Pore clogging ingredient checker
Paste an ingredient list, or type one ingredient. Each comedogenic ingredient on our list of 285 comes back flagged with its rating from 0 to 5 and the source that rating came from, and every other ingredient gets a line on what it does. You get a link to the result to send or keep.
No account, no email, nothing saved. The check runs in your browser. The result link holds the ingredient names itself, so no copy of your list is kept anywhere.
The ratings are a rough guide from older testing, most of it on rabbit ears in the 1970s and 1980s. They say what an ingredient did on its own in that test. They do not predict what a finished product will do on your face, and this page is not medical advice. Where the numbers come from is set out below the tool.
Every rating below names its source and links the papers behind it, so you can check the number instead of taking it on trust. Ingredients with no rating say what they do, from the EU's CosIng database.
Who rated it, ingredient by ingredient
A comedogenic rating is a grade someone gave an ingredient on a rabbit's ear, in a particular study, at a particular strength. Many checkers print the grade alone. Here, for the 50 ingredients people paste most, each result row names the paper, the grade that paper gave, and whether the number on our list sits inside what the papers report.
The two papers are open to read: Fulton 1989, which graded each ingredient at 10 percent in propylene glycol over two weeks, and Morris and Kwan 1983, which mostly tested them undiluted over 14 applications. They do not always agree. Isopropyl myristate is a 5 in Fulton 1989 and a 3 to 4 in Morris and Kwan, who tested it at half strength. Olive oil is a 2 in Fulton 1989 (1 when refined) and a 0 in Morris and Kwan. Seeing both is more useful than one confident number.
On 44 of the ingredients we have traced, the number on our list is higher than every figure in the papers, sodium lauryl sulfate most of all. We have kept the list as published and flagged those rows. Where the list and the research disagree lays all 44 out side by side, and the dataset holds every rating with who rated it, as CSV or JSON.
32 of the 50 trace to at least one of these papers. 18 do not, coconut oil, shea butter and argan oil among them, and their rows say plainly that we could not tie the number to a paper we have read. Fulton's 1984 paper, which many online lists cite, is behind a paywall and we have not read it, so no row claims a figure from it. The rest of the list has not been traced yet, and those rows say that too.
Ingredients with no rating are not left blank. Where the EU's CosIng ingredient database lists what one does, such as a humectant or a preservative, the row says so and links the CosIng entry. Where neither source covers a name, the row says that too.
What a rabbit-ear grade can and cannot tell you
The test puts a raw ingredient on the inside of a rabbit's ear five days a week for two or three weeks and measures how much the follicles plug. That ear reacts more readily than human skin, and Fulton 1989 says so: not everything that irritates the model will irritate a person. The grade is for the ingredient on its own, undiluted or at 10 percent, so it says nothing about the finished formula, how much of the ingredient is in it, 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). Use a grade to decide what to look at more closely. It does not predict your skin, and it is not medical advice.
Share links keep nothing
Some checkers save each analysis on their server to give it a link. Here the link carries the ingredient names itself, after the # in the address, and browsers do not send that part to any server. The link works, and no copy of your list exists anywhere but in the link.
Where the ratings come from
The 0 to 5 scale comes from the rabbit-ear assay: a substance is applied to the inside of a rabbit's ear for a set period and the follicles are examined for plugging. Kligman and Kwong published an improved version of the method in 1979 (Kligman and Kwong, 1979), and Fulton and colleagues used it in 1984 to rate the ingredients, cosmetics and therapeutic products then in general use, one by one (Fulton and colleagues, 1984). Fulton published a longer ingredient table in 1989, and most comedogenic lists online trace back to those two papers.
Our list holds 285 ingredients with a published rating. Where the published ratings disagree about one, the entry shows the range rather than picking a number, and 103 entries do. Each result row above says this, and links to the papers on the ingredient's own page, and for the 50 most pasted ingredients the row names the paper and grade behind the number.
The model has known limits. Mills and Kligman published a human version in 1982, applied to the upper back, because the rabbit result was already known to overstate the risk (Mills and Kligman, 1982). In 2006 Draelos and DiNardo reviewed the whole concept and reported that animal results did not consistently predict human reactions, and that a single ingredient's rating does not establish how a finished product behaves (Draelos and DiNardo, 2006).
