Ricinus Communis (Castor) Seed Oil
Castor oil
No meaningful concern for most people; irritation is possible but rare.
Also written as: Ricinus Communis Seed Oil · Castor Oil
What it is
Castor oil is cold-pressed from the seeds of Ricinus communis and is about 90% ricinoleic acid, a fatty acid carrying a hydroxyl group. That single chemical difference makes it far more viscous and far more polar than other plant oils, which is why it gives a glassy shine, wets pigments beautifully and is a mainstay of lip products and cleansing balms. Its highest reported use concentration in cosmetics, 81%, is in lipstick.
What it does well
Gives high shine and a durable film
Its polarity and viscosity make it uniquely good at dispersing pigments and at forming a glossy, cushioning layer, which is why it is difficult to replace in lip formulations.
Moderate evidence
Worth knowing
Widely and wrongly feared because castor seeds contain ricin
The seed does contain ricin, a highly toxic protein, but the Cosmetic Ingredient Review safety assessment is explicit that castor oil does not contain it, because ricin does not partition into the oil during pressing. This is one of the clearer cases of a scary-sounding fact that does not apply to the cosmetic ingredient.
Matters most toAnyone who has read that castor oil is related to a poison.
Very sticky, and an occasional contact allergen in lip products
The tackiness that makes it good in lipstick makes it uncomfortable in facial products at high levels. Castor oil and its derivatives are also recognised, though uncommon, causes of allergic cheilitis in people who react to lip cosmetics.
Matters most toPeople with persistent lip dermatitis of unknown cause.
Where the EU stands
No specific restriction
Not listed in any Annex of the EU Cosmetics Regulation, so there is no specific concentration limit; it is still covered by the general safety assessment every cosmetic product must pass before sale.
Sources (1)
Every link goes to the original: a journal, a PubMed record or an EU document.
- [1]Final report on the safety assessment of Ricinus Communis (Castor) Seed Oil, Hydrogenated Castor Oil, Glyceryl Ricinoleate, Glyceryl Ricinoleate SE, Ricinoleic Acid, Potassium Ricinoleate, Sodium Ricinoleate, Zinc Ricinoleate, Cetyl Ricinoleate, Ethyl Ricinoleate, Glycol Ricinoleate, Isopropyl Ricinoleate, Methyl Ricinoleate, and Octyldodecyl Ricinoleate
International Journal of Toxicology (Cosmetic Ingredient Review) · 2007 · doi:10.1080/10915810701663150
States plainly that castor oil does not contain ricin, because ricin does not partition into the oil, and assesses castor oil and its derivatives as safe as used in cosmetics.
