Octyl Palmitate
Octyl palmitate is rated Clogging, and its number is one of the better-supported on this site: two rabbit-ear assays placed it in borderline-to-positive territory, and — rarely for a comedogenic score — it also has human data, because octyl palmitate is the reference comedogen human comedogenicity assays use to check the test is working, and one 2021 trial published the counts.
Human trial in 15 men — comedones rose 365% in 4 weeks; Fulton 1989 scored it 4 of 5.
What it is
Octyl palmitate is the ester of palmitic acid, the sixteen-carbon saturated fatty acid, and 2-ethylhexanol, an eight-carbon branched alcohol. The "octyl" in the older name is that branched eight-carbon group, which is why the modern INCI name for the identical material is Ethylhexyl Palmitate; both names carry the same CAS number, 29806-73-3, and the same formula, C24H48O2. This matters below, because the primary literature is split across both names: Fulton's 1989 table prints it as "Ethylhexyl palmitate," while Morris and Kwan and the human-assay work call it "Octyl palmitate." They are one material under two labels, not two esters — the reverse of the usual trap on this site, where one label hides two different materials. A formulator reaches for it as a light, dry-feeling emollient. It is a clear, near-odourless, low-viscosity liquid that thins heavier oils, cuts greasiness, spreads with a silky slip and leaves little residue, and it doubles as a solvent, a pigment-wetting agent and a fragrance fixative. Those are properties of the molecule; none of them, on its own, says anything about pores.
Why we rate it Clogging
We rate it Clogging. What this page adds is that the number behind that rating is, unusually, backed by more than a rabbit ear. Where the number comes from. James Fulton's 1989 survey in the Journal of the Society of Cosmetic Chemists is the source of nearly every comedogenic score in circulation, and we read its Table I off a render of the journal scan rather than a list quoting it. Among the esters it prints a row for ethylhexyl palmitate — octyl palmitate under its current INCI name — at a comedogenicity grade of 4 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," 2 to 3 is "borderline," and only "a grade of 4 to 5 is uniformally reproduceable and considered positive." So the 4 sits in the one band he treated as a real finding. The row carries no asterisk, which matters: the asterisk Fulton attached to his oils — "results depend on source of raw material" — is a section heading over his oils and butters, and it does not reach this ester. And the 4 is a reading, not the ruler — Fulton defined the top of his scale by isopropyl myristate, not by this material. A second reading, in a different laboratory. Morris and Kwan, in 1983 — six years before Fulton — ran their own rabbit-ear assay on the same 0-to-5 scale and scored octyl palmitate 2 to 3, applied undiluted. That is not Fulton's 4, and we are not going to round the two into a single verdict they do not jointly print; the two labs disagree on magnitude, and Fulton's more-dilute test returning the higher number is itself a caution against reading these grades too precisely. What they agree on is direction: both placed this ester at or above the borderline band, neither near zero. Then the part that sets this ester apart from almost every other number on the site: there is human evidence, and it points the same way. Octyl palmitate is the reference comedogen — the positive control — in the modified Mills and Kligman human comedogenicity assay. Draelos and DiNardo, in 2006, ran that assay on six people with prominent follicles and a known ability to form comedones, patching finished products to the upper back three times a week for four weeks and counting microcomedones by cyanoacrylate biopsy; octyl palmitate was the substance they trusted to reliably raise those counts, which is the working definition of a positive control. It earns that role by producing comedones on human skin, not a rabbit's. And in 2021 a trial published the counts. Waranuch and colleagues, running a controlled study of an anti-acne formulation in fifteen healthy men aged 20 to 45 with prominent follicular orifices, used an octyl palmitate pad on the upper back as their positive control for four weeks, then took epidermal biopsies and counted comedones under a stereomicroscope. The octyl palmitate site went from 6.1 ± 0.6 comedones at baseline to 27.3 ± 4.7 at four weeks — an average change of 365.4 ± 87.6 percent, with every analysed subject showing more than a 50 percent increase. The negative control fell over the same period, from 6.4 ± 1.1 to 3.4 ± 0.6. That is a same-material comedone count on human skin, with numbers attached, and it is the strongest single item on this page. So the rating is Clogging, and the honest account of the evidence is this: two rabbit-ear assays put octyl palmitate in borderline-to-positive territory, and — rarely for a number on this site — human work counted comedones on human skin after applying this exact material and found them multiplied. That is more, and better, evidence than most ratings here can claim. What none of it settles is the concentration question, which the next section takes up.
