Porecelain

Flawless skin starts with the fine print.

Oleyl Alcohol

Oleyl alcohol is one of the ingredients on this site whose circulating 4 actually belongs to it: Fulton's table prints "Oleyl alcohol, 4" on a 0 to 5 scale, for oleyl alcohol, and he reported the same 4 five years earlier — a positive result by his own key, both times, and the only comedogenicity readings of it we can find.

Clogging Low confidence Legacy score 4 on a 0-5 scale · Fulton 1989 · low reliability

Large unsaturated fatty alcohol flagged comedogenic by legacy assays.

What it is

As a pure compound, a single unsaturated fatty alcohol: cis-9-octadecen-1-ol, eighteen carbons long with one double bond in the middle of the chain (formula C18H36O, formula weight about 268). What is sold commercially is a grade-dependent fatty-alcohol cut rather than that pure compound, and neither paper that scored it reports purity, isomer split or supplier. The double bond is what sets it apart from stearyl alcohol, its saturated twin: remove the double bond and you have stearyl alcohol, a waxy solid; keep it and you have oleyl alcohol, an oily liquid at room temperature. The word "alcohol" is where the pore-clogging worry comes from, and as with the other fatty alcohols it is misleading — this is not the drying ethanol of a toner but a large, oily, water-insoluble molecule that has to be blended into a formula. Formulators use it as an emollient and a spreading agent, as a co-emulsifier, and to give a product slip and a lighter feel than the solid waxes give. It also turns up as a raw material in the manufacture of other ingredients. We have not audited how often it appears on labels or at what concentration, so we make no claim about either.

Why we rate it Clogging

We rate it Clogging, at Low confidence, and the two halves of that sentence are both worth stating plainly. The number is real and it is a positive result. It is also the reading of one man, in one laboratory, on rabbit ears, and we identified no other reading of it. The measurement is James Fulton's 1989 rabbit-ear survey in the Journal of the Society of Cosmetic Chemists. The alcohols block of his table prints "Oleyl alcohol" and scores it 4 for comedogenicity on a 0 to 5 scale. We render the table at 400dpi and read all 220 rows by eye, because OCR drops the numeric columns, and this row says what it appears to say. That is worth stating, because on much of this site it does not: coconut oil has no row and the famous 4 belongs to coconut butter; rosehip oil has none at all. Oleyl alcohol has its own row, and the 4 is attached to oleyl alcohol. There is no substitution to unpick here. The score carries no qualifier. It sits in Fulton's alcohols section, not his oils section, so the section asterisk that reads "results depend on source of raw material" — the one that hangs over every oil and butter he tested — does not apply to it. It is a bare 4, not a 4 with a footnote and not a range. And by Fulton's own key, 4 is a finding. He wrote that "a minimal grade of 0 to 1 is not considered significant. Grade 2 to 3 is borderline. However, a grade of 4 to 5 is uniformally reproduceable and considered positive." So this is not the borderline 2 that cetyl and stearyl alcohol carry, which we rate Clear. It is in the band he called positive, above his own line for a real result. The method behind it: the ingredient at roughly 10 percent in propylene glycol, 1 ml applied to the inner ear of New Zealand albino rabbits, three rabbits per assay, five days a week for two weeks, follicular keratosis measured with a micrometer. Fulton reported the same number once before. His earlier survey — Fulton, Pay and Fulton 1984, now read in full off the journal scan — also scores oleyl alcohol 4. The 1984 paper used a different threshold, "1 to 2 is not significant, 3 or above is considered positive", so a 4 is a positive there too. Two readings, five years apart, that agree exactly and both land in the positive band. That is more internal consistency than most ingredients on this site can show, and it is why the rating is Clogging rather than a shrug. It is also the whole of the direct evidence, and both readings are Fulton's. That matters because the other 0-to-5 rabbit-ear survey did not test it. Morris and Kwan's 1983 paper — seven lanolins, nine vegetable oils, eleven esters, five surfactants — has no oleyl alcohol row, and it is the paper that openly contradicts Fulton in print on other materials. The 2007 Nguyen, Dang and Maibach rabbit study did not include it either. So no other laboratory appears in the record we hold, agreeing or disagreeing. There is Fulton, twice. One more observation from the table itself, offered as a pattern and not a mechanism. Among the fatty alcohols Fulton scored, the straight saturated ones sit low — cetyl alcohol 2, stearyl alcohol 2, cetearyl alcohol 2 — and it is the branched isocetyl alcohol (4) and the unsaturated oleyl alcohol (4) that score higher. It is tempting to explain that by the shape of the molecule. We will not: that would be inventing a mechanism from one man's ingredient set, and Fulton's own structural hypotheses were about his data, not laws of the follicle. What we can say is only what the column says — within his single table, this alcohol scored twice as high as its saturated relatives.

