Sunscreen with high SPF is considered to be more effective but the truth is high SPF doesn't offer you more protection. SPF 30 blocks 97% of UVB radiation as SPF 50 blocks 98%. SPF 70 will block more UVB radiation but this doesn't mean it offers more protection. However, choosing a sunscreen with lower SPF concentration like SPF 30 and 50 instead of SPF 70 is better for your skin.