Niacinamide is the most agreeable ingredient in skincare. It stings almost nobody, combines with almost everything, and appears in an enormous number of products. It is also routinely oversold, and the gap between what it is claimed to do and what it has been shown to do is wider than for most ingredients on this site.
This page is mostly about calibration: what the reasonable claims are, at what concentration, and why buying a dedicated niacinamide serum is usually the wrong purchase.
Section 01The claims, sorted
| Claim | Standing | Notes |
|---|---|---|
| Supports barrier function | Reasonable | Associated with increased ceramide production |
| Reduces visible redness | Reasonable, modest | Anti inflammatory effect described in the literature |
| Reduces sebum production | Mixed | Some studies show it, effect size varies |
| Reduces the appearance of pigmentation | Reasonable, modest | Interferes with pigment transfer |
| Reduces pore size | Weak | Appearance may change, structure does not |
| Treats acne | Not established | Not a substitute for a first line acne treatment |
| Reverses ageing | Not established | Retinoid territory, not niacinamide territory |
Sorted properly, niacinamide is a supporting ingredient with two or three reasonable claims at a modest effect size. That is a legitimate thing for an ingredient to be. The problem is that it is frequently sold as though it were the fourth item on this list from the top rather than the second from the bottom.
Section 02Concentration, and the ten per cent problem
The studied range for the effects with the best support is broadly two to five per cent. Products at ten per cent and above became popular because a higher number reads as better value, and there is no good evidence that the additional five per cent produces additional benefit. There is reasonable observational evidence that it produces additional flushing and irritation in a subset of users.
Section 03How to use it
The best way to use niacinamide is not to use it as a step at all. It is stable, water soluble, pH tolerant and cheap, which means it is easy to formulate into a moisturiser. A moisturiser containing four per cent niacinamide gives you the ingredient without adding a step, a bottle or a decision.
If you do use a separate serum
Total 01:15- 01
Apply after cleansing, before moisturiser00:15
It is water soluble and thin, so it belongs early in the sequence. Two or three drops for the face.
- 02
Wait sixty seconds01:00
Then moisturiser. That is the whole protocol. Niacinamide requires no ramp, no recovery nights and no frequency schedule, which is genuinely unusual.
- 03
Use it morning, night or bothEither
It is not photolabile and it does not increase photosensitivity. Time of day is a convenience decision.
Section 04Two persistent claims worth addressing
- That it cannot be used with vitamin C. This originates in laboratory work conducted at temperatures and conditions that do not resemble a face, where niacinamide and ascorbic acid can interact to form nicotinic acid, which causes flushing. In normal use the combination is well tolerated and extremely common. Use both if you want to.
- That it shrinks pores. Pore diameter is largely determined by structure and by sebaceous gland size. What changes with niacinamide, if anything, is the appearance, largely through reduced sebum and reduced local inflammation. That is worth having and it is not the same claim.
You get flushing after applying a high percentage niacinamide product
Reduce to a four or five per cent product. Flushing at high concentration is reported often enough to be worth taking seriously as a dose effect.
You want to reduce oiliness
Niacinamide is a reasonable component but not a solution. Over cleansing is the more common cause of rebound oiliness, and the fix is upstream.
You want to reduce redness
Modest effect. If the redness is persistent, has visible vessels or comes with flushing, that needs a diagnosis before it needs a serum.
You have acne
Use a first line treatment. Niacinamide may support the barrier while you use something that irritates, which is a genuine supporting role, but it is not the treatment.
You are buying your first four products
Do not buy this one. Buy a moisturiser that happens to contain it, and spend the difference on sunscreen.
Section 05Assessment criteria
- Concentration stated and within four to five per centHigher numbers are a marketing signal rather than a performance one, and are associated with more reported flushing.
- Preferably delivered inside a moisturiserFewer steps, fewer bottles, same ingredient. A separate serum adds a decision without adding an effect.
- Not combined with an exfoliating acidThe reason to choose niacinamide is tolerance. A combination product with glycolic acid removes that.
- No claims that belong to other ingredientsA niacinamide product claiming to reverse wrinkles or clear acne is describing a retinoid or a benzoyl peroxide. Treat the claim as information about the seller.
- Fragrance free if your skin is reactiveStandard criterion across this publication and particularly relevant to an ingredient chosen for its gentleness.
Section 06The verdict
Niacinamide is worth having and not worth prioritising. It belongs in a moisturiser, it costs almost nothing, and it will not do anything you can point to on its own. The value of understanding it properly is mostly negative: it stops you spending on a dedicated serum when the money would do more as a sunscreen, and it stops you attributing a result to the wrong product.
For the products that do produce visible change, see the retinoid ramp and azelaic acid. For the comparative picture, the timeline table sets everything against everything else.