The American Academy of Dermatology recommends an broad spectrum sunscreen with sun protection factor 30. SPF 30 will block about 97% of the sun's UVB rays that cause sunburn and skin cancer.
Higher SPF levels, such as SPF 50 or 100, block slightly more UVB rays (about 98-99%), but the difference is not significant compared to SPF 30. No sunscreen can block 100% of UV rays.
More important than a super high SPF is applying sunscreen correctly. Apply a liberal amount to all exposed skin, reapply every 2 hours, and don’t rely solely on sunscreen over protective clothing and shade.
Check expiration dates on sunscreen, as potency can break down over time. Choose lotion or cream formulas without oxybenzone to avoid skin irritation and potential hormone disruption concerns. Reapply liberally for optimal protection.