Cetyl Palmitate
Cetyl palmitate is rated Clear, and its comedogenic 0 is a real reading rather than a fabricated or borrowed one — but it is a single rabbit-ear score from 1989, with no second laboratory behind it and no human comedogenicity test of the isolated ingredient that we can find, on a material whose ester relatives carry some of the highest numbers in the same survey.
Wax ester thickener; Fulton 1989 alone prints 0 of 5. One lab, once; no second assay we can find.
What it is
Cetyl palmitate is the ester of cetyl alcohol, the sixteen-carbon fatty alcohol, and palmitic acid, the sixteen-carbon saturated fatty acid. Its CAS number is 540-10-3. It is a wax — a solid at room temperature — and it occurs naturally as a major constituent of spermaceti; the cosmetic material is made by esterifying cetyl alcohol with palmitic acid. On a label it is Cetyl Palmitate. A formulator uses it as an emollient and, more often, as a structuring agent: it thickens and stabilises emulsions, firms up the texture of a cream, and opacifies lotions and lotion shampoos. One distinction matters for the rest of this page. Cetyl palmitate is a wax ester — a fatty alcohol joined to a fatty acid — whereas the two esters it is usually filed beside, isopropyl palmitate and ethylhexyl palmitate, join that same palmitic acid to a small or branched alcohol and are light, spreadable liquids. The three share the word "palmitate," which names only the acid half of the molecule. We flag the difference because the comedogenic numbers below diverge sharply across it — not because we can tell you the chemistry is what causes the divergence. It is also worth keeping cetyl palmitate separate from Cetyl Esters, which is a different INCI name for a synthetic wax that is a mixture of fatty-alcohol/fatty-acid esters in the C14–C18 range. Fulton scored a row he called "Cetyl ester NF" at 1 on his 0-to-5 scale, and that row is not this one: a mixed wax and a single defined ester are two test materials, and neither number belongs to the other. Cetyl palmitate is the single, defined ester, and it is the one Fulton scored 0.
Why we rate it Clear
We rate it Clear at Low confidence. The confidence is Low because the entire comedogenic record for this ingredient is one rabbit-ear reading, with nothing behind it and nothing beside it. The number. James Fulton's 1989 survey in the Journal of the Society of Cosmetic Chemists — the source of nearly every comedogenic score in circulation — prints a row for cetyl palmitate, and we read it off a render of the journal scan rather than a list quoting it: comedogenicity grade 0, on a 0-to-5 scale, with no asterisk. On Fulton's own published key, "a minimal grade of 0 to 1 is not considered significant." A 0 is the lowest reading the assay produces. It is worth being exact about what that records. Fulton's earlier 1984 paper spells the bottom of the scale out as "no increase in visible follicular keratosis" — so a 0 is the absence of a visible increase under his scoring procedure, in his animals, at his concentration. It is not a finding that nothing whatever happened in the skin, and it is not a result about another concentration or another commercial grade. Within those bounds, the number is not wrong. It is not borrowed from a neighbouring molecule, and it is not invented on a consumer forum. Fulton names the material by the same generic name the label uses, which is as far as the identity can be traced: he records no supplier, no purity and no batch, so "the exact material" means the exact printed name, not a demonstrably identical lot. What makes the row worth a page is the company it keeps. Cetyl palmitate is an ester, and esters carry some of the highest numbers in Fulton's table — three of the five rows he graded 5 are esters. Isopropyl myristate is one of them, and its 5 is not a measurement at all: Fulton defined the top of his scale as comedones "similar to those induced by the application of our standard 'positive' testing agent, isopropyl myristate." Isopropyl isostearate and myristyl myristate also sit at 5. The palmitates specifically split: Fulton scored isopropyl palmitate 4 and ethylhexyl palmitate 4, and cetyl palmitate 0. Three esters of the same acid, three readings, and the shared word "palmitate" — which is only the acid half of the name — predicts none of them. A reader who has learned that "palmitate" means "pore-clogging" has learned something that is not true of this one. We are not going to tell you why. The tempting move is a mechanism — cetyl palmitate is a large, solid wax and isopropyl palmitate a small penetrating liquid, so surely that explains it — and we have been caught before reaching for exactly that kind of tidy chemistry to prop up a rating. Fulton measured comedones; he did not explain them, and neither can we. The honest statement is narrower: the same assay, run on three esters of palmitic acid, returned 0 for this one and 4 for two others, and we are reporting the readings, not a theory of them. So the rating is Clear, and the evidence under it is a single legacy rabbit-ear 0 with no corroboration. That is a statement about the confidence, not a doubt about the direction.
