Comedogenic Ratings Checked: Does an Oil Clog Pores?
Comedogenic ratings of 0 to 5 are everywhere online. See where they come from (rabbit ears), what human studies found, and why a number cannot tell you if an oil will clog your pores.
Content last updated . This page has not been medically reviewed.
You have probably seen a chart that gives every oil and butter a "comedogenic rating" from 0 to 5. A low number is said to be safe for your pores, and a high number is said to cause breakouts. It looks neat and scientific. This page checks where those numbers come from and what the research really says. The short answer: the numbers are a rough lab starting point, not a promise about what an oil will do on your face. We do not reprint a rating table here, because a table would look more certain than the science is.
Read this first
- "Comedogenic" means "tends to form comedones", which are blocked pores (blackheads and whiteheads). The 0 to 5 lists were built mostly from rabbit-ear tests and older ingredient lists. [1][2]
- A 2006 human study found that finished products made with "comedogenic" ingredients were not necessarily comedogenic. [3]
- An early human-skin model agreed with the rabbit test for strong comedogens, but found the rabbit ear more sensitive. Its authors said substances that are only weak in rabbits are probably safe for most people, though acne-prone people may still react. [2]
- We found no controlled trial that tested a popular oil against a rating-based claim. The one jojoba study we read had no control group. [11]
- "Non-comedogenic" on a label is not a guarantee. FDA does not approve cosmetic claims before sale, and we found no federal definition of the term in the FDA pages we read. [9]
- If you break out after a new oil, stop using it. Your own skin is the best test. See patch testing.
Where the 0 to 5 numbers come from
The idea of "acne cosmetica", acne caused by cosmetics, led researchers to look for a quick test of which ingredients plug pores. The test used most was the rabbit ear assay. An ingredient is put on the inside of a rabbit's ear for a couple of weeks, and the follicles are checked for buildup. Researchers published results for many ingredients and products this way. One example is a 1984 study in the Journal of the American Academy of Dermatology (Fulton and colleagues), which reported that several ingredients and some dermatology products were comedogenic in rabbits. [1] A later rabbit study of 14 cosmetic ingredients classed cocoa butter, petrolatum and others as comedogenic, and its authors listed factors that affect how well results carry over to people. [5]Ingredient lists then gave each material a 0 to 5 score. We could not find one single official source for the "0 to 5" scale that all websites copy, so charts you see online may differ from each other and from the original papers.
Note: the rabbit studies tested single raw ingredients, often under a covering, and rabbit ears are not human faces. Skin type, hormones, oil production and the other ingredients in a product all differ in people.
The human tests
Researchers built a human version. In 1982, Mills and Kligman applied test materials under cover to the upper backs of young men with large follicles for one month, then used a cyanoacrylate glue "biopsy" to pull out follicle contents. Substances rated moderate to strong in rabbits did make comedones in people. The rabbit test was the more sensitive of the two. [2]Later human studies used the same back-skin method and gave a mixed picture.
| Study | Who and how long | What was found | How strong |
|---|---|---|---|
| Draelos and DiNardo, 2006 [3] | 6 volunteers prone to comedones; finished cosmetic products on the upper back, 3 times a week for 4 weeks | Finished products containing comedogenic ingredients were not necessarily comedogenic. The authors said only a limited number of products were tested. | Very small |
| Baek et al., 2022 [6] | 6 people; cocoa butter patches on the upper back, checked at 2 and 4 weeks | Cocoa butter sites showed more microcomedone changes than untreated skin. | Very small; confirms one butter on back skin only |
| Waranuch et al., 2021 [7] | 15 healthy men enrolled, 12 analyzed; patches on the upper back for 4 weeks, with a known pore-clogging chemical as a positive control | The positive control raised microcomedone counts about 365%. The tested vitamin E products (which also contained lanolin, kernel oil, avocado oil and sunflower oil) raised counts by less than 50%, and the authors called them non-comedogenic. | Small; tested finished products, not single oils |
| Baek et al., 2016 [4] | 66 women with mild to moderate facial acne | Comedones, oil and other skin measures varied between the face and back, and the authors suggested testing both sites depending on the material. | One study, small differences between sites |
The picture: lab tests can flag some ingredients, but small human studies show that the same ingredient may behave differently once it is in a finished product, and that the test site matters.
