Octisalate, an organic UV filter, readily absorbs through the skin at levels 10 times more than 0.5 nanograms per milliter, the FDA’s cutoff for systemic exposure. This cutoff is the maximum concentration that may be found in blood before there are potential safety concerns. The FDA has requested additional safety testing when a sunscreen is absorbed above this level (Walters 1997, Matta 2020).
The FDA 2019 proposed update suggests there is insufficient data to determine whether octisalate can be classified as safe and effective to use in sunscreens (FDA 2019). A case report showed that the chemical has been linked to allergic contact dermatitis (Singh 2007). Analysis of high throughput screening assays by the Environmental Protection Agency suggests octisalate may have endocrine effects, weakly binding to the estrogen receptor.