Sunscreen that has gone past its expiry date will not protect you from sun damage.
How does sunscreen protect you from the sun?
The BAD explained that sunscreens either act like “sponges, mopping up the UV radiation”, or act as “mirrors, bouncing UV straight back off the skin”.
“Be aware that if you choose a low SPF it may still have a high level of stars.
“Not because it is providing lots of UVA protection, but because the ratio between the UVA and UVB protection is about the same,” the BAD pointed out.