Is castor oil comedogenic?
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Grades from the 1989 and 1984 rabbit-ear papers, never estimated.
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Educational, not medical advice. Every line below points to the source it comes from.
What the rabbit-ear test found
In Fulton’s rabbit-ear test, castor oil scored 1 out of 5 for comedogenicity, and 0 out of 5 for irritation. On Fulton’s own scale, 0–1 is not significant, 2–3 borderline, and 4–5 positive.
These grades come from rabbit ears: the ingredient applied daily, five days a week for two weeks, usually diluted to 10% in propylene glycol. The grade also shifts with the vehicle and the raw-material source, so one number isn’t the whole story.
Castor oil on the skin
Cleveland Clinic family physician Kevin Hopkins says the main ingredient in castor oil is ricinoleic acid, a fatty acid that can help seal moisture into the skin, which is why it shows up in some moisturizers, cosmetics and deodorants.
Pure castor oil is another matter: “Applying pure castor oil to the skin can cause irritation and allergic reactions like contact dermatitis,” he says. On hair, he says there is no data that castor oil makes it grow, and that it can clog pores on the scalp.
Its relatives on an ingredient list
Castor oil comes in several forms, and they didn’t all grade the same in the rabbit-ear tables:
- Hydrogenated castor oil (castor wax): 1
- PEG-40 castor oil: 0
- PEG-8 castor oil: 1
- Sulfated castor oil, also called Turkey red oil: 3, in the 1984 tables
SourcesFulton JE Jr. Comedogenicity and irritancy of commonly used ingredients in skin care products. J Soc Cosmet Chem. 1989;40(6):321-333.Fulton JE Jr, Pay SR, Fulton JE 3rd. Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear. J Am Acad Dermatol. 1984;10(1):96-105.
Why the number isn’t the whole story
A human-skin model found the rabbit ear more sensitive than human skin: weak rabbit comedogens were judged probably safe, except perhaps for acne-prone people. When finished products were patch-tested on acne-prone backs, products containing comedogenic ingredients were not necessarily comedogenic.
Comedogenic risk also depends on concentration. Ingredients that clog pores when applied neat showed no effect at the under-15% levels typical of face products, and you cannot tell from an ingredient list whether a product will cause acne — only testing the finished product can.
SourcesMills OH Jr, Kligman AM. A human model for assessing comedogenic substances. Arch Dermatol. 1982;118(11):903-905 (abstract).Draelos ZD, DiNardo JC. A re-evaluation of the comedogenicity concept. J Am Acad Dermatol. 2006;54(3):507-512 (abstract).Kligman AM. Petrolatum is not comedogenic in rabbits or humans: a critical reappraisal of the rabbit ear assay and the concept of 'acne cosmetica'. J Soc Cosmet Chem. 1996;47(1):41-48.
What this means for acne-prone skin
The AAD tells acne-prone people to look for products labeled “non-comedogenic” or “won’t clog pores.” But “non-comedogenic” has no FDA definition, so a brand can use the label without any standard test behind it. The honest takeaway: a single comedogenicity number — high or low — is a weak guide. If a product breaks you out, that is the real test.
SourcesAmerican Academy of Dermatology: Acne: Tips for managing.Starzyk T, Aust N, Schur N, Miller R. Comedogenicity in cosmeceuticals: a review of clinical relevance, regulatory gaps, and future directions. JAAD Reviews. 2025;6:78-83 (open access).U.S. Food and Drug Administration: Cosmetics Labeling Claims.
Check a whole product
One ingredient is a start. Paste a full ingredient list to see every rated ingredient on one 0–5 scale, or compare the oils.
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This page answered your question. MySkincare starts from your own skin, and the products you already use.
- 1Scan your face3 photos: front, left profile, right profile.
- 2See your skin scoreFree6 zones scored separately: forehead, eye area, T-zone, both cheeks, chin.
- 3Scan your productsIt reads each ingredient list and says: keep it, watch it or replace it.