What the evidence doesn’t tell you
Everything above rests on one rabbit-ear assay in three rabbits. Fulton's method: 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, follicles then scored for keratosis under a micrometer. Three animals, one laboratory, one reading. Fulton called his own survey "not at all definitive but simply designed to stimulate research," and warned that the rabbit ear is more sensitive than human skin. We went looking for a second reading and did not find one. Morris and Kwan's 1983 rabbit-ear assay — an independent laboratory, six years earlier, on the same 0-to-5 scale — scored isopropyl palmitate 3 and octyl palmitate 2-3 across its thirty-two rows, but prints no row for cetyl palmitate. Fulton's own earlier 1984 survey has no cetyl palmitate row either. Beyond those, no numeric paper in the legacy corpus we hold assigns this material a score, and that corpus is not a complete census of the literature — every time we have told ourselves it was closed, it has turned out not to be. What we can say is bounded: the 0 is not two labs agreeing, it is one lab once, and we found nothing that contradicts it either. We identified no human comedogenicity study of isolated cetyl palmitate — no test that put the ingredient on its own on a human face or back and counted comedones. Its general safety in cosmetics is documented: the Cosmetic Ingredient Review's 1982 assessment of the palmitate esters judged cetyl palmitate safe as used, on toxicity, irritation and sensitisation evidence. But safety is not comedogenicity. A material can be non-toxic and non-irritating and still plug a follicle, and that assessment was not measuring pores. Converting a safety conclusion into a comedogenic one is a substitution this site exists to catch, and we are not going to make it here. The assay itself is contested, in a way that cuts toward a 0 as much as away from a 4. Frank asked in 1982 whether the rabbit ear predicts human acnegenicity at all. Draelos and DiNardo, in 2006, tested finished products on human backs and found that isolated ingredient scores did not transfer to the formulas they ended up in. A 2025 review in JAAD Reviews found that no standardised comedogenicity test exists and that the label "non-comedogenic" is unregulated. Those objections weaken a reassuring rabbit score exactly as much as an alarming one. And they leave one thing unestablished that it would be convenient to assume: how much a rabbit-ear 0 predicts about a human face is not known. That the model tends to flag some materials human skin tolerates says something about its false positives; it does not tell you what a negative is worth. So the 0 is a genuinely low result inside the assay, and the assay's negative predictive value for an isolated ingredient on human skin has not been measured. Unproven is not the same as proven.
Where you’ll see it
On a label it appears as Cetyl Palmitate. It is used as a structuring and thickening agent in leave-on emulsions — moisturisers, creams and lotions, sunscreens, and colour cosmetics such as lipsticks and foundations — where it firms the texture, stabilises the emulsion and opacifies the base; it is also used as a plain emollient. The Cosmetic Ingredient Review's 1982 assessment recorded it as a widely used cosmetic ingredient, but that is a use survey from the early 1980s and not a current market measurement. We have not audited its market share, and label position is not a dose, so treat the list above as the categories it suits rather than a measured prevalence. The one thing worth keeping straight is the family. "Cetyl Palmitate," "Isopropyl Palmitate" and "Ethylhexyl Palmitate" read almost alike on an ingredient list and share the same acid, but Fulton scored the first 0 and the other two 4. The shared word does not carry a shared number.
