health

SPF measures protection against burning only, and the numbers are not proportional. SPF 30 blocks about 97 percent of UVB and SPF 50 about 98. The gap that matters is UVA, which SPF does not measure at all.

3 min read  ·  5 Sep 2026

A vaccine shows your immune system a harmless preview of a pathogen so it can build a memory of it in advance. The training is real; only the threat is fake.

4 min read  ·  5 Sep 2026