Ethylhexyl methoxycinnamate, also known as octinoxate, is an ester formed from methoxycinnamic acid and 2-ethylhexanol. It is the oldest and most commonly used UVB-absorbing active ingredient in sunscreen. UVB rays are the type that cause sunburn, whereas UVA rays are the type that prematurely age your skin. Both types of rays can cause skin cancer. While ethylhexyl methoxycinnamate does provide some UVA protection, it does not protect against the entire range of UVA wavelengths. This means that ethylhexyl methoxycinnamate should be combined with additional active ingredients that protect against the full spectrum of UVA wavelengths.

UV absorbers like ethylhexyl methoxycinnamate are also known as chemical sunscreen ingredients, which work by absorbing UV light and then transforming that light energy into some other form of energy, such as heat. This is in contrast to physical sunscreens, which protect skin by using physical UV filters to block or deflect UV light. Ethylhexyl methoxycinnamate has been proven safe as used in sunscreen products through decades of research and thousands of studies.