Niacinamide

Niacinamide, also known as nicotinamide, is the amide form of vitamin B3, one of the water-soluble B vitamins the body needs but stores very little of. In food it appears in meat, fish, mushrooms, nuts and fortified cereals. The version used on skin is made synthetically to a high level of purity, so it behaves the same way from batch to batch rather than varying as a botanical extract can.

It is worth separating it from its close relative niacin, or nicotinic acid. Both sit under the vitamin B3 heading and the body can convert one into the other, but niacin is the form associated with the familiar flushing response. Niacinamide is not, and that is a large part of why it became the version used in cosmetics.

On an ingredients list it appears simply as Niacinamide. Being small and water-soluble, it sits most naturally in watery textures such as serums, essences, toners, gels and light lotions, though it now appears in cleansers, moisturisers and sunscreens too. Cosmetic use typically runs between 2% and 10%, and the higher figures are not automatically better.

Formulators reach for it as a broad supporting active rather than a single-purpose one. It turns up in products aimed at the look of uneven tone, visible pores, dullness, excess surface oil and skin that looks stressed or easily reddened. It is also unusually well tolerated, which is why it is so often the first active recommended to someone whose skin reacts to most things.

A word of caution about how widely it now appears. Niacinamide has become a marketing headline, and it shows up in cleansers, wipes and body washes where it has almost no contact time with skin, and in leave-on products at fractions of a percent. Seeing the name on a bottle is not the same as getting a useful dose of it. If it is one of the reasons you are buying a product, look for a stated percentage or a position reasonably high on the ingredients list, and choose a leave-on format over something you rinse away.

Once it is in the skin, niacinamide is converted into NAD+ and NADP+, two coenzymes that sit at the centre of how cells produce energy and how they handle everyday oxidative stress. NAD+ levels in skin decline with age and after UV exposure, and replenishing the precursor is the most widely accepted explanation for niacinamide’s broad, low-key behaviour. Rather than driving one pathway hard, it appears to help skin cells carry out their ordinary housekeeping properly.

Several strands follow from that. Laboratory and human work indicates it encourages skin cells to produce more of the lipids and structural proteins that hold the surface together, including ceramides and other sphingolipids, free fatty acids, filaggrin and involucrin. In practice, skin tends to hold onto moisture better and looks less dull, tight and flaky. The same barrier effect is why it often makes stronger actives easier to tolerate when used alongside them.

Its effect on the look of pigmentation is indirect. Niacinamide does not appear to block the enzyme that manufactures melanin. Instead it slows the handover of pigment-filled melanosomes from the cells that make them to the surrounding skin cells, so less pigment reaches the visible surface and existing marks gradually look less defined. Its antioxidant reputation follows the same NAD+ and NADP+ route: the reduced forms feed the skin’s own antioxidant enzymes rather than mopping up free radicals directly. Reports of pores looking smaller are thought to relate to improved surface quality and a moderating effect on sebum, rather than to any change in pore size itself.

Niacinamide is one of the easiest actives to slot into an existing routine, and one of the few that genuinely gets along with almost everything.

• Strength: 2–5% suits most people for daily use. Products up to 10% exist, and some people find them less comfortable, so there is no need to start at the top.
• When: morning and night are both fine. Apply to clean skin, before heavier creams and facial oils.
• Order in the routine: after cleansing and any watery toner, before moisturiser and SPF. If you use a vitamin C serum in the morning, either can go first.
• pH: it is most stable around pH 5–7, close to skin’s own, so it does not need the low-pH conditions exfoliating acids require.
• Pairs well with: retinoids, azelaic acid, AHAs, BHAs, peptides, ceramides and hyaluronic acid. It is frequently used specifically to make retinoid nights more comfortable.
• The vitamin C question: the old warning about combining the two traces back to laboratory conditions unlike anything in a bathroom. In practice most people use both, together or at opposite ends of the day, without difficulty.
• If it stings: that usually points to a high percentage or a supporting ingredient in the formula rather than niacinamide itself. Drop to a lower strength or a simpler product before writing it off.
• Patience: comfort and the look of dullness can shift within a few weeks, but tone and dark marks are slow. Give it two to three months of consistent use before deciding.
• Sunscreen: essential if you are using it for the look of uneven tone, or fresh pigment simply replaces what fades.