Peanut Oil
Peanut oil is one of the oils where the legacy number is real, checkable, and printed against the same generic name that appears on labels — but the only comedogenicity assay we can find is a single 1989 rabbit-ear reading. Fulton scored it 2 of 5, the bottom of the band he called "borderline," and we can find no other laboratory and no human study that has tested this oil since. We rate it Caution on that one reading.
Heavy nut oil with a low-to-moderate legacy clog score.
What it is
The oil expressed from the seed of the peanut, or groundnut, Arachis hypogaea — a legume, not a nut in the botanical sense, though it behaves like a heavy vegetable oil on skin. On a label it is Arachis Hypogaea (Peanut) Oil. The Cosmetic Ingredient Review's 2001 safety assessment lists its cosmetic functions as emollient, solvent and skin-conditioning agent, and describes its major fatty acids as palmitic, oleic and linoleic — with smaller amounts of the longer-chain saturated acids arachidic (C20), behenic (C22) and lignoceric (C24). Arachidic acid takes its name from Arachis; those long-chain saturates are part of what distinguishes peanut oil from a plainer oleic/linoleic oil. (We read the report's abstract and CIR's own consumer summary; the full assessment is paywalled, and we are not quoting figures from inside a document we have not opened, so the composition here is qualitative on purpose.) It is sold in refined and cold-pressed grades. The grades differ in retained protein, which is an allergy question and is set out below; what the grade does to the pore endpoint is unknown, since no assay we hold compares them and Fulton's oils section carries the footnote "Results depend on source of raw material."
Why we rate it Caution
We rate it Caution. The evidence is a single rabbit-ear assay, and it is worth being exact about what that assay says and does not say. Fulton's 1989 table — the source nearly every comedogenic number online descends from — prints Peanut oil at 2, in section VI, "Oils." We read the row off a render of the journal scan rather than off a list quoting it, and it is genuinely there: this is not coconut oil, where the famous number belongs to coconut butter, nor rosehip, where there is no row at all. Fulton tested peanut oil, and the name he printed matches the generic name a label carries — though he records no grade, cultivar or supplier, so the match is one of generic name only. What the 2 meant to him matters, because the charts that republish his numbers drop his own key: "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 peanut oil's 2 is the floor of the borderline band — above "not significant," well below "positive," and not a clean pass. It is printed as a bare 2, with no parenthetical "refined oil" figure of the kind Fulton gives for sesame 3(1)**, avocado 3(2) or olive 2(1); and the section carries his heading footnote, "Results depend on source of raw material," which applies to this oil as much as to the butters above it. What is missing here is the thing corn oil has and peanut oil does not: a second reading. Morris and Kwan, whose 1983 rabbit-ear assay is the other complete 0-to-5 table we hold, tested thirty-two materials — including several vegetable oils — and peanut oil is not among them. Of the four numeric inventories we hold — Fulton 1989, Fulton 1984, Morris and Kwan 1983, and Nguyen 2007 — only the first carries a peanut oil row at all. So this is one laboratory, one decade, one unspecified grade, with no confirming or contradicting reading in the sources we searched. That is not the same as two labs agreeing, and it is not the same as two labs disagreeing; it is a single unreplicated reading, and Caution reflects it at face value. A reader who treated one low-borderline rabbit score as close to Clear would not be reading the evidence wrongly — there simply is not enough of it to be firm, and we are not going to manufacture firmness the data does not carry.
What the evidence doesn’t tell you
We identified no human study of peanut oil's comedogenicity — not on a face, not on a back, not with a comedone count — and no comedogenicity assay of it other than Fulton's. Everything the rating rests on happened inside the ear of a rabbit: the ingredient at roughly 10% in propylene glycol, applied to the inner ear of New Zealand albino rabbits, follicular keratosis scored by microscope. Fulton called his own 220-row survey "not at all definitive but simply designed to stimulate research," and warned the rabbit ear is sensitive enough that "not everything that irritates this model will also irritate human skin." A single number from one batch of one oil in one decade, under a section footnote that says the result depends on the source of the raw material, is not a promise about the bottle in hand — and peanut oil is sold in high-oleic and ordinary cultivars whose fatty-acid profiles differ, though they share one INCI name. The composition invites a mechanism, and we are going to leave it uninvited. The comedogenic-rating blogs assert that peanut oil's oleic-acid content "disrupts the skin barrier and increases inflammation." The oleic-versus-linoleic sebum literature is real, but it has not been tested on this oil, and a mechanism that would explain a result is not additional evidence for one. No comedogenicity measurement of peanut oil supports the oleic-acid story, so we are not going to print it as though someone had run that study. Related drift worth flagging: several charts round the figure up to "2–3," but Fulton printed 2. Two things that are not comedogenicity data, flagged so they are not mistaken for it. The CIR's 2001 assessment concludes peanut oil and its derivatives are safe as used in cosmetics — but safety and follicular plugging are different questions, and the report says nothing about pores. And the field-wide caveat, from a 2025 review in JAAD Reviews surveying the literature from 1972 on: no standardised comedogenicity test exists, and "non-comedogenic" is an unregulated label.
