Sunscreen has the strongest evidence base of anything in your bathroom, and yet it remains buried under more myths than any other product. Dermatologists spend half their appointments un-teaching them. Let us save everyone some time.
Myth one: you do not need it on cloudy days
Up to eighty per cent of UV radiation passes through cloud cover. UVA, the ageing wavelength, is remarkably consistent year-round and passes through glass too, which is why the classic dermatology photos of long-haul lorry drivers show dramatic ageing on the window side of the face. If it is daytime, UVA is present. That is the whole rule.
Myth two: darker skin does not need SPF
Melanin does provide some natural protection, but nowhere near enough to skip sunscreen. Deeper skin tones can and do experience UV damage, and hyperpigmentation, which disproportionately affects darker skin, is made significantly worse by unprotected sun exposure. Modern formulas have largely solved the white-cast problem that made this advice hard to follow.
Myth three: the SPF in your makeup counts
Only if you apply a quarter teaspoon of foundation to your face, which nobody does. SPF testing assumes a thick, even layer. The dusting of powder or dab of tinted moisturiser most of us wear delivers a fraction of the number on the label. It is a bonus, not a plan.
Myth four: one application lasts all day
Sunscreen degrades with light exposure and wears off with sweat and touch. On a normal indoor day, a morning application is reasonable. On a beach day, reapplication every two hours is the difference between protection and a false sense of it.
Find a formula you do not hate, because the best sunscreen remains, as ever, the one you will actually wear.
