About 90% ricinoleic acid
ReviewRicinoleic acid, a hydroxylated monounsaturated fatty acid, makes up about 90% of the fatty acids in the oil1.
Castor oil
Castor oil is the fixed oil extracted from the seeds of Ricinus communis4. It is made of about 90% ricinoleic acid1 and contains no ricin2. The CIR panel judges it safe in cosmetics3. On hair, the evidence is weak and shows no growth5.
Castor oil at a glance
Entry from our cosmetic ingredient glossary. Regulatory data from the European Commission's CosIng database4, safety according to the CIR expert panel3. Copy the identifiers in one click for your files.
- INCI name
- RICINUS COMMUNIS SEED OIL
- Other names
- Castor oilCastor oil; ricini oleum (European Pharmacopoeia)4
- CAS number
- 8001-79-4
- EC number
- 232-293-8
- Botanical origin
- Castor plant (Euphorbiaceae)Fixed oil from the seeds of Ricinus communis4; plant native to northeastern Africa and India1
- Main fatty acid
- Ricinoleic acidAbout 90% of the fatty acids1
- CosIng functions
- Skin conditioningAlso listed as a perfuming agent4
- EU status
- No restrictionNot listed in the annexes of Regulation (EC) 1223/20094
- Allergen to declare
- NoRicin, the seed toxin, does not pass into the oil2
What the research says
Each result shows the protocol and the level of evidence. The higher the level, the better the result carries over to a finished formula.
Clinical trialReview or consensusLaboratory
Composition and qualityChemistry
Cosmetic castor oils sometimes cut with other oils
LaboratoryThree of the nine samples contained little ricinoleic acid, a sign of blending with other vegetable oils. Measuring the fatty acid profile is a useful quality check at purchase10.
Scalp and hairHaircare
Shine: weak evidence. Growth: no solid evidence
ReviewThe evidence for improved hair shine is weaker than for coconut oil, and there is no solid evidence of an effect on growth5.
Growth hypothesis: computer modeling only
LaboratoryComputer modeling predicts that ricinoleic acid could bind to an enzyme linked to hair shedding. This is a prediction, not a measurement: the authors describe leads for future studies7. No human trial is cited here.
Studies on hair oils remain scarce and animal-based
ReviewThe authors note that most studies on hair oils were run on mice and that more research is needed6.
A rare risk: tangled hair
Case reportA case of acute, irreversible felting of long hair was described after both oils were applied after washing. The authors point to the viscosity of castor oil9.
Skin and bodySkincare
Dark circle shade: an exploratory trial without a control group
Clinical trialInstrumental measurements of under-eye color went down, as did melanin, wrinkles and sagging. Without a control group, the effect of the oil itself is not established: the authors call for a randomized trial8.
Safety and expert viewsToxicology
Judged safe in 2007, confirmed in 2025
Expert assessmentCastor oil, ricinoleic acid and several ricinoleates are judged safe in the uses and concentrations described3. The highest use concentration reported in 2007 is 81%, in lipsticks2.
No ricin in the oil
ReviewRicin does not pass into the oil. The oil and ricinoleic acid may also increase the penetration of other substances through the skin2, a point to keep in mind for formulas that combine actives.
This page summarizes published literature on a cosmetic ingredient. It does not describe the effect of a finished product, which depends on its formula, and it is not medical advice. Several of the studies cited were run or funded by industry; this is indicated in the sources.
Which products use castor oil?
Our white label catalog includes 25 formulas with castor oil: the key active in 10 of them, a supporting ingredient in the others. Every category can be customized (formula, fragrance, packaging).
7Face
Material of lip balms and lip oils, also found in eye contour care.
3Body
Base of body balms and butters, men's care and pure oil for white label.
15Hair
Hair oil, serums and styling creams, notably for textured hair.
In our formulas, it is most often paired with
Vitamin E 17Argan oil 13Sweet almond oil 10Coconut oil 10Shea butter 9Castor oil, shea butter, coconut oil or jojoba oil?
Four vegetable fats often compared when choosing the base of a care product. Their chemistry differs, so their behavior in a formula does too.
| Castor oil | Shea butter | Coconut oil | Jojoba oil | |
|---|---|---|---|---|
| Chemical nature | Oil: about 90% ricinoleic acid1 | Butter: stearic (28 to 56%) and oleic (34 to 61%) acids11 | Oil: 92.1% saturated fatty acids, of which 47.7% lauric acid12 | Liquid wax: about 98% wax esters13 |
| EU regulation | No restriction | No restriction | No restriction | No restriction |
| Carmel catalog formulas | 25 formulas | 65 formulas | 65 formulas | 25 formulas |
Frequently asked questions about castor oil
What is castor oil?
