Where the comedogenic list and the research disagree

For 44 common ingredients, the popular pore-clogging list this site carries gives a higher number than any figure in the two rabbit-ear studies we have read in full. Sodium lauryl sulfate is the starkest: the list says 5, and the study that graded it found no plugging at all.

We have not changed the list. It is a published reference that many checkers use, and swapping in our own numbers would hide the disagreement. Instead, every one of these rows is flagged in the pore clogging ingredient checker and on the ingredient's own page, with the list's number and the papers' figures side by side.

The 44, side by side

Fulton 1989 tested each ingredient at 10 percent in propylene glycol for two weeks. Morris and Kwan 1983 tested them undiluted unless the table says otherwise, over 14 applications. Both graded 0 to 5. Largest gap first.

Ingredient	Our list	Fulton 1989	Morris and Kwan 1983	What to take from it
Sodium Lauryl Sulfate	5 High risk	Fulton 1989: not tested	Morris and Kwan 1983: 0 (10% aqueous); 0 (5% aqueous)	The documented problem with SLS is irritation: it is the standard substance used to irritate skin in studies. Morris and Kwan found no plugging at 5 or 10 percent. Fulton 1976 called it comedogenic, but the abstract gives no grade, and we have not read the paper.
Sunflower Oil	1–5 High risk	Fulton 1989: 0	Morris and Kwan 1983: not tested	The one paper that tested it found no plugging. Sunflower oil is sold in high-linoleic and high-oleic types under one name, and the papers do not say which they used.
Acetylated Lanolin	4 High risk	Fulton 1989: 0	Morris and Kwan 1983: not tested	Fulton graded acetylated lanolin 0. He found the acetylated lanolin alcohol, a different ingredient, comedogenic, and put that down to a cetyl acetate additive rather than the lanolin.
Anhydrous Lanolin	5 High risk	Fulton 1989: 0 to 1, varying with the supplier	Morris and Kwan 1983: not tested	The widest gap in the lanolins. Fulton graded anhydrous lanolin 0 to 1 and noted the result depended on the supplier; the list says 5. Lanolin is in a great many lip balms, ointments and creams, so this one matters.
Isocetyl Stearate	5 High risk	Fulton 1989: not tested	Morris and Kwan 1983: 0 to 1	Morris and Kwan graded it 0 to 1. The list says 5, the top of the scale.
Apricot Kernel Oil	2–5 High risk	Fulton 1989: 2, or 1 for the refined oil	Morris and Kwan 1983: not tested	Fulton gave it 2, or 1 refined. The list’s range runs to 5.
Ascorbyl Palmitate	2–5 High risk	Fulton 1989: 2	Morris and Kwan 1983: not tested	Fulton gives 2. The list’s range runs much higher, and we could not find where the upper figures came from.
Groundnut Oil	5 High risk	Fulton 1989: 2 (groundnut oil is the same oil)	Morris and Kwan 1983: not tested	Groundnut oil is peanut oil. Fulton gives peanut oil 2, and our own list rates the same oil 2 to 3 under the name peanut oil and 5 under this one.
Hexadecyl Alcohol	5 High risk	Fulton 1989: 2 (the same substance)	Morris and Kwan 1983: not tested	Hexadecyl alcohol is another name for cetyl alcohol. Fulton gives cetyl alcohol 2, and our own list rates the same substance 2 under that name and 5 under this one.
Olive Oil	3–5 High risk	Fulton 1989: 2, or 1 for the refined oil	Morris and Kwan 1983: 0	Both papers put it low, and refined olive oil lower still. Nothing we read supports the 4 or 5.
PG Caprylate	3–5 High risk	Fulton 1989: 2	Morris and Kwan 1983: not tested	Fulton gives 2. The list’s range runs to 5.
Avocado Oil	3–5 High risk	Fulton 1989: 3, or 2 for the refined oil	Morris and Kwan 1983: 0	The papers disagree with each other too: Fulton found a 3 for the crude oil, Morris and Kwan found no plugging. The 4 and 5 are not in either.
Behenic Acid	2 Low risk	Fulton 1989: 0	Morris and Kwan 1983: not tested	Fulton gives 0. He found medium-chain fatty acids more potent than short or long ones, and behenic acid is a long one. The list says 2.
Emulsifying Wax NF	2 Low risk	Fulton 1989: 0	Morris and Kwan 1983: not tested	Fulton gives 0. The list says 2.
Laneth-10	2–4 High risk	Fulton 1989: 2	Morris and Kwan 1983: not tested	Fulton 1989 gave it 2. The list’s 4 is above every figure we read.
Lanolin Alcohol	2–4 High risk	Fulton 1989: 0 to 2, varying with the supplier	Morris and Kwan 1983: 1 to 2 (30% in mineral oil)	Both papers stop at 2, and Fulton notes the result depended on the supplier. Morris and Kwan tested it at 30 percent in mineral oil.
