Porecelain

Flawless skin starts with the fine print.

Niacinamide

Niacinamide rates Clear, but the rating is a judgement rather than a reading: we identified no comedogenicity assay of niacinamide in any of the numeric papers we hold, and we could trace no primary assay behind the 0 that ingredient checkers print. What it has instead is human trial data pointing the reassuring way — 4% nicotinamide gel has been tested as a treatment for inflammatory acne rather than suspected of causing it. Those trials counted papules and pustules, not comedones, so they reassure without answering the question the word "comedogenic" asks.

Clear Low confidence No legacy score. It does not appear in the assay corpus we searched.

No comedogenicity assay we can find, in either direction. The 0 on the charts is not a measurement.

What it is

Niacinamide is the amide form of vitamin B3, and it appears under a second accepted name, nicotinamide. Its formula is C6H6N2O and its molecular weight is about 122 g/mol — a small, water-soluble crystalline compound. The Cosmetic Ingredient Review's 2005 safety assessment describes niacinamide and niacin as functioning in cosmetics primarily as hair and skin conditioning agents. On a label it is simply Niacinamide. Four near neighbours share the name and are not this material: niacin (nicotinic acid, the free acid), nicotinamide riboside, nicotinamide mononucleotide, and any finished product formulated with niacinamide in it. Nothing on this page transfers between them. The water-solubility is worth flagging and worth not over-reading. Almost everything in the comedogenicity literature is a lipid — an oil, a wax, a fatty acid or one of their esters — and niacinamide is not that kind of substance. That is a plausible reason it never became a test article in the rabbit-ear tables we hold; it is not a result, and it is not a reason to write a zero.

Why we rate it Clear

We rate niacinamide Clear at Low confidence. Clear here is an editorial risk classification, not a measured pass: it records that we found no adverse comedogenic signal and some reassuring human data, and the Low records that the direct measurement is missing entirely. Start with what is absent, because it is most of the story. We identified no comedogenicity assay of niacinamide in the numeric papers we hold. Fulton's 1989 rabbit-ear table, the source of most of the comedogenic numbers now in circulation, has no niacinamide, nicotinamide or vitamin B3 row; we read its 220 rows off a 400dpi render. It does carry a "Vitamins and herbs" section, and on Fulton's 0-5 scale that section prints vitamin A palmitate at 1-3*, tocopherol at 0-3*, tocopheryl acetate at 0, ascorbyl palmitate at 2, an "A & D additive" at 2 and panthenol at 0 — the asterisks being Fulton's "results depend on source of raw material." Niacinamide is in none of it. Panthenol is the row worth naming, because it is a water-soluble B-vitamin derivative that Fulton did put on a rabbit's ear, which means the gap where niacinamide should be is not explained by a rule that water-soluble vitamins were out of scope. Fulton, Pay and Fulton's 1984 paper — a separate rabbit-ear study on its own 0-5 scale, whose key differs from the 1989 one — has no niacinamide row either, and we have now read its Table I in full rather than through a list quoting it. Morris and Kwan's 1983 assay, an independent laboratory on the same 0-5 scale, tested 32 materials: seven lanolins, nine vegetable oils, eleven esters and five surfactants. Niacinamide is not among them. Nguyen, Dang and Maibach's 2007 rabbit-ear study, on a 0-4 scale, names its test materials in its abstract and niacinamide is not one of them. Our own index of the legacy corpus files niacinamide under never tested — which records that no document in that corpus assigns it a score, and is a statement about the corpus rather than about the literature — and acne.org, which catalogues eleven published comedogenicity studies between 1972 and 2009, gives it no entry we could find in any of them. That is why our legacy score field is blank rather than zero. Consumer comedogenic checkers do print a 0 for niacinamide — one such scale page lists it under "Rating 0 - Non Comedogenic" — and we could not trace that number to any primary assay. We are not going to say who entered it or why, because we do not know; the honest statement is narrower and stronger. There is no measurement behind it that we can find, and a 0 sitting in the same column as coconut butter's measured 4 invites a reader to treat an untested ingredient as a tested and cleared one. Untested is not the same as safe. What niacinamide has, and most of the other entries on that untested list do not, is controlled human data. Shalita and colleagues (1995) randomly assigned 76 patients with moderate inflammatory acne to 4% nicotinamide gel (n=38) or 1% clindamycin gel (n=38) twice daily for eight weeks, double-blind; 82% of the nicotinamide arm and 68% of the clindamycin arm were rated improved on a Physician's Global Evaluation, a difference that was not significant (P = 0.19). Khodaeiani and colleagues (2013) ran the same comparison in 80 patients, 40 per arm, scoring Cook's acne grade at baseline, four weeks and eight weeks; both gels reduced the grade substantially and neither beat the other overall. These are not comedogenicity assays and we are not treating them as one. They are weeks of a fairly high dose of niacinamide, in a vehicle, on the exact population that reacts worst to a pore-clogger, with acne improving rather than worsening. Clear rests on those two things: an absence we looked hard for and did not fill, and human use that ran the reassuring way on a different endpoint. Neither is a comedone count. That is also why the confidence is Low.