What the evidence doesn’t tell you
Concentration is the practical caveat, and this page can no longer put a number on it. An earlier version of this page printed a dose-response series — the neat material 2 to 3, a 50% dilution 1, a 5% dilution 0 — and attributed it to Draelos and DiNardo 2006. We can no longer support that: the series is printed on a 0-to-5 scale, the modified Mills and Kligman human assay it was attributed to grades on 0 to 3, and we could not locate the series in either of the papers it was credited to. It has been removed rather than re-attributed, and nothing has replaced it. What survives is the principle without the figures. A comedogenic grade is a property of a material at a concentration, not a fixed trait it carries into a formula: Waranuch's positive control was an octyl palmitate pad, Morris and Kwan applied the ester undiluted, Fulton tested it at roughly 10% in propylene glycol. A leave-on product rarely contains an emollient ester at anything like those strengths, so the rating describes the material at strength and does not tell you what a few percent of it does inside a finished lotion. We cannot tell you where the threshold sits, because we did not read a study that measured one. Draelos and DiNardo's headline finding was that finished products built from comedogenic ingredients frequently tested non-comedogenic; Fulton, for his part, distrusted that reassurance: his conclusion reads, "We are not convinced of the statement that lower concentrations of these compounds can be safely used with no comedogenic consequences." Both cautions are on the record, and they point in opposite directions. The two rabbit assays rest on rabbit ears. Fulton's method: the ingredient at roughly 10% in propylene glycol, about 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. Morris and Kwan used the ear canal and applied the material undiluted. The two labs also differ on magnitude, not only on protocol: Morris and Kwan graded it 2 to 3 undiluted, Fulton a 4 at roughly 10% in a different regime. They agree on direction and disagree on size, and we are not going to average them. Fulton said plainly that the rabbit ear is more sensitive than human skin and warned that "not everything that irritates this model will also irritate human skin." The human work narrows that gap for this ester — but both human studies used the material as a positive control at one strength, on backs rather than faces, so the concentration at which octyl palmitate stops mattering in a real product is not something these papers pin down. We are not going to tell you why it clogs. The obvious temptation is a mechanism — that the light ester spreads into the follicle and holds sebum against the wall — and the content mills state exactly that as fact. None of the assays here demonstrates a mechanism; they counted comedones, they did not explain them. A mechanism asserted to dress up a rating is not evidence. Human evidence, stated precisely: in both human studies octyl palmitate's role is as the positive control, and a positive control's job is to demonstrate that subjects can form comedones, not to map a curve. Waranuch's trial reports counts for one application regime at one strength; Draelos and DiNardo report no counts for the control at all. We identified no study that applied isolated octyl palmitate to human skin across a range of concentrations and reported the counts as a dose-response. Two rabbit surveys we would expect to corroborate the ester are also quiet: Nguyen, Dang and Maibach's 2007 rabbit assay lists several esters, including isopropyl palmitate, among its positives but we did not find octyl palmitate among them, and Fulton's earlier 1984 paper names octyl palmitate in its text as an offender but prints no numeric grade for it, so we carry no number from either. The assay tradition has been contested for decades, and here the objections cut toward the number as much as away from it. Frank asked in 1982 whether the rabbit ear predicts human acne at all. A 2025 review in JAAD Reviews found that no standardised comedogenicity test exists and that the label "non-comedogenic" is unregulated. Those cautions apply to a positive grade exactly as much as to a reassuring one.
Where you’ll see it
On a label it appears as Octyl Palmitate or, more often now, Ethylhexyl Palmitate — the same material. It is a common lightweight emollient in leave-on products where a dry, silky, non-greasy slip is wanted: moisturisers and lotions, sunscreens, cream and stick colour cosmetics, cleansers and makeup removers, and hair care, where it also acts as a solvent and pigment-wetter. We have not audited its market share, and label position is not a dose, so treat that as the categories it suits rather than a measured prevalence. The Cosmetic Ingredient Review's assessment of the alkyl esters treats ethylhexyl palmitate as safe as used at the levels it reviewed; that is a judgement about toxicity and irritation, not about pores, and the two questions are separate. The practical note is the two names. "Octyl Palmitate" and "Ethylhexyl Palmitate" are the same ester, so a checker that recognises one should recognise the other; the comedogenic number belongs to both equally. Do not confuse it with octyldodecyl stearate, a different, longer ester Fulton scored 0, or with isopropyl palmitate, the neighbouring palmitate ester on its own page.