Lanolin Wax	3 Moderate risk	Fulton 1989: 1	Morris and Kwan 1983: not tested	Fulton gives 1. The list’s 3 is two steps above.
Oleth-10	2–4 High risk	Fulton 1989: 2	Morris and Kwan 1983: not tested	Fulton 1989 gave it 2. The list’s 4 is above every figure we read.
Peach Kernel Oil	2–4 High risk	Fulton 1989: not tested	Morris and Kwan 1983: 2	Morris and Kwan 1983 gave it 2. The list’s 4 is above every figure we read.
PG Dipelargonate	2–4 High risk	Fulton 1989: 2	Morris and Kwan 1983: not tested	Fulton 1989 gave it 2. The list’s 4 is above every figure we read.
PPG 12 PEG 65 Lanolin Oil	2–4 High risk	Fulton 1989: 2	Morris and Kwan 1983: not tested	Fulton 1989 gave it 2. The list’s 4 is above every figure we read.
Sesame Oil	3–5 High risk	Fulton 1989: 3, or 1 for the refined oil	Morris and Kwan 1983: 1 (Lipoval SES)	Fulton gave crude sesame oil 3 and refined 1; Morris and Kwan gave it 1. Nothing we read supports the 4 or 5.
Soybean Oil	3–5 High risk	Fulton 1989: 3	Morris and Kwan 1983: not tested	Fulton’s 3 matches the bottom of the list’s range. The 4 and 5 are not in the papers we read.
Sweet Almond Oil	3–5 High risk	Fulton 1989: 2, or 1 for the refined oil	Morris and Kwan 1983: 3	Another case where the two papers differ, 2 against 3. Neither reaches the list’s top figure.
Babassu Oil	2 Low risk	Fulton 1989: 1	Morris and Kwan 1983: not tested	Fulton 1989 gave it 1. The list’s 2 is above every figure we read.
Butyl Stearate	3–4 High risk	Fulton 1989: 3	Morris and Kwan 1983: not tested	Fulton 1989 gave it 3. The list’s 4 is above every figure we read.
Castor Oil	1–2 Low risk	Fulton 1989: 1	Morris and Kwan 1983: 0 to 1	Both papers grade it low. The list’s 2 is one step above.
Chaulmoogra Oil	2 Low risk	Fulton 1989: 1	Morris and Kwan 1983: not tested	Fulton gives 1. The list’s 2 is one step above.
Di (2-ethylhexyl) Succinate	2–3 Moderate risk	Fulton 1989: 2 (2 ethylhexyl)	Morris and Kwan 1983: not tested	Fulton 1989 gave it 2 (2 ethylhexyl). The list’s 3 is above every figure we read.
Ethylhexyl Pelargonate	2–3 Moderate risk	Fulton 1989: 2	Morris and Kwan 1983: not tested	Fulton 1989 gave it 2. The list’s 3 is above every figure we read.
Grapeseed Oil	1–4 High risk	Fulton 1989: not tested	Morris and Kwan 1983: 2 to 3	Morris and Kwan gave it 2 to 3. The list’s range runs to 4.
Hydrogenated Castor Oil	2 Low risk	Fulton 1989: 1	Morris and Kwan 1983: not tested	Fulton 1989 gave it 1. The list’s 2 is above every figure we read.
Isodecyl Oleate	3–4 High risk	Fulton 1989: 2 to 3, varying with the supplier	Morris and Kwan 1983: 1	Fulton 1989 gave it 2 to 3, varying with the supplier; Morris and Kwan 1983 gave it 1. The list’s 4 is above every figure we read.
Isopropyl Lanolate	4 High risk	Fulton 1989: not tested	Morris and Kwan 1983: 3	Morris and Kwan gave it 3. The list’s 4 is one step above.
Lanolic Acid	4–5 High risk	Fulton 1989: not tested	Morris and Kwan 1983: 4 (50% in mineral oil)	Morris and Kwan 1983 gave it 4 (50% in mineral oil). The list’s 5 is above every figure we read.
Mineral Oil	1–3 Moderate risk	Fulton 1989: 0 to 2	Morris and Kwan 1983: not tested	Fulton gives 0 to 2. A 2005 review of the rabbit and human data concluded that cosmetic-grade mineral oil is unlikely to be comedogenic in people.
Palmitic Acid	2–3 Moderate risk	Fulton 1989: 2	Morris and Kwan 1983: not tested	Fulton gives 2. The list’s 3 is one step above.
Peanut Oil	2–3 Moderate risk	Fulton 1989: 2	Morris and Kwan 1983: not tested	Fulton 1989 gave it 2. The list’s 3 is above every figure we read.
PEG 16 Lanolin	4–5 High risk	Fulton 1989: 4 (Solulan 16)	Morris and Kwan 1983: not tested	Fulton 1989 gave it 4 (Solulan 16). The list’s 5 is above every figure we read.
PEG 8 Castor Oil	2 Low risk	Fulton 1989: 1	Morris and Kwan 1983: not tested	Fulton 1989 gave it 1. The list’s 2 is above every figure we read.
PPG 10 Cetyl Ether	3–4 High risk	Fulton 1989: 3	Morris and Kwan 1983: not tested	Fulton 1989 gave it 3. The list’s 4 is above every figure we read.
PPG 2 Myristyl Propionate	3–4 High risk	Fulton 1989: 3	Morris and Kwan 1983: not tested	Fulton 1989 gave it 3. The list’s 4 is above every figure we read.
Propylene Glycol Monostearate	4 High risk	Fulton 1989: 0 to 3 (the same substance)	Morris and Kwan 1983: not tested	The same ingredient as PG monostearate, which Fulton graded 0 to 3. Our own list rates it 3 under that name and 4 under this one.
Sorbitan Isostearate	2–3 Moderate risk	Fulton 1989: 1 to 2, varying with the supplier	Morris and Kwan 1983: not tested	Fulton gives 1 to 2, varying with the supplier. The list’s 3 is one step above.