What the evidence doesn’t tell you

This rating is built almost entirely on absence of evidence, which is a weaker thing than evidence of absence. We identified no rabbit-ear assay of niacinamide, no human comedone-induction study, no cyanoacrylate follicular biopsy — in either direction. An absence of findings and an absence of looking produce the same silence, and here it appears to be the second. Nor can we go further than that: an audit can establish that no assay turned up in the papers we hold and the searches we ran, and it cannot establish that none was ever run anywhere. Clear is the least-wrong call available, not a clean bill of health, and if the assay were run tomorrow we would have no standing to be surprised by the result whichever way it fell. The human trials are the strongest reassuring evidence on this page and they measured the wrong endpoint for this exact question. Shalita and Khodaeiani studied inflammatory acne — papules and pustules — and scored global improvement and acne grade. "Comedogenic" refers to comedones, the non-inflammatory plugs, and neither trial counted comedone induction. Niacinamide has anti-inflammatory activity — it is the rationale Shalita's paper gives for testing it at all — which is a plausible reason it helped inflammatory acne; a material could in principle calm inflammation and still, on a different measure, plug a follicle. We have no data on the second measure. Both trials also tested finished gels at 4%, not the isolated ingredient, and a result about a gel is not a result about a molecule. For the same reason we have deliberately not counted niacinamide's other human literature as evidence here. There are trials of niacinamide on sebum output, on barrier function and on pigmentation, and there are acne studies of multi-ingredient regimens containing it. None of them counts comedones, so none of them answers this question, and importing them would be the same error in a more flattering direction. Safety is not comedogenicity either: the CIR concluded niacinamide is safe as used, with no stinging up to 10%, no irritation in use tests up to 5% and negative guinea-pig sensitisation, but a safety conclusion addresses irritation, sensitisation and toxicity, and we identified no comedogenicity data in that report. Its silence is not proof that the wider literature is silent. The chemical argument noted above — that a small water-soluble molecule is an unlikely pore-clogger — is reasoning, not a result, and reasoning of exactly that shape is how unsourced zeros get into ingredient columns. We lean on it lightly and not at all as proof. Finally, we have no dose-response information of any kind: there is no comedogenic number to attach to any concentration, and where niacinamide sits on an ingredient list tells a reader nothing. Beyond this ingredient, a 2025 review of the field reports that no standardised comedogenicity test exists and that "non-comedogenic" is an unregulated label.

Where you’ll see it

On a label it appears as Niacinamide. We have no current use survey and we are not going to guess at one. The figures we can cite are dated and should be read as dated: the CIR's 2005 assessment recorded niacinamide in around thirty cosmetic formulations — shampoos, hair tonics, skin moisturisers and cleansing products — at concentrations from 0.0001% in night preparations to 3% in body and hand creams, lotions, powders and sprays. That is a use table from 2005, not a description of the current market. The other concentration worth knowing is 4%, which is the strength of the nicotinamide gel used in both acne trials cited here — a trial article above the top of that 2005 cosmetic use range, not a typical cosmetic level. Where in an ingredient list niacinamide appears is not a comedogenicity signal, here or anywhere, and there is no measured number to read off it in any case.

