Factual info about the shelf life of sunscreen?

[CalmerViolet]

I seem to have 13 bottles in the house, of varying ages.

None have 'use by' dates.

Is sunscreen from 3 or 4 years ago still OK to use?

Does anyone know for sure? I obviously don't want to take risks, but I don't want to be needlessly wasteful, either.

I think I remember something about the spf halving after a year and again after another year. So 4 years old will be pretty useless really.

day few different sources state that unless otherwise marked they shoyld ladt up to 3 years. So I'd keep the ones from 2-3 years ago if youre certain of their age but bin the rest.

They normally have a wee box on them with a number in and that tells you how many months they are ok for

I would use last years but not older that that