Cetyl Acetate
Cetyl acetate carries a comedogenic 4, and unlike most of the famous numbers, it is genuinely the material's own: its own row in Fulton's 1989 rabbit-ear assay, and the additive Fulton named as the reason acetylated lanolin alcohol scores what it does. One rabbit-ear assay, no second lab, and no human comedogenicity study.
Fulton 1989 prints an exact cetyl acetate row at 4 of 5 - positive on his key, one assay, no replication.
What it is
Cetyl acetate is the acetate ester of cetyl alcohol — cetyl alcohol reacted with acetic acid, its free hydroxyl capped with an acetate group. The Cosmetic Ingredient Review's expert panel assessed it in 2012 as one of a group of alkyl acetates, and describes it as a waxy solid used as a skin-conditioning agent and emollient. That is what a formulator reaches for it for: an emollient in the oil phase. It has a second life that matters more than its own, and it is the reason this page exists. Cetyl acetate is a named component of at least one commercial lanolin derivative sold as acetylated lanolin alcohol. Lubrizol sells that material today, under the name Acetulan, and declares it as "a 100% active, cetyl acetate and acetylated lanolin alcohol" — the acetate is not an impurity in that blend, it is one of the two named components. Where a formula uses that blend, both names are declared on the label. That is a statement about one supplier's product, not about every material sold as acetylated lanolin alcohol: a generic acetylated lanolin alcohol listing does not by itself establish that cetyl acetate is present, or at what level.
Why we rate it Clogging
We rate it Clogging at Low confidence. The confidence is Low because the evidence is a single rabbit-ear assay, and we say so plainly rather than dress it up. The number is real, and it is this material's. Fulton's 1989 survey in the Journal of the Society of Cosmetic Chemists — the source of nearly every comedogenic score in circulation — gives cetyl acetate its own row in Table I, among the esters. Its comedogenicity grade is 4 on his 0 to 5 scale. By Fulton's own published key, "a minimal grade of 0 to 1 is not considered significant," 2 to 3 is "borderline," and "a grade of 4 to 5 is uniformally reproduceable and considered positive." So a 4 is not a borderline 2 or a rounding artefact — it is in the one band Fulton treats as a real finding. And the row sits in the ester section, not the "Oils" section, so his footnote about oils — "results depend on source of raw material" — does not apply to it. There is no asterisk on this row. It is also a reading rather than the ruler: Fulton defined grade 5 by isopropyl myristate, not by this material. The method behind that 4 is worth stating, because it is the whole of the evidence: the ingredient diluted to roughly 10% in propylene glycol, about 1 mL applied to the inner ear of three New Zealand albino rabbits, five days a week for two weeks, the follicles then scored for keratosis under a micrometer. Rabbit ears in 1989. Not human skin, not a finished product. What makes this row unusual is what Fulton did with it. He did not just score cetyl acetate; he pointed at it. Writing about the lanolin derivatives on page 326, he says: "The acetylated lanolin alcohols are both comedogenic and irritating, not because of the acetylated lanolin but because of the cetyl acetate additive." Elsewhere in the same table, acetylated lanolin alcohol — a different molecule, and not to be confused with plain acetylated lanolin, which the 1989 table scores 0 — carries the same comedogenicity grade of 4. So the high number in that corner of the lanolin family is, by the account of the man who produced it, the acetate's doing. Cetyl acetate is not an incidental ester on a list. It is the ingredient the author of the number named. Two cautions on how far that carries, because it is easy to over-read. First: Fulton's own explanation means cetyl acetate and the alcohol are not two independent confirmations of each other — his point is that one component is carrying the other, so counting both as separate measurements would be counting the same effect twice. Second: what Fulton reports is an attribution, in prose, not a controlled experiment. He ran no comparison of the blend with and without the acetate, and reports no supplier, purity or certificate of analysis for either row. A matching grade is consistent with his explanation; it does not demonstrate it. So the honest statement is narrower than "cetyl acetate causes the lanolin problem": Fulton scored a material he labelled cetyl acetate a 4, and he believed that same acetate was responsible for the derivative's grade. The rating rests on the row.