What reviews and commentary say
A review of how claims are tested (Weiss and Caswell, 2017) describes two methods for supporting a "non-comedogenic" claim: a low-cost human back-skin model derived from Mills and Kligman, and a clinical trial that costs more and is considered the more reliable standard. [8] A short 2018 JAMA Dermatology letter looked at comedogenicity labeling for clinicians; we could not read its text, only the title and record, so we do not summarize its findings. [10]Taken together, the papers we read agree that ratings come from experimental models with known limits. We did not find a source we read that says the lists reliably predict acne in people.
Oils and acne: what has actually been tested
Proper evidence not found, in the sources we read, for most popular oils (coconut, argan, rosehip, olive and others) causing or preventing acne in controlled human trials.- Jojoba: A 2012 pilot study had 194 mostly female adults with lesioned skin or mild acne use clay and jojoba oil masks 2 to 3 times a week for 6 weeks. Among the 133 with full lesion counts, total lesions fell by about 54%. [11] It had no control group, and a clay mask was part of the treatment, so we cannot say what jojoba did. Studied does not mean it works.
- Tea tree is an essential oil, not a fixed oil, so it is not covered here. See essential oils for skin, acne and eczema.
A 2025 case-control study of 151 people found that moisturizers and facial cleansers with comedogenic ingredients were linked to acne in that group, and that using more product was linked to higher risk. [12] This kind of study shows associations, not cause, and it did not test single oils in the sources we read.
Two ideas about fatty acids (hypotheses, not proof)
You may read that oils high in linoleic acid are "good for acne" and oils high in oleic acid are "bad". This comes from a 1986 paper by Downing and colleagues. They noted that people with acne have more sebum but less linoleic acid in their skin surface fats, and they proposed that low linoleic acid inside the follicle could lead to excess skin-cell buildup. [13] They described this as an idea that fits the data, not a tested treatment. We did not find a controlled trial in the sources we read showing that putting a high-linoleic oil on the skin treats acne, or that oleic acid oils cause it. Treat these as hypotheses.Why formulation and amount matter
A "rating" is for one ingredient. A real product has waxes, emulsifiers, other oils and preservatives, and the same oil may be used at 2% or at 100%. The 2006 study above is the best-known example: products with comedogenic ingredients did not necessarily act comedogenic. [3] How much you put on matters too. In the 2025 case-control study, larger amounts of product were linked to higher acne risk. [12] Pure oils used as a face oil, a cleansing balm (see the oil cleansing method) and a hair product that runs onto your forehead are three different exposures.What to do with this in real life
- Some people with acne-prone skin break out on rich oils. Others use the same oil for years without trouble. We found no source that lets us predict which group you are in.
- If you want to try a new oil, test a small area first and introduce one product at a time, so that you know which product caused a change. See patch testing natural oils and butters.
- Persistent or painful acne is a medical problem. See acne and ask a doctor or dermatologist.
Claims checked
| Claim | What the sources say |
|---|---|
| "Coconut oil is a 4, so it will always cause acne." | The number comes from lists, not from a single standard. We found no source we read that tested coconut oil for pore blockage in people. [3] |
| "A low rating means safe for acne." | A rating predicts neither direction reliably. The one finished-product study found "comedogenic" ingredients did not necessarily clog pores. [3] |
| "Rabbit tests prove it." | Rabbit ears were found more sensitive than human skin, and weak rabbit results are probably safe for most people. [2] |
| "Non-comedogenic means tested and guaranteed." | AAD pages describe it as a "won't clog pores" label. [14] FDA does not approve cosmetic claims before sale, and the FDA pages we read do not define "non-comedogenic". [9] The 2017 review lists human models and trials as ways to support the claim. [8] |
| "Jojoba is like your skin's own oil and treats acne." | Only an uncontrolled clay-and-jojoba mask study was found. [11] |
| "Linoleic acid oils fix acne." | A 1986 hypothesis; not shown in a trial we read. [13] |
Related pages
Frequently asked questions
What does comedogenic mean?
