What it is
Homosalate is an organic compound (C16H22O3) and a member of the salicylate family of sunscreen agents. Its salicylic acid portion absorbs ultraviolet light in the UVB range, roughly 295 to 315 nm, converting that energy to heat, while its trimethylcyclohexyl portion makes the molecule oil-soluble. Because its UV absorption is fairly narrow, homosalate is typically combined with other filters to broaden a formula's overall protection.
Spectrum coverage
UVB
Regional approval · max %
Safety & warnings
Homosalate is widely used as a UVB absorber and, in topical studies, has not been reported to cause genotoxic, phototoxic, or photosensitizing effects. Laboratory studies have noted antiandrogen activity in cell systems, though the published literature states that no adverse events of this kind have been reported in humans. Skin penetration is limited, with roughly a quarter reaching the outermost skin layer in study conditions. Regulators in some markets have set concentration limits, which are shown separately on this page.
Origin & sourcing
Homosalate is a synthetic ester. It is manufactured by Fischer-Speier esterification, combining salicylic acid with 3,3,5-trimethylcyclohexanol, a compound derived from the hydrogenation of isophorone.
History
Homosalate is one of the older organic UV filters and is among the most common UVB absorbers in sunscreen, appearing in a large share of formulations sold in the United States.
Questions everyone asks
What kind of UV protection does homosalate give?
It is a UVB filter, absorbing ultraviolet light in roughly the 295 to 315 nm range; it does not cover the UVA range on its own.
Why is homosalate combined with other filters?
Its absorption is fairly narrow, so it is usually paired with additional filters to broaden a sunscreen's overall protection.
Is homosalate natural or synthetic?
It is synthetic, made by esterifying salicylic acid with 3,3,5-trimethylcyclohexanol.