Sources

Each source says what it actually is. Several widely-cited “sources” for comedogenic ratings are republishing the same 1989 assay, and counting them as independent agreement is how a thin evidence base gets made to look thick.

  1. Fulton JE. "Comedogenicity and irritancy of commonly used ingredients in skin care products." J Soc Cosmet Chem 40:321–333 (1989) The rabbit-ear survey most online comedogenic numbers descend from. Method: ingredient diluted to roughly 10% in propylene glycol, applied to the inner ear of New Zealand albino rabbits, three rabbits per assay, follicles scored for keratosis on a 0-5 scale whose own key reads 0-1 "not considered significant," 2-3 "borderline," 4-5 "considered positive." Read here off a 400dpi render of the journal scan rather than through a list quoting it. Cited purely for an absence: its 220 rows contain no niacinamide, nicotinamide or vitamin B3 entry. Its "Vitamins and herbs" section does carry vitamin A palmitate (1-3*), tocopherol (0-3*), tocopheryl acetate (0), ascorbyl palmitate (2), an "A & D additive" (2) and panthenol (0), all on the same 0-5 scale, so the absence is not a section that went untested. Fulton called the survey "not at all definitive." It supports no rating of niacinamide in either direction.
  2. Fulton JE Jr, Pay SR, Fulton JE 3rd. "Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear." J Am Acad Dermatol 10(1):96–105 (1984) An earlier and separate rabbit-ear study from the same lead author: two New Zealand albino rabbits per test, one ear dosed daily for two weeks with the other ear as control, results on a 0-5 scale. Its threshold is not the 1989 threshold — 1984 reads 1-2 as not significant and 3 or above as positive — so its numbers cannot be compared with 1989 numbers without carrying each paper's own key. We have read its Table I in full. Cited here only because it contains no niacinamide or nicotinamide row and therefore adds no score.
  3. Morris WE, Kwan SC. "Use of the rabbit ear model in evaluating the comedogenic potential of cosmetic ingredients." J Soc Cosmet Chem 34:215–225 (1983) An independent laboratory's rabbit ear-canal assay on the same 0-5 scale, three rabbits, materials applied undiluted unless stated, 14 applications, graded microscopically. It predates Fulton 1989 and contradicts it in print on several materials, which is why it is not a republisher of him. Its 32 test materials are seven lanolins, nine vegetable oils, eleven esters and five surfactants. Cited for an absence: niacinamide is not among them.
  4. Nguyen SH, Dang TP, Maibach HI. "Comedogenicity in rabbit: some cosmetic ingredients/vehicles." Cutan Ocul Toxicol 26(4):287–292 (2007) A later rabbit ear-canal study on a 0-4 scale — a third scale, and one that is easy to misread as Fulton's. Its abstract names all fourteen test materials — esters, fatty alcohols, hydrocarbons, one butter and one surfactant (isopropyl palmitate, isopropyl myristate, butyl stearate, isopropyl isostearate, decyl oleate, isostearyl neopentanoate, isocetyl stearate, myristyl myristate, cocoa butter, cetyl alcohol, paraffin, stearyl alcohol, sodium lauryl sulfate, petrolatum). Cited for an absence: niacinamide is not one of them.
  5. acne.org — "What is comedogenicity, and what ingredients are comedogenic? The full story" A republisher of the legacy assays, but a thorough one: it describes eleven published comedogenicity studies from 1972 to 2009 with their methods, and combines them under its own multi-study rule rather than quoting one table. Not an independent measurement of anything. Cited as an index of the literature rather than as evidence — we found no niacinamide entry in it, which is a statement about this document, not about every document.
  6. Cosmetic Ingredient Review Expert Panel. "Final report of the safety assessment of niacinamide and niacin." Int J Toxicol 24(Suppl 5):1–31 (2005) The industry expert-panel SAFETY dossier, in its final published state. Cited for identity and tolerance data only: cosmetic function as hair and skin conditioning agents; use in around thirty formulations at 0.0001% to 3% as of 2005; no stinging up to 10%; no irritation in use tests up to 5%; negative guinea-pig sensitisation at 5% induction and 20% challenge; overall "safe as used." We identified no comedogenicity data in it. A safety conclusion is not evidence of noncomedogenicity, its use table is not a current market survey, and its silence on pores is not evidence that the wider literature is silent.
