Overview
- Consumer group Which? posted a social media clip telling people to look for the small open‑jar icon that shows how long a product stays effective after first opening.
- The Period After Opening label appears as a jar with a number and an M, such as 12M, which means the sunscreen should be replaced once that many months have passed since opening.
- Experts advise writing the date you first opened the bottle with a marker so you can tell if last year’s sunscreen is still within the safe‑use window.
- Dermatologist Rutledge Forney reports treating sunburns from expired products because UV filters break down over time, which lowers protection.
- The NHS says to choose SPF 30 or higher with at least four‑star UVA protection and to use enough sunscreen, about 6 to 8 tablespoons for full‑body coverage.