INCI Name: Stearic Acid
What is it: Stearic Acid A fatty acid that occurs naturally in animal and plant fats (typically coconut or palm oil), stearic acid is white, solid, often crystalline, and with a mild odour. It’s a major component of cocoa and shea butter. Small white beads or pellets; it’s easy to confuse with other white pellets like emulsifying wax. Stearic Acid is a fatty acid typically produced by hydrolysis of common animal and vegetable fats and oils, followed by fractionation (distillation or crystallisation) of the resulting fatty acids. Pressing methods separate the liquid unsaturated fatty acids from the solid saturated fatty acids.
Stearic Acid that is used in cosmetics is usually pressed two or three times, resulting in different concentrations. Cosmetic-grade stearic acids are usually mixtures of fatty acids, depending on how they’re manufactured and where they come from (often they’re combined with palmitic acid). There are several grades of stearic acid available commercially.
Usage Rate: For emulsions, generally 1–5%. For anhydrous products, 1–40/50%.
Benefits: Main benefits: Softens and smooths the skin's surface while also helping to maintain the skin barrier. It also works as a surfactant, though it is often used as an emulsifier to thicken products and improve their texture, says Petrillo.
Uses: Stearic Acid is an emulsifier, emollient, and lubricant that can soften skin and help to keep products from separating. Stearic acid is used in hundreds of personal care products, including moisturiser, sunscreen, makeup, soap, and baby lotion. It is also used in adhesives, lubricants, laundry products and paper products. Research shows that the ingredient may help burns heal.
Storage: Stored somewhere cool, dark, and dry, stearic acid should last at least two years.
Caution: Keep away from heat.