Isononyl Isononanoate

Isononyl isononanoate is a synthetic emollient ester used to improve slip and reduce tack, commonly present around 1–20% in moisturizers, sunscreens, and makeup. Clinical and patch-test experience generally shows a low irritation profile for this type of fatty ester, with reactions being uncommon and usually limited to highly reactive or compromised skin. Because it is not an active, not pH-dependent, and not a fragrance component, its overall irritancy potential is very gentle but not completely inert. Safety Notes: Isononyl isononanoate is a lightweight emollient/skin-feel modifier that appears at low levels (~0.1–1%) in lotions, sunscreens, and serums to improve slip and reduce tack, and at mid levels (2–15%) as part of the primary emollient phase in many leave-on creams and makeup. In consumer-available anhydrous oils, balms, primers, and high-slip body products, it can be used as a major base emollient/solvent and commonly reaches 20–40% in finished formulas; rinse-off products typically sit lower due to dilution and wash-off economics.