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, 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 "Ethylhexyl palmitate" — octyl palmitate under its current INCI name — at a comedogenicity grade of 4 on a 0-to-5 scale, with no asterisk, in the esters section rather than the asterisked oils section. Fulton's own key: 0 to 1 "not considered significant," 2 to 3 "borderline," 4 to 5 "considered positive." He called the survey "not at all definitive but simply designed to stimulate research." acne.org, CosDNA, Face Reality and the rest republish this row; they are the same assay quoted, not independent corroboration.
- 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 and in a different laboratory — not a republisher of him. It scores octyl palmitate 2 to 3, applied undiluted. Cited as the second rabbit reading this page has: a different lab, testing the same named ester, placing it at or above the borderline band, though a notch below Fulton's 4. Morris and Kwan are also on record contradicting Fulton on other materials, so agreement here is not two labs that always agree.
- 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 whose headline finding is that finished products built from comedogenic ingredients often test non-comedogenic on human skin. It ran a modified Mills and Kligman human assay — six people with prominent follicles, patches of finished product to the upper back three times weekly for four weeks, microcomedones counted by cyanoacrylate biopsy — and used OCTYL PALMITATE as the positive control, the reference comedogen the assay relies on to confirm subjects can form comedones. That is this page's human evidence: octyl palmitate reliably produces comedones on human skin, which is why it is trusted as the control. It reports no comedone count for the control arm itself, and no dose-response for it. It is NOT a same-substance rabbit-versus-human validation of the whole scale, and we do not present it as one; its finished-product arm cuts against reading any isolated ingredient score straight into a formula.
- Waranuch N, Phimnuan P, Yakaew S, et al. "Antiacne and antiblotch activities of a formulated combination of Aloe barbadensis leaf powder, Garcinia mangostana peel extract, and Camellia sinensis leaf extract." Contemp Clin Trials Commun 23:100834 (2021). PMID 34471722 The strongest human evidence on this page, and the reason its confidence is not Low. A controlled human study in fifteen healthy men aged 20 to 45 with prominent follicular orifices, in which an octyl palmitate pad applied to the upper back for four weeks served as the POSITIVE CONTROL; comedones were counted on epidermal biopsies under a stereomicroscope in the twelve subjects analysed. The octyl palmitate site rose from 6.1 ± 0.6 comedones at baseline to 27.3 ± 4.7 at four weeks, an average change of 365.4 ± 87.6 percent, with every analysed subject above a 50 percent increase; the negative control fell from 6.4 ± 1.1 to 3.4 ± 0.6. What it establishes: this exact material induces comedones on human skin, with counts. What it does not: the study's subject is the test formulation, not octyl palmitate, so there is no concentration series, no facial site, and no comparison against the rabbit grades.
- 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) Fulton's earlier rabbit-ear paper, on the same 0-to-5 scale, read in full off the journal scan. Cited for a distinction that is easy to blur: it NAMES octyl palmitate in its text as one of the offenders, but prints no numeric row for it. A prose classification is not a measured score, so we carry no number from this paper — only the observation that its authors already regarded the ester as a problem five years before the 1989 table gave it a grade.
- Cosmetic Ingredient Review. "Amended Safety Assessment of Alkyl Esters as Used in Cosmetics." An expert-panel safety assessment covering ethylhexyl (octyl) palmitate among the alkyl esters, cited for one narrow thing: it establishes that the ingredient is a widely used cosmetic emollient the panel judged safe as used at the concentrations reviewed. A safety assessment weighs toxicity, irritation and sensitisation — not follicular plugging — so it is not evidence for or against a comedogenic rating, and we do not use 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 of the legacy literature, not a new measurement, and independent of Fulton only in authorship — the corpus it surveys includes his. 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 alarming ones and the reassuring ones alike.
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 2026-08-05 · How we decide