SPF 100 is barely better than SPF 50.

No, it’s not significantly better.

SPF 50 blocks about 98% of UVB rays. SPF 100 blocks about 99%. That extra 1% sounds nice, but in real-world use it doesn’t translate to meaningfully better protection.

The real problem is that people treat SPF 100 like a force field. They think they can skip reapplying or stay out longer. That’s dangerous. No sunscreen lasts all day, no matter the number. You’re better off with SPF 50 that you actually reapply every two hours than SPF 100 you put on once and forget.

Also, SPF 100 sunscreens often have more chemical filters or higher concentrations, which can be more irritating for sensitive skin. And they cost more.

The best sunscreen is the one you reapply properly.