Sunscreens usually have labels indicating whether they block UVA or UVB rays, or both. What’s the difference for skin aging, skin cancer, and wrinkles -- and why is it significant?
Two types of harmful light rays come from the sun: ultraviolet A radiation (UVA), and ultraviolet B radiation (UVB). According to the American Academy of Dermatologists, both types can cause skin cancer, but each can affect the skin in additional ways:
- UVA radiation can cause photoaging, or premature aging of the skin, resulting in wrinkles, uneven pigmentation, and texture changes.
- UVB radiation is the main cause of sunburn.
So-called “broad-spectrum” sunscreens protect against both UVA and UVB rays. As of June, 2012, the US Food and Drug Administration’s requirements for product labeling have changed so that a sunscreen can only claim to protect against skin aging if it blocks both UVA and UVB rays, and offers an SPF of 15 or higher.
Sunscreens. American Academy of Dermatologists Public Information Sheet. Accessed August 28, 2012.