To make sure they were up to the mark, I tested them multiple ways, including: on top of my usual skincare, without any skincare at all (à la post-swim skin), underneath makeup, on top of makeup, and as a top up half way through the day.
Article source: https://www.huffingtonpost.co.uk/entry/face-sunscreen-spf-reviewed_uk_6a352bace4b0dfdabcee3458