This is a lingering myth left over from the ’80s, when sunscreen technology was not as advanced as it is today. SPF 30 blocks 97 percent of UVB rays. SPF 50 blocks 98.3 percent. SPF 100 blocks 99 percent. Sounds like almost the same numbers, but what it really means is that SPF 30 allows 3 percent of UVB rays to pass, while 50 allows only 1.7 percent -- almost twice the protection.
So how do you pick your sunscreen? The American Academy of Dermatology recommends daily use of at least SPF 30 broad-spectrum sunscreen, with higher SPF choices for extended sun exposure or for anyone with a history of skin cancer or other medical concerns that warrant extra protection.
Also, be sure to choose only broad-spectrum protection, which means high-quality UVA and UVB protection. UVA rays are longer wavelength rays and reach deeper into the skin, contributing to wrinkling and loss of skin quality. But the old easy division into “B causes burning and A causes wrinkling” has been proven false. Both types of rays cause all three types of damage (burning, aging and cancer), just in varying degrees.