What the evidence doesn’t tell you
Everything here rests on one rabbit-ear study, using three rabbits, in one paper, in 1989. It was tested at roughly 10% in propylene glycol — a single concentration, so there is no dose-response curve. We are not going to tell you that is unrealistically high, either: the CIR's 2012 assessment reports human testing of finished formulations containing about 11.7% and 12.6% cetyl acetate. What that comparison cannot do is close the gap, because the matrix, the exposure and the endpoint were all different, and no comedogenic threshold has been measured for this material at any concentration. One column of Fulton's own table is missing from what we hold. Table I prints comedogenicity and irritancy side by side; the transcription this page is checked against carries the comedogenicity column only, so we quote his prose on the irritation ("both comedogenic and irritating") and print no irritancy number. There is no second reading. We identified no assay of cetyl acetate outside Fulton 1989 anywhere in the legacy corpus we hold: Morris and Kwan's independent 1983 rabbit study, on the same 0 to 5 scale, has no cetyl acetate row at all, and Fulton's own earlier 1984 rabbit paper — which we have now read in full — does not test it either. So unlike an ingredient where two labs happen to agree, this 4 stands or falls on a single assay, and nothing corroborates it. We identified no human comedogenicity study of cetyl acetate. Human data on the material are not absent altogether — the Cosmetic Ingredient Review's assessment of the alkyl acetates draws on human patch testing of finished formulations containing it — but those tests measured irritation and sensitisation, and a safety conclusion is not a comedogenicity result. No document we found measured follicular plugging on human skin for this ingredient, by cyanoacrylate biopsy, comedone count or anything else. Human comedogenicity protocols generally read the upper back rather than the face, and we found no reading of either. A note on the range. Fulton's figure is 4, flat, with no range and no asterisk. Neither of the two 4 to 5 results in the corpus we hold is this material's: both are Morris and Kwan's, from 1983, and they belong to acetylated lanolin alcohol and to isopropyl linoleate. If you meet a 4 to 5 attached to cetyl acetate, we found no assay behind it. And the assay itself is contested. Frank asked in 1982 whether the rabbit ear model, in its then-present state, was "prophetic of acnegenicity" at all; Draelos and DiNardo, in a 2006 "Current Issues and Opinion" piece, tested finished products on human upper backs and found some testing non-comedogenic despite containing ingredients the rabbit assay had scored comedogenic — a finding about formulas rather than a head-to-head validation of the model, but a real caution against reading an ingredient score as a verdict on the product it ends up in; a 2025 review in JAAD Reviews found that no standardised comedogenicity test exists and that "non-comedogenic" is an unregulated label. Those objections apply to this 4 as much as to any other. The difference here — and it is the only reassuring thing on the page — is that they do not touch who the number belongs to: the 4 is genuinely cetyl acetate's. What is unsettled is only whether a 1989 rabbit ear tells you what this ester does on human skin.
Where you’ll see it
On labels it appears as Cetyl Acetate, used as an emollient and skin-conditioning agent. The CIR's 2012 assessment describes human testing of finished formulations containing about 11.7% and 12.6% cetyl acetate, one of them a lipstick — figures from that assessment, not a current market audit, and we have not audited the market ourselves. The place it is most worth recognising is not on its own. If you see "Cetyl Acetate" and "Acetylated Lanolin Alcohol" together on a label, that pairing is the kind of two-component blend Fulton's prose describes, and it is what Lubrizol sells today as Acetulan. That is a statement of what one supplier sells now, not a certificate for what Fulton tested in 1989 — but it is why the two names travel together, and why the ingredient behind a lanolin-derivative score ends up printed a few lines away under its own name.
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.
