Tridecyl Trimellitate

Tridecyl Trimellitate is a high–molecular weight emollient/film-forming ester commonly used in leave-on products (often a few percent up to higher levels in color cosmetics) to improve slip and reduce transepidermal water loss. As a non-volatile, non-reactive lipid-like material, it has low inherent irritancy in patch testing and lacks the pH-dependent or biologically active mechanisms that drive stinging/burning. In very reactive or eczema-prone patients, occlusion or individual intolerance is still possible, but clinically it aligns best with a very gentle, low-risk profile. Safety Notes: Tridecyl Trimellitate is used as an emollient/film former and pigment wetting/binder in leave-on color cosmetics and some skincare; in broader skincare it often appears at low supportive levels (~0.1–2%) to improve slip and reduce tack in creams/lotions and sunscreen vehicles. In long-wear lip products, foundations, and other high-payoff anhydrous or low-water systems marketed OTC, it can be a major part of the oil phase and is observed in the ~10–40% range, with the upper end driven by high-gloss/long-wear, transfer-resistant formats. It is uncommon in rinse-off products (typically low, if present) since its performance benefits are primarily for leave-on film formation and wear.