What does niacinamide do for skin?

What is niacinamide?

Niacinamide is vitamin B3, or one of the two forms it comes in. StatPearls, on the NIH’s own bookshelf, describes niacin, also known as vitamin B3, as a water soluble vitamin the body uses to build the NAD and NADP coenzymes almost every cell runs on. Niacinamide is its amide form. Nicotinic acid is the other.

The gap between those two words is where the confusion starts, because nicotinic acid is the one that flushes. StatPearls records that niacin causes vasodilation of small subcutaneous blood vessels, leading to cutaneous flushing. A 2021 review indexed by the NIH puts it in one line: unlike nicotinic acid, nicotinamide does not reduce cholesterol or cause flushing. Your serum holds that second one, and nicotinamide and niacinamide are two names for it.

What does niacinamide do to the skin barrier?

The skin barrier is a wall, and niacinamide works on the mortar. The outermost layer of skin is flat dead cells packed into a matrix of lipids: ceramides, cholesterol and free fatty acids. That matrix holds water in and keeps most of what lands on you out.

Niacinamide raises production of the mortar itself. The 2021 review summarises the laboratory work: in cultured human keratinocytes, nicotinamide could upregulate the synthesis of major components of skin barriers, such as ceramide, other sphingolipid fractions (glucosylceramide and sphingomyelin), free fatty acid, and cholesterol. Not one of the three. All of them.

The same review records the finished product version: a facial moisturizer containing 2% nicotinamide improved skin barriers in patients with rosacea, the population where a leaky barrier is the entire complaint.

Niacinamide therefore behaves unlike the actives it sits beside. An acid or a retinoid buys its result by taking the top of the wall apart, and the tightness that follows is the price. Niacinamide works the other side of that ledger.

What else is niacinamide shown to do?

Niacinamide has four other effects with human trials behind them: less oil, fewer clogged pores, less visible pigment and a modest improvement in fine lines. Those trials are small and ran 8 to 12 weeks, so each result is real and unspectacular.

Oil and clogged pores

A 2021 split face trial ran 5 per cent niacinamide plus 2.5 per cent benzoyl peroxide against benzoyl peroxide alone, for 12 weeks. The niacinamide side showed significant reduction in both the acne lesion count and sebum casual levels from baseline, and beat the control on blackheads and whiteheads. On inflamed spots it did not, and the authors say so: the reduction in inflammatory lesions was not significantly different between the two groups. Sebum fell faster on the niacinamide side. Benzoyl peroxide is the other half of that pairing, and our post on getting rid of a pimple overnight covers what it does on its own.

Redness

Redness has flattering headlines and mixed data. The 2021 review reports a trial in which pretreatment with 5% nicotinamide reduced erythema that was induced by UV radiation. The acne trial is the counterweight: post acne redness fell on both sides of the face and the difference was not significant.

Dark spots

Pigment has the clearest mechanism. Niacinamide does not switch melanin production off. The review notes that it slowed the melanosome transfer from melanocytes to keratinocytes, the handover step where pigment reaches the cells you see. In the trial behind that, eighteen Japanese women with multiple types of brown hyperpigmentation used a 5 per cent moisturiser on half the face for 8 weeks.

Fine lines

Fine lines move least. Fifty women applied a 5 per cent product to half the face for 12 weeks, and the review summarises the result as improved fine lines/wrinkles, hyperpigmentation spots, texture, red blotchiness, and skin yellowing (sallowness) compared to the control. All appearance measures, on a moisturiser base. Real, and not a retinoid.

What percentage of niacinamide should you look for?

Niacinamide products and niacinamide trials agree on 4 to 5 per cent. The 2021 review states it directly: in cosmetics, nicotinamide is mainly formulated at a concentration of 4 to 5%. That is the strength most of the trials above used.

Two per cent is not a token dose: the rosacea moisturiser above was a 2 per cent product. In the other direction, the review reports that when 10% nicotinamide was applied to the skin, human subjects did not feel stinging sensation or flushing, and that irritation did not appear in a 21 day cumulative test at 5 per cent. So a 10 per cent serum is not a hazard. It is past the point the human evidence is about. Buying a bigger number is buying past the data.

Can you use niacinamide with vitamin C?

Niacinamide and vitamin C can be used together, and the reason they supposedly cannot rests on a molecule that is not in your serum. The claim is that mixing them turns niacinamide into nicotinic acid and flushes your face. Nicotinic acid is indeed the form that flushes. Nicotinamide is not.

The conversion has now been measured rather than argued about. A 2026 study followed niacinamide, which it shortens to NIA, across human skin and reported that microbial conversion of NIA to nicotinic acid was negligible within the first 24 h, becoming detectable only in much longer experiments.

One real caveat survives, and it is about acidity rather than cancellation. The same study found that neutral donor pH (7.4) increased NIA permeation by roughly twofold compared with acidic pH (5.0), and concludes that donor pH is a critical determinant of how much gets in. Pure vitamin C serums are acidic on purpose. That is a laboratory measure of what crosses skin rather than of anyone getting a worse result, and the practical version is undramatic: one in the morning, one at night. What ferulic acid is doing in a vitamin C serum, and why that serum’s pH is set where it is, is our post on ferulic acid.

