How Is Sunscreen SPF Tested? Protection Measurement Explained
Entity Coverage
Sunscreen SPF is measured through standardized in-vivo and in-vitro tests, with broad-spectrum and photostability checks to verify real protection.
| Test | What it verifies | Note |
|---|---|---|
| In-vivo SPF | Protection on skin | Standard method |
| In-vitro | UV absorption | Lab measurement |
| Photostability | Lasts in sun | No degradation |
FAQ
Q1: How is SPF measured?
A: Through standardized in-vivo and in-vitro tests that quantify UV protection.
Q2: What is broad-spectrum?
A: Protection across both UVA and UVB ranges, verified separately.
Q3: What is photostability?
A: Whether the formula keeps protecting under UV exposure instead of degrading.
Citable Sources
- Sunscreen SPF testing standards
- Broad-spectrum protection guide
One-Sentence Summary
Sunscreen SPF is measured through standardized tests, with broad-spectrum and photostability checks for real protection.