oil
Castor Oil
The thick, sticky, faintly sweet workhorse — used by Refy and Ceremonia in brow gels and hair oils, and used industrially across virtually all clean lipsticks and balms as a glide and structure agent. Ricinoleic acid (~90% of fatty acid content) is unique in nature and gives castor its distinctive viscosity and mild antimicrobial properties.
Benefits
- unique ricinoleic acid content (~90%)
- structural backbone of clean color cosmetics
- occlusive lash/brow conditioner with anecdotal growth claims
Example uses
- lip balms and tinted balms
- brow and lash conditioners
- hair oils
- color cosmetics base
Mechanism of action
Roughly 90% of fatty-acid content is ricinoleic acid — a hydroxylated 18-carbon monounsaturated fatty acid unique in commercial plant oils. The hydroxyl group raises viscosity (castor is ~7× more viscous than other vegetable oils), polarity, and humectancy, while giving ricinoleate salts mild surfactant character. On skin and hair it acts primarily as an occlusive emollient and gloss-building film-former; the prostaglandin EP3 receptor agonism documented in pharmacology is the basis for both its laxative effect orally and the speculative scalp/lash hair-growth claims topically.
Clinical evidence · Anecdotal
Excellent evidence as a structural cosmetic excipient; clinical data for hair/lash/brow growth claims is essentially absent — extrapolation from EP3 pharmacology, not skin trials.
Effective concentration range
1–100% in oils; 5–50% in lipsticks and balms as structurant
Formulation notes
Cold-pressed Indian or Brazilian-sourced is typical. Hydrogenated castor oil (PEG variants) is widely used as an emulsifier — look for non-PEG forms in clean positioning. Pairs with rosehip, jojoba, and shea in balm and lip systems.
Watchouts
Hair-growth claims (lashes, brows, scalp) outpace the clinical evidence. Castor wax allergy is rare but documented.
Controversies & overclaims
The hair-, lash-, and brow-growth claims are the headline overclaim — no controlled study supports them, and the prostaglandin-analogue framing borrows credibility from bimatoprost (a separately patented latanoprost-class prescription). 'Cold-pressed organic castor' marketing is largely meaningless: the cosmetic-grade product is highly refined regardless.
Market positioning
Sold as the natural growth-and-gloss workhorse — and is undeniably the gloss workhorse, with structurant duty across virtually every clean lipstick on the shelf. The growth story is folkloric, not clinical.
Comedogenicity
1 / 5
Sensitisation risk
Low
INCI & aliases
Ricinus Communis Seed Oil
ricinus communis · ricinus oil · ricinoleic acid
Clean beauty perception
Trusted — heritage ingredient with clean-formulation utility.
Brands using Castor Oil
Related ingredients
Graph relationships
Timeline