A figure like "2, or 1 for the refined oil" is Fulton's result for the crude oil and then the refined one. "Varying with the supplier" is Fulton's own note that the result depended on where the raw material came from.

How a list drifts from the research

A comedogenic list is a compilation. Its numbers come from several rabbit-ear studies run over two decades, and those studies did not test things the same way. Fulton diluted ingredients to 10 percent; Morris and Kwan mostly applied them neat. Some used crude oils and some refined. Fulton found that the same ingredient graded differently depending on the supplier. Morris and Kwan wrote their paper because investigators were already getting different answers.

When those results are merged, the natural move is to keep the widest range, or the highest figure as the cautious one. Some figures come from papers that are hard to get hold of, such as Fulton's 1984 table, which is behind a paywall and which we have not read. Lists are then copied from site to site, and the source of a number gets lost along the way. None of that needs anyone to have acted in bad faith. It is what happens to a number that is copied more often than it is checked.

So a list figure higher than the papers we read may still come from a real study we have not seen. What we can say is that it is not in these two, and that is worth knowing before you avoid an ingredient because of it.

What any of these numbers can tell you

Every figure on this page, the list's and the papers', is for a raw ingredient put on the inside of a rabbit's ear five days a week for two or three weeks. That ear reacts more readily than human skin, and Fulton 1989 says as much. The grade says nothing about a finished product, how much of the ingredient it holds, or what the rest of the formula does. A 2006 review found the animal results did not reliably predict reactions on people (Draelos and DiNardo, 2006).

Read a grade as a reason to look closer at a label, and a disagreement like the ones above as a reason not to treat any single number as settled. None of this is medical advice. If breakouts keep coming, a dermatologist can look at your skin.

How these figures were checked

Both papers are open in the Society of Cosmetic Chemists library. Every figure here was read twice: first off the page images, then again from the PDF's own text, matching each ingredient to its grade by position on the page. One table in Morris and Kwan is printed sideways as a picture with no text, so it was re-read from a zoomed render, using its supplier and fatty-acid columns to confirm each row. No figure changed between the two readings.

The papers were read for the 50 ingredients people paste most, and for 133 more whose descriptions on this site needed correcting. For each of them the ingredient's own page and the checker show who rated it. The rest of the ingredient list has not been traced yet. Where a number could not be traced to either paper, the row says that too. Every row, traced or not, is in the comedogenic ratings dataset, free to download as CSV or JSON. The full method is on the checker page.