It means something tends to cause comedones, the blocked pores called blackheads and whiteheads. [3]
Where do comedogenic ratings come from?
Mostly from rabbit-ear studies and older ingredient lists, plus small human back-skin tests. We could not find one official source of the 0 to 5 scale. [1][2][5]
Can I trust a low comedogenic rating?
Not as a promise. Small human studies suggest a finished product can behave differently from its ingredients, and acne-prone people may still react. [2][3]
Does "non-comedogenic" on a label mean it is tested?
Not necessarily. FDA does not approve cosmetic claims before sale, and the FDA pages we read do not define the term. [9]
Which oil is best for acne-prone skin?
Proper evidence not found. The one jojoba study we read had no control group. [11] Introduce one product at a time and stop it if you break out.
References
- Fulton JE Jr, Pay SR, Fulton JE 3rd, J Am Acad Dermatol 1984;10(1):96-105, Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear (PMID 6229554). Read 2026-10-24 (record via Europe PMC).
- Mills OH Jr, Kligman AM, Arch Dermatol 1982;118(11):903-905, A human model for assessing comedogenic substances (PMID 7138047). Read 2026-10-24 (record via Europe PMC).
- Draelos ZD, DiNardo JC, J Am Acad Dermatol 2006;54(3):507-512, A re-evaluation of the comedogenicity concept (PMID 16488305). Read 2026-10-24 (record via Europe PMC).
- Baek JH et al., Skin Res Technol 2016;22(2):164-169, Analysis of comedone, sebum and porphyrin on the face and body for comedogenicity assay (PMID 26094640). Read 2026-10-24.
- Nguyen SH, Dang TP, Maibach HI, Cutan Ocul Toxicol 2007;26(4):287-292, Comedogenicity in rabbit: some cosmetic ingredients/vehicles (PMID 18058303). Read 2026-10-24.
- Baek JH et al., J Cosmet Dermatol 2022;21(7):3016-3021, Early detection of microcomedones induced by cocoa butter using reflectance confocal microscopy (PMID 34632684). Read 2026-10-24.
- Waranuch N et al., Contemp Clin Trials Commun 2021;23:100834, Safety assessment on comedogenicity of dermatological products containing d-alpha tocopheryl acetate in Asian subjects (PMID 34471722). Read 2026-10-24.
- Weiss C, Caswell M, J Cosmet Sci 2017;68(4):253-256, Non-comedogenic and non-acnegenic claim substantiation (PMID 29616616). Read 2026-10-24 (record via Europe PMC).
- US Food and Drug Administration, Cosmetics Labeling Claims and Hypoallergenic Cosmetics. Read 2026-10-24. Neither page mentions "non-comedogenic".
- Maarouf M, Saberian C, Shi VY, JAMA Dermatol 2018;154(10):1131-1132, Myths, Truths, and Clinical Relevance of Comedogenicity Product Labeling (PMID 29998304). Bibliographic record only; no abstract or full text read.
- Meier L, Stange R, Michalsen A, Uehleke B, Forsch Komplementmed 2012;19(2):75-79, Clay jojoba oil facial mask for lesioned skin and mild acne: a prospective, observational pilot study (PMID 22585103). Read 2026-10-24.
- Choi K et al., Clin Cosmet Investig Dermatol 2025;18:1833-1843, Association between cosmetic use and acne risk: a case-control study (PMID 40765696). Read 2026-10-24.
- Downing DT, Stewart ME, Wertz PW, Strauss JS, J Am Acad Dermatol 1986;14(2 Pt 1):221-225, Essential fatty acids and acne (PMID 2936775). Read 2026-10-24.
- American Academy of Dermatology, What can treat large facial pores?. Read 2026-10-24.