Octocrylene
Octocrylene is an oil soluble liquid UV filter often used as an additive in sunscreen. Due to its emollient properties it also finds use in hair spray, tannin oil, conditioners, and creams.
The USA FDA as well as the EU allows use up to 10% in the formula with Health Canada allowing a maximum use level of 12%
Being hydrophobic it does not mix or dissolve in water and therefore adds water-resistant properties to sunscreens. Additionally, because it is quite photostable it doesn’t deteriorate in the presence of UV light.
