Did you know that sunscreen that doesn’t say “broad spectrum” on the label is only protecting you from half of the sun’s effects? Two forms of the sun’s radiant energy that affect your skin are UVA and UVB. All sunscreens protect against UVB rays, but not all protect against UVA rays.
UVA and UVB
UVA are the longest of the sun’s ultraviolet (UV) rays—they penetrate more deeply into your skin and are responsible for skin damage and premature aging. The shorter wavelength UVB rays cause a mixed bag of effects. On one hand, UVB helps your body to transform sunlight into vitamin D which is an important nutrient to many of your body’s functions. On the other hand, you may have experienced one of UVB’s other effects—sunburn.
Why broad spectrum?
Too much of either type of ultraviolet light can cause skin cancer, making broad-spectrum sunscreen a healthy choice. Also labeled as multi spectrum or UVA/UVB protection, this designation has nothing to do with SPF which stands for “sun protection factor.” The SPF number only relates to how long it will take the UVB (those rays that lead to sunburn) to redden skin—it doesn’t take the equally damaging UVA rays into account—that’s why you should look for a sunblock that’s broad-spectrum, multi-spectrum or says it protects from both UVA and UVB.
Did you know? The sun emits a third ultraviolet wavelength, UVC. The shortest of the three UV rays, it is mostly absorbed by the Earth’s atmosphere.