A synthetic powdery thickening agent, absorbent, and anti-caking agent used in cosmetics. When listed among the first few ingredients in a product, chances are the product will have a powder-like matte finish and fast dry time.
The independent Cosmetic Ingredient Review Panel has determined that aluminum starch octenylsuccinate, as currently used in cosmetics, is safe.
Reference for this information:
International Journal of Toxicology, 2002, Supplement 1, pages 1-7