Kaolin

Kaolin is rated Clear, and the 0 behind that rating is printed under the name on the label — which is not something this site gets to write often, though neither paper records the source, grade, purity or particle size of the clay behind it. What the charts leave out is that Fulton graded kaolin twice, in two papers, and printed two different numbers: 0 on a 0–5 scale in 1989, and 1 on the same scale in 1984, in a different vehicle. Both fall on the not-significant side of each paper's own published key, and both are the same investigator reading the same animal model.

What it is

A mined clay. The US Geological Survey describes kaolin as "a claystone composed primarily of kaolinite", and kaolinite as a clay mineral with the formula (Al2Si2O5)(OH)4, formed largely by soil processes — most commonly the chemical breakdown of feldspars, with calcium, sodium and potassium leached away to leave the aluminium-rich product. USGS puts US production at about 6 million tons a year, mostly in Georgia, and lists paper coating, ceramics and refractories as its principal uses. The cosmetic material is a processed grade of that mineral, not the rock. In cosmetics it is a powder that does powder jobs. The Cosmetic Ingredient Review's 2003 final report on this ingredient group states that clay silicates — silicates containing water in their structure — "primarily function as adsorbents, opacifiers, and viscosity-increasing agents". Kaolin is also a drug ingredient in its own right: the FDA's over-the-counter monograph for skin protectant drug products lists it at 21 CFR 347.10(j) as an active ingredient at 4 to 20 percent; the same listing is carried in FDA's OTC monograph system as Monograph M016, section M016.10(j), established by Final Administrative Order OTC000005, which we have not read and record here unverified by us. On a label it is simply Kaolin.

Why we rate it Clear

We rate it Clear at Low confidence. Low because the entire numeric evidence base is rabbit-ear grading from one investigator, which is the tier that gets Low here whichever way it points. The 1989 row, and what the match to it amounts to. Fulton's 1989 survey in the Journal of the Society of Cosmetic Chemists prints "Kaolin" in Table I at a comedogenicity grade of 0 on a 0–5 scale, with no asterisk and no range. We read that off our own 400dpi transcription of the table rather than a chart quoting it. The name printed in the paper is the name the score is quoted under, with nothing dropped from it — worth stating plainly, because on this site that is the exception rather than the rule. Fulton's own grade key, published on p. 322 and rarely quoted beside his numbers, reads "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." A 0 is as low as that scale goes. The row sits in the table's powders and thickeners cluster. Its immediate neighbours are bentonite 0, magnesium aluminum silicate 0, carbomer 940 1, talc 1 and PVP 0. That is a description of how one table is laid out, not five further experiments on kaolin, and it does not raise our confidence in the 0. The second reading, which the charts do not carry. Fulton's earlier paper with Pay and Fulton, in the Journal of the American Academy of Dermatology in 1984, ran the same model over therapeutic products, cosmetics and ingredients on the same 0–5 scale. Its Table I prints "Kaolin" at 1, with the paper's asterisk against the name, under "Miscellaneous ingredients", beside hectorite — another clay — also at 1. Two details belong to that paper and must travel with its number. Its asterisk is not the 1989 asterisk: the 1984 footnote reads that the product or ingredient "was used 'as is' if the agent was a liquid or soft solid. Others (*) were either diluted with mineral oil or incorporated into an alcohol gel at a 10% concentration." So the 1984 kaolin sample was diluted, though the page does not say into which of the two. And its threshold is drawn in a different place: "a minimal grade of 1 to 2 is not considered significant. However, a grading score of 3 or above is uniformly reproducible and considered positive." So the two readings are 0 of 5 and 1 of 5, and each falls below the significance line its own paper drew. They agree on the verdict and disagree on the digit. They are not independent corroboration: same investigator, same species, same laboratory programme, five years apart. The two assays also differ in vehicle — roughly 10% in propylene glycol in 1989, diluted in mineral oil or gelled in alcohol at 10% in 1984 — and two numbers cannot tell us whether the vehicle, the clay sample or the reading moved between them. Fulton ran no vehicle series on kaolin. No other primary document in the corpus we hold puts a number against it. Morris and Kwan's 1983 rabbit-ear paper, the independent assay on the same scale from a different laboratory, has 32 rows covering lanolins, vegetable oils, esters and surfactants, and no minerals at all. The abstract of Nguyen, Dang and Maibach's 2007 rabbit study names its fourteen test materials; kaolin is not among them.