- Fulton JE. "Comedogenicity and irritancy of commonly used ingredients in skin care products." J Soc Cosmet Chem 40:321-333 (1989) The primary source, and the origin of the number — read off a render of the journal scan, not via a list quoting it. A rabbit-ear assay: the ingredient at roughly 10% in propylene glycol, about 1 mL applied to the inner ear of three New Zealand albino rabbits, five days a week for two weeks, follicular keratosis scored under a micrometer, on a 0 to 5 scale whose own key calls 0 to 1 "not considered significant," 2 to 3 "borderline," and 4 to 5 "considered positive." Table I carries a cetyl acetate row in the ester section at comedogenicity 4, with no asterisk and no range; the table's second column, irritancy, is not in the transcription we check against, so we print no number for it. The paper's body, on page 326, names cetyl acetate as the additive responsible for the acetylated lanolin alcohols being "comedogenic and irritating." It is one assay, by one author, and Fulton himself called his survey "not at all definitive but simply designed to stimulate research."
- 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 primary rabbit-ear assay on the same 0 to 5 scale, six years before Fulton 1989, in a different laboratory — not a republisher of him. Undiluted material unless otherwise stated, three rabbits, 14 applications, microscopic grading. Cited here for what it does NOT contain: its 32 rows include no cetyl acetate, so it offers no corroboration of the 4. It does print a 4 to 5 against acetylated lanolin alcohol — a different molecule — and another against isopropyl linoleate. It also contradicts Fulton in print on other materials, which is why a single agreeing number would not have settled much either.
- Heldreth B, Bergfeld WF, Belsito DV, et al. "Final Report of the Cosmetic Ingredient Review Expert Panel on the Safety Assessment of Methyl Acetate." Int J Toxicol 31(4 Suppl):112S-136S (2012) The published final report of the CIR expert panel's group assessment of the alkyl acetates, which includes cetyl acetate — the peer-reviewed document itself, not a consumer portal summarising it, and not one of CIR's earlier tentative or draft-final packets. Cited for three things only: identity and function, the concentrations of the finished formulations it reports human testing on (about 11.7% and 12.6%), and the panel's conclusion that the group is safe in the present practices of use and concentration. It reports no comedogenicity testing of cetyl acetate; its human data are irritation and sensitisation endpoints. A safety conclusion is not evidence of noncomedogenicity, and we do not use it as one.
- Lubrizol - Acetulan lanolin derivative, technical product page Manufacturer documentation, cited only to establish what one acetylated lanolin alcohol material on the market actually is: Lubrizol describes Acetulan as "a 100% active, cetyl acetate and acetylated lanolin alcohol." It states what Lubrizol sells today. It does not establish that Fulton tested Lubrizol's product, that his 1989 sample had this composition, or that every material sold as acetylated lanolin alcohol contains cetyl acetate. Not a comedogenicity study.
- Frank SB. "Is the rabbit ear model, in its present state, prophetic of acnegenicity?" J Am Acad Dermatol 6(3):373-377 (1982) The earliest peer-reviewed challenge to the assay this page's only number comes from. Cited for a caveat that applies symmetrically: the model's weaknesses undermine an alarming 4 exactly as much as a reassuring 0.
- Draelos ZD, DiNardo JC. "A re-evaluation of the comedogenicity concept." J Am Acad Dermatol 54(3):507-512 (2006) A "Current Issues and Opinion" piece that tested finished products on human upper backs and found products testing non-comedogenic despite containing ingredients the rabbit assay had scored comedogenic. It is not a same-substance rabbit-versus-human validation and we do not present it as one; it is evidence that an isolated ingredient's score does not transfer intact to the formula it ends up in.
- "Comedogenicity in cosmeceuticals - a review of clinical relevance, regulatory gaps, and future directions." JAAD Reviews (2025) A recent peer-reviewed narrative review of the whole field, covering literature from 1972 onward. A synthesis, not new data, and not independent of Fulton in the sense of testing anything — but independent of the consumer lists that republish him. Cited for the field-wide finding that no standardised comedogenicity test exists and that "non-comedogenic" is an unregulated label.
Others in the same family
Esters 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 esters as a family ›
Last reviewed 2026-08-01 · How we decide