Where you’ll see it
On a label it appears as Arachis Hypogaea (Peanut) Oil. Per the CIR's 2001 assessment it is used as an emollient, solvent and skin-conditioning agent, so it turns up in creams, lotions, soaps, bath and massage oils and some colour cosmetics, and it also serves as a plain carrier oil. One thing a reader meeting peanut oil on a cosmetic label is likely to want, kept separate because it is an allergy question and not a pore one: whether it poses a risk to people with peanut allergy. The allergens are proteins. The CIR's 2001 report states that the major peanut allergen does not partition into peanut oil, and Hourihane and colleagues, in a 1997 randomised, double blind, crossover challenge of sixty allergic subjects (BMJ 314:1084–1088), reported that "None of the 60 subjects reacted to the refined oil; six (10%) reacted to the crude oil." That is a clinical finding about the refined oils they tested, not a general rule that refining removes the allergen from every grade or batch. The distinction has nothing to do with comedogenicity, which is why it lives here and not in the rating.
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 our legacy score and of nearly every comedogenic number in circulation. Method: the ingredient at 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. Read off a render of the journal scan, not off a list quoting it. Its Table I, section VI "Oils," prints Peanut oil at 2 — a bare 2, with no parenthetical "refined oil" figure of the kind it gives for sesame 3(1)**, avocado 3(2) and olive 2(1). It also supplies the grade key the lists omit — 0 to 1 "is not considered significant," 2 to 3 is "borderline," 4 to 5 is "considered positive" — and the section footnote on every oil and butter row: "Results depend on source of raw material." Fulton called the survey "not at all definitive." This is the only comedogenicity assay of peanut oil we have found.
- 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 complete 0–5 rabbit-ear table we hold, from a different laboratory six years before Fulton, on the same scale — cited here for what it does NOT contain. It tested thirty-two materials, several of them vegetable oils, and peanut oil is not among them. It is why this page can say we found no second reading of the 2 — the obvious place to look for a confirming or contradicting reading does not have one. It is also not a deferential republication of Fulton — the same paper openly contradicts him on sodium lauryl sulfate — so its silence on peanut oil is a genuine gap, not an omission of a number it was copying.
- Cosmetic Ingredient Review Expert Panel. "Final Report on the Safety Assessment of Peanut (Arachis hypogaea) Oil, Hydrogenated Peanut Oil, Peanut Acid, Peanut Glycerides, and Peanut (Arachis hypogaea) Flour." Int J Toxicol 20(Suppl 2):65–77 (2001) An independent expert-panel safety review, not a comedogenic list and not downstream of Fulton. Cited for what it can actually support: the cosmetic functions (emollient, solvent, skin-conditioning agent), the qualitative fatty-acid composition (major acids palmitic, oleic and linoleic, with smaller arachidic, behenic and lignoceric fractions), and the allergen finding that the major peanut protein does not partition into the oil. Full text paywalled; we read the abstract and CIR's consumer summary and are not quoting interior figures, so the composition on this page is qualitative. It assesses safety, not comedogenicity, and says nothing about pores.
- Hourihane JO'B, Bedwani SJ, Dean TP, Warner JO. "Randomised, double blind, crossover challenge study of allergenicity of peanut oils in subjects allergic to peanuts." BMJ 314(7087):1084–1088 (1997). DOI 10.1136/bmj.314.7087.1084 A randomised, double blind, crossover food-challenge study in sixty peanut-allergic subjects, comparing refined and crude peanut oil. Its result, verbatim: "None of the 60 subjects reacted to the refined oil; six (10%) reacted to the crude oil." Cited only for the refined-versus-crude allergen distinction in the where-seen section — it is an oral food-allergy study, and it has nothing to do with comedogenicity. Included because it is the kind of real, specific evidence the allergen question actually has, and the pore question does not.
- "Comedogenicity in cosmeceuticals: a review of clinical relevance, regulatory gaps, and future directions." JAAD Reviews (2025) Recent peer-reviewed review of the whole field, covering the literature from 1972 onward. It is a synthesis of the legacy literature, not a new measurement, and independent of Fulton only in authorship, since the corpus it surveys includes his. Finds that no standardised comedogenicity test exists and that "non-comedogenic" is an unregulated label. Cited for the field-wide caveat, not for anything specific to peanut oil.
- acne.org comedogenic ingredient list, and the comedogenic-rating charts generally Where a reader will most likely have met peanut oil's "2." These charts republish the Fulton 1989 rabbit-ear scores; they are not independent measurements, and neither are CosDNA, Face Reality or Banish. On peanut oil they pass along the number without Fulton's grade key — so a borderline-floor 2 arrives looking like a settled verdict — and several of them round it up to "2–3," which Fulton did not print. Cited as the genealogy of the circulating figure, not as corroboration.
Others in the same family
Oils 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 oils as a family ›
Last reviewed 2026-08-12 · How we decide