  7. Shalita AR, Smith JG, Parish LC, Sofman MS, Chalker DK. "Topical nicotinamide compared with clindamycin gel in the treatment of inflammatory acne vulgaris." Int J Dermatol 34(6):434–437 (1995) A randomised double-blind comparative trial: 76 patients with moderate inflammatory acne, 38 to 4% nicotinamide gel and 38 to 1% clindamycin gel, twice daily for eight weeks. Endpoints were a Physician's Global Evaluation, acne lesion counts and an acne severity rating; 82% versus 68% improved (P = 0.19), with papule/pustule reductions of 60% versus 43% (P = 0.168). Characterised precisely because the precision is the point: it is an efficacy trial for INFLAMMATORY acne, its lesion counts are of papules and pustules, and it did not count comedone induction. It is evidence that a 4% nicotinamide gel improved rather than worsened acne-prone facial skin. It is not a comedogenicity measurement, and it tested a gel rather than the isolated ingredient.
  8. Khodaeiani E, Fouladi RF, Amirnia M, Saeidi M, Karimi ER. "Topical 4% nicotinamide vs. 1% clindamycin in moderate inflammatory acne vulgaris." Int J Dermatol 52(8):999–1004 (2013) A second randomised double-blind comparison of the same two gels: 80 patients with moderate inflammatory facial acne, 40 per arm, Cook's acne grade scored at baseline, four weeks and eight weeks. Grades fell in both arms with no significant difference between them; the paper's own finding is that skin type is a significant factor in choosing between the two, nicotinamide faring better on oily skin and clindamycin on non-oily. Cited as corroboration that niacinamide has been studied as a topical acne treatment rather than suspected as a cause, with the same caveat as Shalita: the endpoint is inflammatory acne grade, not comedone formation, and the test article is a finished gel.
  9. Walocko FM, Eber AE, Keri JE, Al-Harbi MA, Nouri K. "The role of nicotinamide in acne treatment." Dermatol Ther 30(5):e12481 (2017) A narrative review, not primary data, of ten clinical studies of nicotinamide in acne found by a PubMed search (Shalita and Khodaeiani included). Cited only to establish that niacinamide's use as an acne therapy is a reviewed position rather than a one-off result, and cited with its own verdict attached, which is not a cheerful one: six of the eight topical studies reduced acne against baseline or matched a standard treatment, and the authors still conclude the effect on acne vulgaris is "unclear ... due to the limited nature of the available literature." A review of treatment trials is not a comedogenicity assay, it counted no comedones, and it is not independent of the trials it summarises.
  10. "Comedogenicity in cosmeceuticals: a review of clinical relevance, regulatory gaps, and future directions." JAAD Reviews (2025) A recent peer-reviewed clinical review of the comedogenicity field from 1972 onward. It is a synthesis of the same legacy literature, not a new measurement, and independent of Fulton only in authorship. Cited for one field-wide caveat: no standardised comedogenicity test exists, and "non-comedogenic" is an unregulated label. It sets the ceiling on how much any comedogenic number, present or absent, can be asked to carry.
  11. Consumer comedogenic checkers and ingredient databases (CosDNA and similar) Aggregators that publish a 0-5 "acne" number per ingredient with no disclosed method, provenance or citation. Niacinamide is listed at 0 on scale pages of this kind. Cited as the artefact being corrected, not as a measurement: we traced no primary assay behind that 0 and we make no claim about where it came from or who entered it. It is not carried as our legacy value.

Others in the same family

Actives behave similarly enough that the evidence for one is often wrongly read across to the others. These are its structural relatives, not a guess. What the evidence says about actives as a family ›

Last reviewed 2026-08-01 · How we decide

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