The sun emits ultraviolet light, which hits the earth and plays a role in skin damage. You’ll often hear about UVA and UVB rays in relation to sunburn, wrinkles and sunscreens.


UVA rays are the most common form of UV radiation that reaches us here on Earth. We are exposed to UVA rays during all day light hours and they can penetrate glass and clouds. UVA rays penetrate the skin to a deeper level than UVB rays. UVA rays have long been associated with photoaging – that’s aging and wrinkling! More recently it has been found that UVA rays contribute to skin cancers.


UVB rays are the rays that are usually responsible for that dreaded sunburn! As UVB rays don’t penetrate the skin as deeply as UVA rays do, they damage the skin’s outermost layers (the epidermis) and are responsible for that dreaded C word… Cancer – in this case skin cancers. Unlike UVA rays the amount of UVB rays reaching your skin does vary by time of day/year and location. This is why you are advised to protect your skin more thoroughly from 10-4pm in the USA and more so in the warmer months (though it’s recommended everyone wears a daily sunscreen all year round).


So What Does Broad Spectrum Mean?


If you’ve ever studied sunscreen packaging you will have noticed that some are labelled as Broad Spectrum. Put simply a Broad Spectrum sunscreen has been shown to protect you from both UVA and UVB rays if applied correctly. As you know now it’s important to be protected from both in order to help prevent sunburn (and skin cancers) and skin aging.


In 2012 the FDA (US Food and Drug Administration) introduced new requirements for sunscreens purchased over the counter in the US. To be labelled Broad Spectrum they now need to provide UVA proportional to UVB protection.


Learn more about How Do Sunscreens Work? Sunscreen Active Ingredients