Common questions

Is sodium lauryl sulfate comedogenic?

The evidence we have read says it has not been shown to be. Morris and Kwan graded it 0 at 5 and 10 percent on the rabbit ear, and a 2007 review did not list it among the materials found positive. It is a well documented skin irritant, which is a real reason people react to it. The popular list rates it 5.

Why does the list give higher numbers than the studies?

Lists like this are compiled from several studies that used different strengths, carriers, suppliers and grading. Taking the highest figure any source reported, or carrying a figure from a study that is hard to get hold of, pushes numbers up over time. That is drift, and it does not need anyone to have acted in bad faith.

Why not change the numbers on your list?

Because the list is a published artefact that many people and checkers use, and quietly swapping in our own figures would hide the disagreement. Showing the list and the papers side by side lets you see both and decide.

Does a low rating mean an ingredient will not break me out?

No. Every figure here is for the raw ingredient on a rabbit’s ear, which reacts more readily than human skin. A grade says nothing about a finished product, how much of the ingredient it holds, or the rest of the formula. It is a rough guide, and this page is not medical advice.

Sources used on this page

Fulton JE Jr. “Comedogenicity and irritancy of commonly used ingredients in skin care products.” Journal of the Society of Cosmetic Chemists, November/December 1989;40(6):321–333. (opens in a new tab) Rabbit ear. Each ingredient at 10 percent in propylene glycol unless stated, applied five days a week for two weeks, and graded 0 to 5 from the width of the follicles, measured by micrometer and under the microscope. The paper counts 0 to 1 as not significant, 2 to 3 as borderline and 4 to 5 as positive. Some grades depended on the supplier of the raw material, and some oils were also tested refined.
Morris WE, Kwan SC. “Use of the rabbit ear model in evaluating the comedogenic potential of cosmetic ingredients.” Journal of the Society of Cosmetic Chemists, August 1983;34(5):215–225. (opens in a new tab) Rabbit ear canal, at the Revlon Research Center. Each material applied undiluted unless stated, once a day five days a week for 14 applications, and graded 0 to 5 by microscope only. The authors set out to recheck earlier results because investigators disagreed.
Fulton JE Jr, Bradley S, Aqundez A, Black T. “Non-comedogenic cosmetics.” Cutis, February 1976;17(2):344–351. (opens in a new tab) Rabbit ear. Read at abstract level: it names butyl stearate, isopropyl myristate and sodium lauryl sulfate among the emulsifiers found comedogenic.
Nguyen SH, Dang TP, Maibach HI. “Comedogenicity in rabbit: some cosmetic ingredients/vehicles.” Cutaneous and Ocular Toxicology, 2007;26(4):287–292. (opens in a new tab) Rabbit ear. Read at abstract level: of fourteen materials, the first nine named (isopropyl palmitate, isopropyl myristate, butyl stearate, isopropyl isostearate, decyl oleate, isostearyl neopentanoate, isocetyl stearate, myristyl myristate and cocoa butter) were deemed positive; cetyl alcohol, paraffin, stearyl alcohol, sodium lauryl sulfate and petrolatum were not among them.
Lee CH, Maibach HI. “The sodium lauryl sulfate model: an overview.” Contact Dermatitis, July 1995;33(1):1–7. (opens in a new tab) Sodium lauryl sulfate is the most widely used substance for causing acute and cumulative irritation in skin studies. The review sets out decades of that work.
DiNardo JC. “Is mineral oil comedogenic?” Journal of Cosmetic Dermatology, January 2005;4(1):2–3. doi:10.1111/j.1473-2165.2005.00150.x (opens in a new tab) A short commentary reviewing the rabbit-ear and human data on mineral oil, which concludes that cosmetic-grade mineral oil is unlikely to be comedogenic in people.
Fulton JE Jr, Pay SR, Fulton JE 3rd. “Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear.” Journal of the American Academy of Dermatology, January 1984;10(1):96–105. (opens in a new tab) The published ingredient-by-ingredient ratings that most comedogenic lists, including this one, trace back to.
Draelos ZD, DiNardo JC. “A re-evaluation of the comedogenicity concept.” Journal of the American Academy of Dermatology, March 2006;54(3):507–512. doi:10.1016/j.jaad.2005.11.1058 (opens in a new tab) Found that animal-model results did not reliably predict what happened on human skin, and that a rating for a single ingredient does not tell you how a finished product will behave.