What the evidence doesn’t tell you

Two rabbit-ear readings from one investigator is what this page rests on, and Fulton undercut that model himself. He called its extreme sensitivity the disadvantage of the method, wrote that "not everything that irritates this model will also irritate human skin", and closed the 1989 paper by calling the survey "not at all definitive but simply designed to stimulate research". Those cautions apply to a 0 exactly as hard as to anyone's 4. A low grade from a test its author called non-definitive is a low grade from a test its author called non-definitive. Neither paper says what kaolin it tested. No geological source, no grade, no purity, no particle size, no processing history. Kaolin is a mined claystone whose composition varies with all of those, and two rows fix none of them. Each grade was also read in one carrier only, and Fulton's own Table II is why that matters. He took one pigment, D&C Red #36, through four carriers and printed four grades: 3 in mineral oil, 2 in pentaerythrital tetra capra/caprylate, 1 in propylene glycol, 0 in PEG 400. That is a different material and it says nothing about kaolin in either direction. What it establishes is that in this assay a solid's grade is a property of the solid and its carrier together — so a 0 read at roughly 10% in propylene glycol is not a vehicle-independent 0, and the 1984 reading was taken in a different carrier. Concentration is a second open edge: the FDA monograph permits kaolin as a skin protectant active at up to 20 percent, and clay masks are built around the powder. What kaolin does above the roughly 10% Fulton used is not something either paper measured. We identified no human comedogenicity study of kaolin. Two recent human studies touch it and neither can attribute anything to it, and they point in opposite directions. Zhang and colleagues reported in Skin Research and Technology in 2023 on a finished clay mask used twice weekly for four weeks by 75 adults with oily or combination skin in Shanghai, and reported improvements in acne-related outcomes, with pore area unchanged; the mask contains kaolin alongside bentonite and several other ingredients, every author is employed by L'Oréal, the product is a L'Oréal brand's, and L'Oréal funded the work. We were unable to obtain the full text and have not read its methods, so we report neither its effect sizes nor its design beyond that. It is a result about a product. Running the other way, Choi and colleagues' 2025 case-control study of 151 people in Guangzhou found powder products an independent risk factor for acne after adjustment, with an odds ratio of 3.47 (95% CI 1.58–7.59) — but it recorded self-reported product categories, not ingredients, it names none, and a questionnaire-based case-control design shows association rather than cause. Neither study is evidence about kaolin. The general gap between an assay and a face applies here too. Draelos and DiNardo's 2006 re-evaluation in the Journal of the American Academy of Dermatology tested finished products on small human upper-back panels and found products testing non-comedogenic while containing ingredients the rabbit assay had flagged. Its methods are paywalled and we have not read them, so we take from it only the general caution, which cuts both ways: nothing on this page says a kaolin-containing product cannot break someone out. Finally, the safety literature is not pore literature, and one part of it cannot be used at all. CIR's 2003 final report concluded that this ingredient group, kaolin included, is safe as used in cosmetic products. That is a safety conclusion and not a comedogenicity finding. The one later document we read on the same ingredient group is the amended assessment of naturally-sourced clays, in the version released on 1 September 2022: every page stamped "Distributed for Comment Only -- Do Not Cite or Quote", the status line reading "Draft Tentative Amended Report for Panel Review", the conclusion section reading "To be determined…". We read that version in August 2026 and take no figure and no finding from it. We have not established what has happened to the assessment since, and we are not going to describe a state we have not read. Across both documents, the words comedogenic and comedogenicity do not appear.

Where you’ll see it

On a label as Kaolin, sometimes written Kaolin Clay. The one concentration figure we can cite to a document rather than to a market impression is regulatory and belongs to drugs, not cosmetics: the FDA's skin protectant monograph permits kaolin as an active ingredient at 4 to 20 percent (21 CFR 347.10(j)). We are not printing a breakdown of cosmetic categories or use levels from the CIR draft described above, because that document instructs readers on every page not to quote it. There may be use figures we have not found, including in any later version of that assessment; we have not searched beyond the documents listed below.