What are the benefits of castor oil in cosmetics?
Does castor oil make hair grow?
What about castor oil for eyelashes and eyebrows?
We found no peer-reviewed study measuring an effect of castor oil alone on lashes or brows. Demand is high, but in formulation we talk about care and conditioning, not lengthening or regrowth.
Are there risks with castor oil?
How do you check the quality of a castor oil?
Through the fatty acid profile: in one study, three of nine cosmetic castor oils contained little ricinoleic acid, a sign of blending with other oils10. Ask for a certificate of analysis with the ricinoleic acid content.
Can you manufacture a castor oil product for my brand?
Yes. Our ISO 22716 certified lab offers 25 castor oil formulas (hair oils and serums, lip balms, body balms, beard care) that you can customize, or a custom formula. Samples are free.
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- Spotlight on prickly pear seed oilAnother vegetable oil to position in white label
Sources
Peer-reviewed studies and official regulatory sources, checked on November 2, 2026.
- Girdler K, Cabatu A, Olds H, Potts GA. Use of castor oil in dermatology: a narrative review Cureus. 2026;18(2):e103289. doi:10.7759/cureus.103289
- Cosmetic Ingredient Review Expert Panel. Final report on the safety assessment of Ricinus communis (castor) seed oil, hydrogenated castor oil, glyceryl ricinoleate, ricinoleic acid and related ricinoleates Int J Toxicol. 2007;26 Suppl 3:31-77. doi:10.1080/10915810701663150
- Fiume MM, Bergfeld WF, Belsito DV, et al. Re-review summary of Ricinus communis (castor) seed oil and ricinoleates as used in cosmetics Int J Toxicol. 2025;44(3_suppl):117S-122S. doi:10.1177/10915818251361102
- European Commission. CosIng, entry RICINUS COMMUNIS SEED OIL (CAS 8001-79-4, CE 232-293-8). ec.europa.eu/growth/tools-databases/cosing
- Phong C, Lee V, Yale K, et al. Coconut, castor, and argan oil for hair in skin of color patients: a systematic review J Drugs Dermatol. 2022;21(7):751-757. doi:10.36849/JDD.6972
- Dinkins J, Iwuala C, Akintilo L, et al. Commonly used hair oils in the Black community: a narrative review in their use to treat androgenetic alopecia Int J Dermatol. 2023;62(8):980-985. doi:10.1111/ijd.16657
- Fong P, Tong HH, Ng KH, et al. In silico prediction of prostaglandin D2 synthase inhibitors from herbal constituents for the treatment of hair loss J Ethnopharmacol. 2015;175:470-480. doi:10.1016/j.jep.2015.10.005
- Parvizi MM, Saki N, Samimi S, et al. Efficacy of castor oil cream in treating infraorbital hyperpigmentation: an exploratory single-arm clinical trial J Cosmet Dermatol. 2024;23(3):911-917. doi:10.1111/jocd.16056
- Maduri VR, Vedachalam A, Kiruthika S. "Castor oil" - the culprit of acute hair felting Int J Trichology. 2017;9(3):116-118. doi:10.4103/ijt.ijt_22_17
- Arroyo Negrete MA, Wrobel K, Acevedo Aguilar FJ, et al. Determination of fatty acid methyl esters in cosmetic castor oils by flow injection - electrospray ionization - high resolution mass spectrometry Int J Cosmet Sci. 2018 (publication en ligne). doi:10.1111/ics.12465
- Akihisa T, Kojima N, Katoh N, et al. Triterpene alcohol and fatty acid composition of shea nuts from seven African countries J Oleo Sci. 2010;59(7):351-360. doi:10.5650/jos.59.351
- Orsavova J, Misurcova L, Ambrozova JV, et al. Fatty acids composition of vegetable oils and its contribution to dietary energy intake and dependence of cardiovascular mortality on dietary intake of fatty acids Int J Mol Sci. 2015;16(6):12871-12890. doi:10.3390/ijms160612871
- Gad HA, Roberts A, Hamzi SH, et al. Jojoba oil: an updated comprehensive review on chemistry, pharmaceutical uses, and toxicity Polymers (Basel). 2021;13(11):1711. doi:10.3390/polym13111711
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