- 4Follow your routineMorning and night, checked so your products work together. With reminders.
MySkincare can scan a product’s label and give a verdict for your skin — Keep it, Watch it or Replace it — and tell you if it’s useful with what you already own. It reads what’s on the label; whether a finished product breaks you out still comes down to your own skin.
Questions people ask
Is castor oil bad for acne-prone skin?
In the one lab test behind these ratings, castor oil scored low for clogging pores. For most people it’s unlikely to be a problem — but these rabbit-ear ratings predict real-world breakouts poorly.
Can I put pure castor oil on my face?
Cleveland Clinic’s physician warns that pure castor oil can cause irritation and allergic reactions on the skin. In products, it’s one ingredient among many.
Does castor oil make hair or lashes grow?
For hair, Cleveland Clinic says there is no data showing it promotes growth. We found no source on lashes.
What does a comedogenic rating of 1 mean?
On Fulton’s own scale, 0–1 is not significant, 2–3 borderline, and 4–5 positive. But a human-skin model found the rabbit ear more sensitive than human skin, and products with comedogenic ingredients were not necessarily comedogenic in people.
SourcesFulton JE Jr. Comedogenicity and irritancy of commonly used ingredients in skin care products. J Soc Cosmet Chem. 1989;40(6):321-333.Mills OH Jr, Kligman AM. A human model for assessing comedogenic substances. Arch Dermatol. 1982;118(11):903-905 (abstract).Draelos ZD, DiNardo JC. A re-evaluation of the comedogenicity concept. J Am Acad Dermatol. 2006;54(3):507-512 (abstract).
Can I trust a "non-comedogenic" label?
It is a useful signal — the AAD suggests it for acne-prone skin — but it has no FDA definition, so brands can use it without a standard test. Testing the finished product on your own skin is what settles it.
SourcesAmerican Academy of Dermatology: Acne: Tips for managing.Starzyk T, Aust N, Schur N, Miller R. Comedogenicity in cosmeceuticals: a review of clinical relevance, regulatory gaps, and future directions. JAAD Reviews. 2025;6:78-83 (open access).U.S. Food and Drug Administration: Cosmetics Labeling Claims.
Sources
- Educational content, not medical advice
- Comedogenicity ratings predict real breakouts poorly
Cleveland Clinicclevelandclinic.org
- Cleveland Clinic Health Essentials: castor oil benefits and risks (family physician Kevin Hopkins, MD, December 2023).
Its main ingredient is ricinoleic acid; it can help seal in moisture; pure castor oil on the skin can cause irritation and allergic contact dermatitis; no data that it grows hair; it can clog pores on the scalp.
American Academy of Dermatologyaad.org
US Food and Drug Administrationfda.gov
Studies and other sources
- Fulton JE Jr. Comedogenicity and irritancy of commonly used ingredients in skin care products. J Soc Cosmet Chem. 1989;40(6):321-333.library.scconline.org
- Fulton JE Jr, Pay SR, Fulton JE 3rd. Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear. J Am Acad Dermatol. 1984;10(1):96-105.pubmed.ncbi.nlm.nih.gov
- Mills OH Jr, Kligman AM. A human model for assessing comedogenic substances. Arch Dermatol. 1982;118(11):903-905 (abstract).jamanetwork.com
- Draelos ZD, DiNardo JC. A re-evaluation of the comedogenicity concept. J Am Acad Dermatol. 2006;54(3):507-512 (abstract).jaad.org
- Kligman AM. Petrolatum is not comedogenic in rabbits or humans: a critical reappraisal of the rabbit ear assay and the concept of 'acne cosmetica'. J Soc Cosmet Chem. 1996;47(1):41-48.library.scconline.org
- Starzyk T, Aust N, Schur N, Miller R. Comedogenicity in cosmeceuticals: a review of clinical relevance, regulatory gaps, and future directions. JAAD Reviews. 2025;6:78-83 (open access).jaadreviews.org