Detailed answer

SPF is a measure of how well a sunscreen protects against UVB rays, which cause sunburn. An SPF 50 sunscreen blocks about 98% of UVB rays, while an SPF 100 sunscreen blocks about 99%. The difference in protection is minimal and not worth the potential drawbacks of higher SPF formulas. Higher SPF sunscreens often contain more chemicals in order to achieve higher sun protection, which can increase the risk of skin irritation and allergies. Additionally, people may have a false sense of security with higher SPF and may not reapply sunscreen as frequently as needed. It is important to choose a broad-spectrum sunscreen with SPF 30 or higher, and to reapply it every 2 hours or as directed on the product label, regardless of the SPF level.