What it is
Castor oil is a thick, glossy fixed oil pressed from the seeds of Ricinus communis and is unusually rich in the hydroxy fatty acid ricinoleic acid, which gives it high polarity and viscosity. These properties make it an excellent wetting and dispersing medium for pigments and a structuring emollient in anhydrous balms, lip products, and sticks. It imparts shine, cushion, and good pigment payoff.
Safety & warnings
Cosmetic castor oil is generally well tolerated and has a long history of use in lip and stick products. The toxic seed protein ricin is not present in the refined oil. Castor oil is fairly polar and is generally considered low on the comedogenicity scale, though occasional contact sensitivity has been reported. It is not a recognized fragrance allergen.
Origin & sourcing
Natural, plant-derived: a fixed oil expressed from the seeds of the castor plant (Ricinus communis). The cosmetic oil is purified and contains none of the toxic protein found in the raw seed.
Questions everyone asks
Is castor oil safe even though castor seeds are toxic?
Yes. The toxin ricin is a protein that stays in the seed cake and is not present in the refined oil used in cosmetics, so cosmetic castor oil is considered safe for topical use.
Why is castor oil common in sticks and lip sunscreens?
Its high viscosity and polarity make it excellent at wetting pigments and adding shine and cushion, which suits anhydrous sticks and tinted lip formats.