Homosalate is an organic compound used in some sunscreens. It is an ester formed from salicylic acid and 3,3,5-trimethylcyclohexanol, a derivative of cyclohexanol. C16H22O3 https://pubchem.ncbi.nlm.nih.gov/compound/Homosalate#section=Top.
2021-03-29
An oil-soluble chemical sunscreen agent that protects the skin from UVB (295-315 nm) with a peak protection at 306 nm. Homosalate is not a strong UV filter in and of itself (gives only SPF 4.3 protection at max. allowed 10% concentration) and it is not photostable (looses 10% of its SPF protection in 45 mins) so it always has to be combined with other sunscreens for proper protection. Its big advantage, though, is that it is a liquid and is excellent for dissolving other hard to solubilize powder sunscreen agents, like the famous Avobenzone.
Regarding Homosalate's safety profile, we do not have the best news. In-vitro (made in the labs) studies have shown that it might have some estrogenic activity. Do not panic, these studies were not conducted on real humans under real world conditions. Still, if you are a 'better safe than sorry' type, be careful when using Homosalate containing sunscreens long-term and full-body
https://incidecoder.com/ingredients/homosalate