Sunscreen
Sunscreen — how to choose
Sunscreen is the only product in a routine with strong evidence behind it for preventing visible ageing. Everything else improves how skin looks; sunscreen prevents the damage in the first place.
Korean sunscreens are worth buying specifically because they solved the texture problem. Western formulas at SPF50 are frequently thick, white and unpleasant, which is why people skip them. Korean ones behave like moisturisers, and a sunscreen you actually wear beats a better one you do not.
Reading the label
SPF measures protection against UVB — the rays that burn. SPF50 blocks roughly 98%, SPF30 about 97%. The gap is smaller than the numbers suggest.
PA rating measures UVA — the rays that age skin and pass through glass. PA++++ is the highest. This matters as much as SPF and gets less attention than it should.
Chemical or mineral
Chemical filters absorb UV and convert it to heat. They are cosmetically better — no white cast, lighter texture — and most Korean sunscreens use them.
Mineral filters (zinc, titanium dioxide) sit on the surface and reflect. Better for genuinely reactive skin, but more likely to leave a cast.
Neither is safer than the other in any meaningful sense. Choose on how it feels, because that determines whether you wear it.
How much, and how often
Two finger-lengths for the face and neck. Almost everyone applies less than a third of that, which means the SPF on the bottle is not what you are getting.
Reapply every two hours in strong sun. Indoors with no direct window light, once in the morning is fine.
Sticks and cushions are for reapplying over makeup, not for your main application — the format makes it very hard to apply enough.
Frequently asked
Do I need sunscreen in winter, or indoors?
UVA passes through cloud and glass. If you sit near a window, yes. On a dark winter day away from windows, it matters less.
Does makeup with SPF count?
No. You would need far more foundation than anyone wears to reach the stated protection.
What is a tone-up sunscreen?
One that leaves a deliberate brightening cast. Some people want it, some do not — it is a preference, not a feature.
Will sunscreen break me out?
More often it is inadequate removal rather than the sunscreen. Try a proper double cleanse before blaming the product.
How much sunscreen should I apply, and how often should I reapply?
About two finger-lengths, roughly ¼ teaspoon, for the face and neck; using less gives much lower protection than the label promises. Reapply every two hours in direct sun and after sweating or swimming. A sun stick, such as Round Lab Birch Juice or SKIN1004 Hyalu-Cica Silky-Fit, makes topping up over makeup easier.
Do Korean sunscreens leave a white cast?
Many modern Korean sunscreens are made to blend in without a white cast, for example Beauty of Joseon Relief Sun Aqua-Fresh and Anua Zero-Cast. Tone-up formulas such as VT PDRN Essence Moist Tone Up Sun Essence deliberately leave a light brightening tint, so if you don't want that, choose one without tone-up in the name.
