Aluminum Starch Octenylsuccinate

Aluminum Starch Octenylsuccinate is a modified starch absorbent/mattifier used in leave-on cosmetics (often ~1–10%) to reduce oiliness and improve texture, and it is generally considered low-irritant in patch testing because it is largely inert and not pH-active. The main risk is mechanical dryness or frictional irritation in very compromised or eczematous skin (especially with frequent use in powders), but true chemical irritation or sensitization is uncommon. Given sensitive-skin safety priorities, it fits best as very gentle rather than completely inert. Safety Notes: In commercial leave-on skincare and color cosmetics, Aluminum Starch Octenylsuccinate commonly appears at low levels (~0.1–1%) as a slip/texture aid and oil-absorption booster in lotions, sunscreens, and primers, with some rinse-off cleansers also using similar low single-digit levels for sensorial benefits. High-strength OTC consumer products marketed for strong mattifying, blurring, or dry-touch finishing (e.g., face powders, oil-control primers, and some mineral/soft-matte sunscreens) can push starch-based absorbents into the mid-to-high teens and up to ~25% in powder-heavy systems. No specific FDA/EU maximum limit applies for this ingredient in cosmetics; practical upper bounds are driven by aesthetics (drag/chalkiness) and stability rather than regulation.

Suitability