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 primary source for the 0, read here off our own 400dpi visual transcription of Table I rather than through a list quoting it. Method as printed: the test material at roughly 10% in propylene glycol, 1 ml applied once daily to the entire inner surface of one ear of New Zealand albino rabbits, three rabbits per assay, five days a week for two weeks, the opposite untreated ear as control, follicular keratosis judged visually and microscopically with a micrometer. "Kaolin" has its own row, graded 0, with no asterisk and no range, in the powders and thickeners block beside bentonite 0, magnesium aluminum silicate 0, carbomer 940 1, talc 1 and PVP 0. The grade key is on p. 322: 0 to 1 "is not considered significant". Table II of the same paper grades one pigment at 3, 2, 1 and 0 across four vehicles. The paper records no source, grade, particle size or supplier for the kaolin sample, and Fulton describes the whole survey as "not at all definitive but simply designed to stimulate research". A single-investigator rabbit survey, not a clinical trial and not a human result.
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) The earlier rabbit-ear survey from the same investigator, read off a 400dpi render of the journal scan. Method: two New Zealand albino rabbits per test, the material applied to the inner surface of one ear daily for two weeks with the other ear as control, follicular hyperkeratosis graded 0–5 and borderline cases confirmed by microscopic biopsy. Table I prints "Kaolin*" at 1, under "Miscellaneous ingredients", with hectorite also at 1. Two features belong to this paper alone. Its footnote defines the asterisk — materials so marked "were either diluted with mineral oil or incorporated into an alcohol gel at a 10% concentration", unmarked ones being used "as is" if liquid or soft solid — so this is not the "source of raw material" asterisk of the 1989 table, and the two must not be read across. And its key differs: "a minimal grade of 1 to 2 is not considered significant", with 3 or above considered positive, so the same digit does not carry the same meaning in Fulton's two papers. A second reading by the same group, concordant in verdict, and not independent replication.
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) An independent primary rabbit-ear assay on the same 0–5 scale, from a different laboratory, six years before Fulton 1989 — the document that would count as corroboration had it tested this material. It did not. Its 32 rows cover seven lanolins, nine vegetable oils, eleven esters and five surfactants, and include no minerals. Cited for that absence, and as the paper that shows such corroboration is possible and did not happen here: on other materials Morris and Kwan openly contradict Fulton and say so in print.
4. Nguyen SH, Dang TP, Maibach HI. "Comedogenicity in rabbit: some cosmetic ingredients/vehicles." Cutan Ocul Toxicol 26(4):287–292 (2007) The most recent rabbit-ear study in the corpus we hold, graded on a 0–4 scale — a third scale, and one easily misread as Fulton's. We have read its abstract verbatim and not its full text. The abstract names all fourteen test materials, which are esters, fatty alcohols, hydrocarbons, one butter and one surfactant; kaolin is not among them. Cited for that absence.
5. US Geological Survey. Smith DB, Cannon WF, Woodruff LG, Solano F, Ellefsen KJ. "Geochemical and mineralogical maps for soils of the conterminous United States." USGS Scientific Investigations Report 2017-5118, element page "Kaolinite" A federal geological survey publication, cited only for material identity and provenance. It defines kaolinite as a clay mineral, (Al2Si2O5)(OH)4, formed largely by soil processes and most commonly by the chemical breakdown of feldspars, and describes kaolin as "a claystone composed primarily of kaolinite"; it records about 6 million tons mined annually in the United States, mostly in Georgia, for paper coating, ceramics and refractories. It contains no cosmetic, dermatological or comedogenicity data of any kind, and is not used here as evidence about skin.
6. US Food and Drug Administration. 21 CFR 347.10, "Skin protectant active ingredients", Part 347 — Skin Protectant Drug Products for Over-the-Counter Human Use. Subpart B source 68 FR 33377, 4 June 2003. eCFR text read as current to 11 August 2026 The federal drug monograph, cited for one fact only: paragraph (j) lists "Kaolin, 4 to 20 percent" among the permitted skin protectant active ingredients. That is a regulatory concentration range for an over-the-counter drug use, established for a skin-protectant claim. It carries no comedogenicity data, says nothing about follicles, and is not evidence that kaolin is or is not comedogenic at any concentration. It is used here to bound what the assay concentration does and does not cover. The same listing is carried in FDA's OTC monograph system as Monograph M016, section M016.10(j), established by Final Administrative Order OTC000005; we have not read those documents and record the cross-reference unverified by us.
