SPF Numbers Explained

SPF measures protection against UVB rays only. SPF 30 blocks about ninety-seven percent of UVB rays; SPF 50 blocks about ninety-eight percent.

Broad-spectrum protection is more important than high SPF numbers. Broad-spectrum means the product also blocks UVA rays, which cause aging and pigmentation. A broad-spectrum SPF 30 protects better than a regular SPF 50 that only covers UVB.