Summer Sport Sunscreen: A Guide for Athletes
Protection that performs through games and training.
SPF 15 blocks ~93% of UVB, SPF 30 ~97%, SPF 50 ~98%, SPF 100 ~99%.
Apply too little and an SPF 50 can perform more like an SPF 15 in real life.
Questions we get a lot
Does a higher SPF mean more protection?
Only marginally. SPF 30 blocks about 97% of UVB, SPF 50 about 98%, and SPF 100 about 99% — and no sunscreen blocks 100%. Applying enough and reapplying matters far more than chasing a high number, and SPF says nothing about UVA protection.
What is the two-finger rule for sunscreen?
The two-finger rule is a simple guide: squeeze sunscreen in two lines along your index and middle fingers, base to tip, to cover the face and neck. It approximates the research-backed amount (about a quarter to half teaspoon) that most people otherwise under-apply.
Does sunscreen fully prevent tanning?
No. A tan is the skin's response to DNA damage, and because no sunscreen blocks 100% of UV — and most people under-apply — some tanning can still occur. Sunscreen reduces the damage, but there is no safe tan from the sun.
r/SkincareScience: 'Is SPF 100 a marketing gimmick or worth it?'