7. Cosmetic Ingredient Review. "Final Report on the Safety Assessment of Aluminum Silicate, Calcium Silicate, Magnesium Aluminum Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium Silicate, Montmorillonite, Pyrophyllite, and Zeolite." Int J Toxicol 22(Suppl 1):37–102 (2003). doi:10.1080/10915810390204890 An expert-panel SAFETY assessment, published in a peer-reviewed toxicology journal in 2003. What we read is the copy reproduced in full inside CIR's 2022 re-review package, read in August 2026. Its conclusion, verbatim, is that the listed ingredients including Kaolin "are safe as used in cosmetic products", and it records that clay silicates "primarily function as adsorbents, opacifiers, and viscosity-increasing agents". It reports no comedone, follicular or acne data for kaolin; the words comedogenic and comedogenicity do not appear in it. Safety is a different question from comedogenicity, and a safe conclusion is not a pore finding. Named separately from the 2022 draft below, because on this site a published report and a document put to the panel are not interchangeable document states.
8. Cosmetic Ingredient Review. "Amended Safety Assessment of Naturally-Sourced Clays as Used in Cosmetics", Draft Tentative Amended Report for Panel Review, release date 1 September 2022, panel meeting 26–27 September 2022 The document as we read it in August 2026, cited to disclose that we read it and to record why we take nothing from it. Every page carries the footer "Distributed for Comment Only -- Do Not Cite or Quote"; its own status line reads "Draft Tentative Amended Report for Panel Review"; its abstract ends "the Panel reviewed all relevant data and concluded that…(to be determined)"; and its conclusion section reads, in full, "To be determined… ". It contains the most recent kaolin use-frequency and concentration tables we could find, and we have deliberately not printed them, because a provisional figure quoted from a document that says not to quote it is a mistake this site has already made and retracted. It contains no comedogenicity assessment of kaolin or of any clay.
9. Zhang X, Zhang Z, Tao H, He X, Hsu K, Wang W, Fang X, Steel A. "Comprehensive assessment of the efficacy and safety of a clay mask in oily and acne skin." Skin Res Technol 29(11):e13513 (2023). doi:10.1111/srt.13513 A study of a FINISHED PRODUCT, not of an ingredient, and the closest thing to human comedone data touching kaolin that we found. A four-week study of a clay mask used twice weekly by 75 adults with oily or combination skin in Shanghai, reporting improvements in acne-related outcomes with pore area unchanged. Industry provenance is total and disclosed here in full: the authors are employed by L'Oréal, the mask is a L'Oréal-owned brand's, and the work was L'Oréal-funded. The mask contains kaolin alongside bentonite, thermal spring water, panthenol and other ingredients, and no per-ingredient concentration or arm is available to us. We could not obtain the full text and have read only the publisher's abstract record, so we do not report its effect sizes, its comparator arrangement or its methods. It cannot support a claim about kaolin in either direction, and it is cited so that a reader who finds it knows exactly what it is.
10. Choi K, Liu H, Zhu Y, Jiang Z, Lu S. "A Case-Control Study Exploring the Association Between Cosmetic Use and Acne Risk: Implications for Prevention and Clinical Practice." Clin Cosmet Investig Dermatol 18:1833–1843 (2025). doi:10.2147/CCID.S533950 A single-centre case-control study of 151 participants at Sun Yat-sen Memorial Hospital, Guangzhou, using a self-administered questionnaire; the authors declare no conflicts. Its endpoint is self-reported product-category use against acne case status — not comedone counts and not ingredients. After adjustment for age, occupation, parental history and milk consumption, powder products remained an independent risk factor, odds ratio 3.47 (95% CI 1.58–7.59). Cited because powders are a category kaolin appears in, and because a page that only reported the study pointing the reassuring way would be doing the thing this site exists to object to. It names no ingredient, cannot attribute the association to any component, and being observational establishes association rather than cause.
11. 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 that tested finished products on small human upper-back panels and found products testing non-comedogenic while containing ingredients the rabbit assay had flagged. Cited narrowly for the single caution that an ingredient's assay result does not transfer cleanly to the formula it ends up in, in either direction. It is not a human re-test of kaolin, it is not a same-substance validation of the rabbit ear against human skin, and its methods are paywalled and unread by us.

Others in the same family

Minerals & pigments 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 minerals & pigments as a family ›

• Bentonite Clear Low
• Iron Oxides Clear Low
• Sodium Chloride Clear Low
• Talc Clear Low
• Titanium Dioxide Clear Low
• Zinc Oxide Clear Low

Last reviewed 2026-08-20 · How we decide

‹ Check a full ingredient list