What does niacinamide not do?

Niacinamide has no single named target. The review that gathers all of the above says so: currently, there is no convincing evidence that nicotinamide has specific molecular targets for controlling skin aging and pigmentation. It improves several measures at once by a route nobody has pinned down: a fair description and a bad advertising line.

Niacinamide also does not do what its most famous trial did. The strongest result here is a skin cancer one: a review of oral nicotinamide records a phase three trial of 12 months of oral NAM (500 mg twice daily) or placebo, known as the ONTRAC study, and outlined a 23% reduction in the development of NMSCs at 12 months. That was a tablet taken twice a day for a year by people who had already had two skin cancers, and the review excluded articles about topical use. None of it transfers to a serum.

Nor does it replace what dermatologists lead with on pigment. The American Academy of Dermatology’s melasma page starts with applying a broad-spectrum sunscreen (SPF 30 or higher) throughout the day, and the gentler options it names are azelaic acid, kojic acid and vitamin C. Niacinamide is not on that page.

Does niacinamide change if you are pregnant, breastfeeding or have PCOS?

Niacinamide is the rare active whose answer barely moves across the six profiles Truva answers for. Most of this blog exists because it does move: a topical retinoid is a mainstay of keratosis pilaris care and the one thing pregnancy guidance is firmest about. No published body restricts niacinamide for any of the six.

Two rows read differently, and that difference is a gap rather than a warning. Nobody has published a rule, and an absence of one is not a clearance.

If you are pregnant

Pregnancy guidance does not mention niacinamide either way. ACOG lists the over the counter ingredients that can be used during pregnancy and names four, none of them niacinamide. Its list of prescription medicines to avoid names hormonal therapy, isotretinoin, oral tetracyclines and topical retinoids, and niacinamide is not on that one either. ACOG’s instruction for anything unlisted is to contact your obstetrician.

If you are breastfeeding

Breastfeeding has the same gap, and how it was checked is worth showing. The NIH’s Drugs and Lactation Database runs to thousands of substances, and its contents listing goes from Nabumetone to Nystatin without a single entry for niacinamide, nicotinamide or niacin. There is one for nicotine. It is silent because nobody has put anything in it, which is a very different sentence from the ones it writes about retinoids.

One nearby warning should not be read across. StatPearls advises abstaining from breastfeeding during treatment with niacin, which is the other molecule at a pharmacological oral dose for cholesterol.

If you are trying to conceive

Trying to conceive is where a retinoid earns a caution and niacinamide does not. Truva flags a retinoid here because a firm pregnancy instruction gets borrowed forward across the window in which somebody is pregnant before they know it. Niacinamide has none to borrow.

If you are postpartum, or have PCOS, or neither

Postpartum, PCOS and general use return one answer on the same tolerability data. PCOS changes nothing about what may go on your skin, though the oil and acne findings are the relevant ones: NICHD lists increased hair growth, dark patches of skin, acne, insulin resistance, and irregular menstrual bleeding among the possible symptoms, and two of those are things niacinamide has been measured against.

Truva was built to make this split, and here it barely opens. The comparison pages set out why a scanner that never asks your situation cannot tell you which case you have.

When should niacinamide go to a doctor rather than a basket?

Niacinamide that stings, reddens or itches is worth stopping rather than pushing through, because the published irritation testing says most people do not get that. If you are pregnant or breastfeeding, take the whole ingredient list to your obstetrician or midwife rather than the one word: niacinamide is rarely the only active in a bottle.

Key takeaways

• Niacinamide is vitamin B3 in its amide form. Nicotinic acid is the other form and the one that flushes, which is where the scare stories start.
• Its best evidenced effect is the barrier. In cultured skin cells it raised the synthesis of ceramide, free fatty acid and cholesterol, and a 2 per cent moisturiser improved barrier function in rosacea.
• Four other effects have human trials behind them: less oil, fewer blackheads and whiteheads, less visible pigment and modest improvement in fine lines. Most ran 8 to 12 weeks at 5 per cent.
• Cosmetics are mainly formulated at 4 to 5 per cent. Vitamin C can be used alongside it, and the only measured caveat is that niacinamide crosses skin about twice as well from a neutral base.
• No published body restricts topical niacinamide for any of the six profiles. ACOG’s pregnancy list does not name it and the NIH’s lactation database has no entry. Silence rather than a clearance, and still the quietest ingredient on the shelf.

Where this came from

Every health claim on this page links to the body that published it. Nothing here comes from another blog.

Every link above was fetched and confirmed to resolve on 6 September 2026.

Truva summarises published guidance from bodies including ACOG, the FDA, the EU SCCS and the Cosmetic Ingredient Review. It has no access to your medical history and it is not a substitute for your doctor, dermatologist or midwife. This post was written by the Truva team from the sources listed above. It has not been reviewed by a clinician, and nothing in it is a diagnosis or a prescription. If you are pregnant, breastfeeding or being treated for PCOS, take the ingredient list to the person looking after you.