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 of nearly every comedogenic number in circulation, and the only document we hold that assigns cetyl palmitate a comedogenicity score. Read off a render of the journal scan rather than a list quoting it. Method: ingredient at roughly 10% in propylene glycol, 1 mL to the inner ear of three New Zealand albino rabbits, five days a week for two weeks, follicular keratosis scored under a micrometer — three animals, a rabbit ear, not a human face. Its Table I prints "Cetyl palmitate 0" on a 0-to-5 scale, with no asterisk. Fulton's own key: 0 to 1 "not considered significant," 2 to 3 "borderline," 4 to 5 "considered positive." The same table scores isopropyl palmitate 4, ethylhexyl palmitate 4, cetyl ester NF 1, cetyl alcohol 2, cetyl acetate 4, isopropyl myristate 5 (the response Fulton used to DEFINE the top of his scale), and myristyl myristate 5 — none of which is this material. Fulton records no supplier, purity or batch for any row, so the identity match is at the level of the printed name. He called his survey "not at all definitive but simply designed to stimulate research." acne.org, CosDNA and the rest republish this row; they are the same reading quoted again, not independent corroboration.
- Cosmetic Ingredient Review. "Final Report on the Safety Assessment of Octyl Palmitate, Cetyl Palmitate and Isopropyl Palmitate." J Am Coll Toxicol 1(2):13-35 (1982) An expert-panel SAFETY assessment, read here via its published abstract and summary rather than the full report — so we describe what those state and do not characterise the panel's complete dossier. Cited for two narrow things: the material's identity — cetyl palmitate is a wax ester, a major constituent of spermaceti, made synthetically for cosmetics — and the panel's conclusion that it is safe as used, resting on toxicity, irritation and sensitisation evidence (oral LD50 in rats greater than 14.4 g/kg; non-irritating and non-sensitising in the skin tests reported). It is a safety review, NOT a comedogenicity study: it weighs toxicity and irritation, not follicular plugging, and it is not evidence for or against a comedogenic rating. We do not use it as one. Its use data are from the early 1980s and are not a current market survey.
- 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, thirty-two rows, materials applied undiluted unless stated and graded microscopically — the one legacy paper that could have given cetyl palmitate a second reading. Cited here for what it does NOT contain: it scores isopropyl palmitate 3 and octyl palmitate 2-3, two different esters, but it has no row for cetyl palmitate at all. Neither of those numbers transfers. So we found no independent corroboration of Fulton's 0 in the legacy corpus we hold. Morris and Kwan are also on record contradicting Fulton in print on other materials, which is worth knowing when weighing a number that rests on Fulton alone.
- Fulton JE Jr, Pay SR, Fulton JE III. "Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear." J Am Acad Dermatol 10(1):96-105 (1984). PII S0190-9622(84)80050-X Fulton's own earlier rabbit-ear paper, read from a 400dpi render of the journal scan. Method: two New Zealand albino rabbits per test, one ear dosed daily for two weeks, the other ear the control. Cited only for an absence: its Table I has no cetyl palmitate row, so it neither corroborates nor contradicts the 1989 zero. Note also that its scale key is not the 1989 key — 1984 calls 1 to 2 not significant and 3 or above positive — so its numbers cannot be read against 1989's without carrying each paper's own threshold. The neighbouring rows it does print (isopropyl palmitate 4, cetyl alcohol 3) belong to other materials.
- Draelos ZD, DiNardo JC. "A re-evaluation of the comedogenicity concept." J Am Acad Dermatol 54:507-512 (2006) A "Current Issues and Opinion" piece in JAAD that tested finished products on human upper backs and found products testing non-comedogenic despite containing ingredients the rabbit assay had scored comedogenic. Cited because it cuts against a reassuring rabbit-ear grade exactly as much as an alarming one: it is evidence that an isolated ingredient's score does not transfer intact to the formula it ends up in. It is not a same-substance rabbit-versus-human validation, and we do not present it as one.
- "Comedogenicity in cosmeceuticals: a review of clinical relevance, regulatory gaps, and future directions." JAAD Reviews (2025) A recent peer-reviewed review of the whole field, covering literature from 1972 onward. It is a synthesis, not a new measurement, and a review of this literature necessarily takes in Fulton rather than standing apart from him; what it is not is one of the consumer lists that republish his table. Cited for the field-wide caveat that no standardised comedogenicity test exists and that "non-comedogenic" is an unregulated label — the caution that governs every number on this page, the reassuring 0 included.
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