How to read a result
Results sort highest rating first. The scale is the one the list publishes, and the gloss on each band is this site's own.
| Rating | What it means |
|---|---|
| 0 Non-comedogenic | No increase in follicle plugging in the rabbit-ear test. |
| 1–2 Low risk | Little plugging in the rabbit-ear test. Fulton 1989 counts 0 to 1 as not significant and 2 as borderline. |
| 3 Moderate risk | Borderline plugging in the rabbit-ear test. Worth a look in a leave-on product. |
| 4–5 High risk | Clear plugging in the rabbit-ear test. The first band to check in a leave-on product. |
| ? Not on our list | No published rating is held here. That is not the same as a 0. |
- Position on the label matters. Ingredients are listed in descending order of amount, so a 4 near the top of a list is a different thing from the same 4 in last place at well under one percent (FDA labeling guide).
- Leave-on and rinse-off differ. A cleanser is on the skin for seconds; a moisturizer or foundation for hours. The ratings were measured by applying the substance to skin every day for about two weeks, which is closer to the second case than the first.
- Not on the list is an open question. It means the sources did not rate the ingredient, and why that is different from safe has its own page. 173 of the 285 entries sit in the high band.
- Nobody tested the product. The checker reads names. It does not know concentrations, and it has not tested anything. A dermatologist can look at your skin; this page cannot.
The list behind the checker
The full pore-clogging ingredients list shows all 285 as a table with the family and what each one does, and the ratings grouped by family sorts the oils, butters, esters and the rest. Every entry has its own page with the rating, what it means in practice, and the papers it rests on.
The ingredient checker page carries the same tool with the whole list printed beneath it. If the bumps are small, itchy and all the same size, the fungal acne checker reads a label against a different body of research. And what non-comedogenic means on a label, and what it does not, has its own page.
Common questions
Is a pore clogging checker the same as a comedogenic checker?
Yes. Comedogenic is the dermatology word for pore clogging: a comedogenic ingredient tends to cause comedones, the blackheads and whiteheads that form when a follicle opening is blocked. This checker reads a label against the published comedogenic ratings, so it answers both names.
Where do the ratings come from?
From rabbit-ear studies published between the 1970s and 1990s. For the 50 ingredients people paste most, we read the rating tables of Fulton 1989 and Morris and Kwan 1983 and show each paper's grade on the result row. 32 trace to at least one of them; 18 do not, and the row says so. Where published ratings disagree, our list shows the range, and 103 entries do.
Do I need an account or an email address?
No. The list is built into the page and the matching runs in your browser. Nothing you paste is sent anywhere, and there is no sign-up, no email gate and nothing to buy.
Can I share or save a result?
Yes. After a check, the page gives you a link to that result. The link holds the ingredient names, after the # in the address, which browsers do not send to the server, so nothing is stored on this site. Opening it checks the list again against the ratings as they are that day.
Why is an ingredient not on the list?
Because no published comedogenic rating for it is held here. Water, glycerin, most silicones and most preservatives come back as not on the list. That is different from a rating of 0: it means the question was not answered in the sources, not that the answer is no.
Does a clean result mean the product will not break me out?
No. A rating belongs to one ingredient tested on its own, mostly on rabbit ears, and a 2006 review found those results did not reliably predict what happened on human skin. Concentration, the rest of the formula and your own skin all change the outcome. Treat a result as a reason to look closer, and ask a dermatologist about persistent breakouts.
What this tool is built on
- Kligman AM, Kwong T. “An improved rabbit ear model for assessing comedogenic substances.” British Journal of Dermatology, June 1979;100(6):699–702. (opens in a new tab) The rabbit-ear assay that produced most of the 0–5 numbers still quoted today.
- 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.
- 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.
- Mills OH Jr, Kligman AM. “A human model for assessing comedogenic substances.” Archives of Dermatology, November 1982;118(11):903–905. (opens in a new tab) The human back-skin model, developed because the rabbit ear was known to overstate the risk.
- 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.
- U.S. Food and Drug Administration, “Cosmetics Labeling Guide”. (opens in a new tab) Ingredients must be listed in descending order of predominance; those at 1 percent or less may follow in any order, and colour additives may be listed last in any order.
- U.S. Food and Drug Administration, “Cosmetics Labeling Claims”. (opens in a new tab) States that the FDA does not keep a list of approved or accepted cosmetic claims; a label must simply be truthful and not misleading. There is no FDA definition of “non-comedogenic” for a brand to meet.
- European Commission, “CosIng: Cosmetic ingredient database”. (opens in a new tab) The EU database of cosmetic ingredients. For each INCI name it lists the functions the ingredient serves in a product, such as humectant, emollient or preservative. It holds no comedogenic ratings.