleansing and before moisturiser, morning or evening. It layers comfortably with hyaluronic acid, vitamin C and sunscreen.
Give it six to eight weeks before judging the results, and patch test first if your skin is easily unsettled.