This is interesting – although it has come at the wrong end of the year – and is something I and others have been concerned about for years.
The idea that slapping suncream on to protect your skin from UV damage has been so widely promoted that it is assumed to be a risk-free no-brainer. I’ve always been concerned about the unpublicised risk of the suncream chemicals. After all, some of them will be absorbed into the skin and bloodstream, surely? This article suggests the risk is real, and increases with time as the sun degrades the ingredients, turning them into toxic byproducts.
After two hours, sunscreen that includes zinc oxide loses effectiveness, becomes toxic: study
— Read on phys.org/news/2021-10-hours-sunscreen-zinc-oxide-effectiveness.html