Niacinamide (vitamin B3)

What it is

Niacinamide, also called nicotinamide, is a form of vitamin B3 found in meat, fish, beans and grains. On the skin it is water-soluble, stable and well tolerated, which is why it appears in serums, moisturisers and sunscreens. It is not the same as niacin (nicotinic acid), the form of the vitamin that causes flushing when taken by mouth. Niacinamide does nothing dramatic quickly; its value is steady, broad and gentle.

What the evidence says

Evidence: moderate. Several randomised trials of 2 to 5% niacinamide show benefits for inflammatory acne, hyperpigmentation, oil production and barrier function, mostly over four to twelve weeks.

Acne: in a double-blind trial of 76 people, 4% niacinamide gel matched 1% clindamycin gel over eight weeks, with 82% of the niacinamide group improved and no risk of antibiotic resistance¹.

Dark spots: niacinamide blocks the hand-over of pigment from pigment cells to the surface skin cells. A 5% moisturiser lightened hyperpigmentation compared with vehicle within four weeks², and in a split-face trial of 27 women with melasma, 4% niacinamide came close to 4% hydroquinone with fewer side effects³. Both trials were in melasma and general hyperpigmentation rather than the marks acne leaves behind, where the evidence is thinner. That makes it a sensible option for melanin-rich skin, where irritation from stronger agents can backfire; see dark spots and hyperpigmentation.

Oil: 2% niacinamide lowered sebum output in a 100-person placebo-controlled trial, with a smaller effect in a second group⁴.

Barrier: it increases the skin's own ceramides and fatty acids and reduces water loss from dry skin⁵.

How people use it

• A serum or moisturiser with 2 to 5% niacinamide, morning and night, on the whole face.
• It layers well with sunscreen, retinoids, benzoyl peroxide and exfoliating acids, so it is a good first active in a simple routine.
• Give it 8 to 12 weeks for acne and oil, and longer for dark marks.

Cautions

• More is not better. The trials used 2 to 5%. Very high strengths have not been shown to work better and are more likely to cause flushing, stinging or redness, particularly on sensitive or rosacea-prone skin.
• Side effects of some kind affected about one in five people using 4% in one trial, though redness, itching or burning specifically affected fewer than one in ten³. Patch test, and start every other day if your skin reacts easily.
• It supports pigment treatment; it does not replace daily sunscreen.
• Pigmentation that is spreading, patchy or not responding should be checked by a professional. See when to see a dermatologist.