What the evidence doesn’t tell you

The direct evidence is two rabbit-ear readings by one investigator, and it is the same assay we discount everywhere else on this site. The reasons do not stop applying because the result points the way people expect. Draelos and DiNardo argued in 2006 that rabbit-ear results do not reliably transfer to human skin, and a 2025 JAAD Reviews survey of the field found that no standardised comedogenicity test exists and that "non-comedogenic" is an unregulated claim. Those are the grounds on which we refuse to trust a rabbit-ear 0 as proof of safety. They apply with equal force to a rabbit-ear 4: a positive on the inner ear of three rabbits, at about 10 percent under a repeated rabbit-ear application protocol, is a signal to take seriously, not a measurement of what the ingredient does on a human face. We identified no study that counted comedones on human skin after applying oleyl alcohol. Both numbers we have are Fulton's, both are rabbit, and we identified no independent laboratory reading in the record we searched — not agreeing, not disagreeing. There is a trap next to this ingredient that has to be named, because it is exactly the kind of thing that lands a wrong number on a page. Oleyl alcohol is not oleic acid. They share a chain length and a double bond, but one ends in a hydroxyl group and the other in a carboxylic acid, and they are different molecules with different assays. Oleic acid has its own comedogenic literature — Kanaar's 1971 rabbit study recorded "marked inflammation and follicular keratosis" from it, and a 1983 study found oleic acid peroxides enhanced comedone formation — but none of that is evidence about oleyl alcohol, and it must not be read across. If you see oleyl alcohol's rating defended or attacked with a study of oleic acid, the study is about a different compound. Finally, the Cosmetic Ingredient Review's assessment of this ingredient is a safety review, not a comedogenicity one. The CIR's 1985 final report on stearyl alcohol, oleyl alcohol and octyldodecanol concluded them safe as used in cosmetics, and a 2004 re-review reaffirmed it. That is a conclusion about toxicity, irritation and sensitisation. Safety is not the same question as comedogenicity, and a body clearing an ingredient as safe has not cleared it as non-clogging.

Where you’ll see it

As an emollient, thickener and co-emulsifier, most often in creams, lotions, cleansing products and hair conditioners, and as a feedstock for making other cosmetic ingredients. Those are illustrative categories, not a measured prevalence — we have not surveyed the market, and label position is not a dose. Nearby you will often meet stearyl alcohol, cetyl alcohol and cetearyl alcohol; they are relatives, they carry different (and lower) numbers, and the evidence on this page does not transfer to them.

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 most-quoted source, and the one that gives the 4. Design — ingredient at roughly 10% in propylene glycol, 1 ml applied to the inner ear of New Zealand albino rabbits, three rabbits per assay, five days a week for two weeks, follicular keratosis measured with a micrometer. Scale 0 to 5. Oleyl alcohol appears in the alcohols block of the table, scored 4 for comedogenicity, with no asterisk and no range. What it cannot support — Fulton calls the survey "not at all definitive but simply designed to stimulate research", warns that the rabbit ear is so sensitive that "not everything that irritates this model will also irritate human skin", and by his own key a 4 is "considered positive" on the ear, which is not the same as a measurement on a face. One animal assay in one laboratory.
  2. 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 survey, now read in full off the journal scan (print copy obtained 2026-07-18). Its Table I scores oleyl alcohol 4, the same number as 1989. Method — two New Zealand albino rabbits per test, one ear dosed daily for two weeks, the other ear the control; liquids and soft solids applied "as is". Its key is not the 1989 key: in 1984 Fulton wrote "1 to 2 is not significant… 3 or above is considered positive", so this 4 is a positive by 1984's bar as well. Cited as the second reading — and as the reminder that both readings we hold come from the same author and the same model.
  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) The other major rabbit-ear survey on the same 0 to 5 scale — undiluted material unless otherwise stated, three rabbits, 14 applications, microscopic grading. Cited here for what it does NOT contain: its 32 rows cover lanolins, vegetable oils, esters and surfactants, and oleyl alcohol is not among them. It is the paper that would most plausibly have corroborated or contradicted Fulton's 4, and it did neither. It matters for a second reason — it contradicts Fulton in print on other materials, which is why two Fulton readings cannot be read as "the literature agrees".
  4. Cosmetic Ingredient Review. "Final Report on the Safety Assessment of Stearyl Alcohol, Oleyl Alcohol, and Octyl Dodecanol." J Am Coll Toxicol 4(5):1-29 (1985) A final report — the published, panel-adopted document state, not a tentative or comment-stage draft — from an industry-funded but independently panelled toxicological review; its conclusion that these alcohols are safe as used was reaffirmed on re-review in 2004. Cited for the material identity and the safety conclusion, and cited AGAINST being read as comedogenicity evidence: its endpoints are toxicity, irritation and sensitisation, and a "safe as used" finding is not a "non-comedogenic" one.
  5. 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, not a same-substance rabbit-versus-human validation study. It argues that rabbit-ear results do not reliably predict comedogenicity in human skin and that an isolated ingredient says little about a finished formula. Cited to hold the confidence Low: the argument that undermines a convenient rabbit-ear 0 undermines an inconvenient rabbit-ear 4 just as much.
  6. Kanaar P. "Follicular-keratogenic properties of fatty acids in the external ear canal of the rabbit." Dermatologica 142(1):14-22 (1971) A qualitative rabbit-ear-canal study of fatty ACIDS — read via its EuropePMC abstract, full text not obtained. Recorded "marked inflammation and follicular keratosis" from oleic acid. Cited here only to mark the boundary: oleic acid is a different molecule from oleyl alcohol (an acid, not an alcohol), and this paper is NOT evidence about oleyl alcohol. Included so the near-name confusion is disclosed rather than smuggled in as support.
  7. Acne.org, "What Is Comedogenicity, and What Ingredients Are Comedogenic? The Full Story" (updated 24 March 2025) A commercial acne-products site that also publishes an ingredient list, on which oleyl alcohol appears. Cited to characterise the secondary literature accurately: it states a rule for its list and cites primary papers rather than inventing numbers, but it is still a compilation of other people's assays, with no measurement of its own, and does not tell you which study produced which score.

Others in the same family

Fatty alcohols 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 fatty alcohols as a family ›

Last reviewed 2026-08-12 · How we decide

‹ Check a full ingredient list