What it is
Hydroxystearic acid is a long-chain fatty acid bearing a hydroxyl group, most commonly the 12-hydroxy form derived from stearic acid. In formulations it helps emulsify and stabilize oil-and-water systems, adjust viscosity, and improve the spread and feel of creams and sticks. In sunscreens it can aid in keeping pigments and other ingredients evenly dispersed.
Safety & warnings
Hydroxystearic acid is generally considered well tolerated for topical use and is not a recognized fragrance allergen. As a processed fatty-acid derivative used at functional levels, it is not typically flagged as highly comedogenic, though those very prone to clogged pores may prefer to monitor heavy leave-on use.
Origin & sourcing
Typically produced from stearic acid, a fatty acid that can be sourced from vegetable oils or animal fats and then chemically processed.
Questions everyone asks
What is hydroxystearic acid used for?
It works as an emulsifier and stabilizer that helps blend oil and water phases, control thickness, and improve a product's texture and spread.
Where does hydroxystearic acid come from?
It is made from stearic acid, which can be derived from vegetable or animal fats and then chemically modified.