Application & Usage Myths
The Right Way to Apply Sunscreen Before Swimming
Timing and technique for water resistance to work.
SPF 30 lets through about 50% more UVB than SPF 50 (3% vs 2%).
No sunscreen blocks 100% of UV, which is why reapplication matters more than chasing a higher SPF.
Questions we get a lot
How much sunscreen should I actually apply?
Most people apply far too little. Sunscreen is tested at 2 mg/cm², but typical use is a quarter to half that — which can drop an SPF 50 to real-world SPF 15 or lower. Aim for about a quarter to half teaspoon for the face and roughly a shot glass (1 oz) for the whole body.
How often do I need to reapply sunscreen?
Reapply about every two hours of sun exposure, and immediately after swimming, heavy sweating or toweling off. Indoors and away from windows you generally don't need to reapply, but a single morning application also wears off — so reapply if you're near windows or heading back outside.
r/AsianBeauty: 'Am I using way too little sunscreen on my face?'