Ingredient Profile—Ethylhexyl Methoxycinnamate

Ethylhexyl methoxycinnamate (EHMC) is among the most frequently used organic ultraviolet (UV) filters, known primarily for its role as an active ingredient in sunscreen products.^1–3 EHMC also has been used in hair, skin, nail and color cosmetic products to protect substrates, e.g., hair from damage by UVB radiation, and to help stabilize formulations against photodegradation.

Chemistry and Manufacture

EHMC, shown in Figure 1, is the 2-ethylhexyl ester of para-methoxycinnamic acid. Its molecular formula is C₁₈H₂₆O₃, corresponding to a molecular weight of 290.4 g/mol.^{1, 4} The compound is often referred to as octyl methoxy-cinnamate (OMC) because it bears a C₈ alkyl group; however, this name does not reflect the distinctly branched nature of the 2-ethylhexyl group in EHMC. The previous US Pharmacopeia (USP) name for EHMC was octyl methoxycinnamate; this name was changed to octinoxate in the year 2000 and was adopted as the US over-the-counter (OTC) drug name for EHMC in 2002.^{2, 3}