UVA rays damage skin and can contribute to skin cancer. You should choose a sunscreen that offers broad-spectrum protection (from UVA & UVB).
The mineral zinc oxide provides full UVB & UVA protection. Zinc oxide is the only active ingredient in all Badger sunscreens.
Broad spectrum claims are verified by testing. All Badger sunscreens have been tested and provide full broad spectrum sunscreen protection.
Just because a sunscreen has a high SPF does not necessarily mean that you are being protected from damaging UVA rays. SPF is only a measure of how well a sunscreen protects you from sunburn, which you get only from UVB rays. UVA (ultraviolet-A) is a longer wavelength of sunlight that makes up 95% of all UV light reaching the earth's surface. It passes right through clouds and glass, and it is pretty much the same strength throughout the day and the year.
Currently the US and Canada do not require sunscreens to offer any UVA protection. Many sunscreens on the shelves, even those intended for babies and kids, offer little or no protection from UVA rays. As of January 2013 the FDA requires substantiation of broad spectrum or UVA claims made by sunscreens. This means that any "Broad Spectrum Sunscreen" or "UVA Protection" claims must be proven by passing results on a critical wavelength test (see below).
Badger sunscreens use the mineral zinc oxide, which provides broad spectrum protection from UVA and UVB rays. We had our sunscreens independently tested and they earned "Superior UVA Protection" based on US and international rating systems.
UVA penetrates deeper into the skin than UVB, and will cause immediate suntan, not sunburn. UVA also generates free radicals in living skin, which contribute to skin damage, wrinkling, and skin cancer.
Broad spectrum protection refers to protection over the full range of UVA and UVB waves. Originally, sunscreens were designed to protect against UVB rays, which cause sunburn but only account for a small portion of the full UV spectrum. UVB rays were once thought to be the only rays that could cause harm and UVA rays were thought to produce a "healthy" tan. We now know that UVA rays contribute to premature skin aging and some forms of skin cancer. A good broad spectrum sunscreen will protect against most of the UVA and UVB spectrum from at least 370nm to 280nm (see chart below). UVC is not a concern because it does not penetrate past the ozone layer and thus does not reach our skin. Note: zinc oxide sunscreen would even protect your skin from some UVC.
UVA: Long-wavelength solar rays of 320-400nm. UVA rays are not blocked by glass, clouds or the ozone layer and thus they comprise the vast majority of UV radiation reaching the Earth's surface. UVA rays are the same strength year-round and they penetrate
the skin more deeply (into the dermis, 2nd layer of skin), causing photo aging, actinic damage (wrinkled, leathery, variously pigmented skin), and contributing to skin cancers including melanoma. The active ingredient in Badger sunscreens, the mineral zinc oxide, offers excellent UVA protection.
UVB: Short-wavelength solar rays of 290-320 nm, mostly absorbed by the ozone layer. UVB rays have different strengths, depending on sun's location, and can be reduced by clouds. UVB rays penetrate only the epidermis (outer skin) causing sunburns and are considered to be the main cause of basal and squamous cell carcinoma, and are a significant factor in melanoma. Badger's active sunscreen ingredient, zinc oxide, is effective for all wavelengths of UVB rays.
UVC: Very short-wavelength solar rays of 200-290nm. UVC rays are blocked by the ozone layer atmospheric oxygen and do not reach the surface of the Earth in significant amounts. UVC is harmful to your skin (the next smaller wavelengths are X-Rays) but they are only a threat to astronauts and high flying pilots. Badger sunscreens are truly broad spectrum and even block UVC rays!
The US FDA Sunscreen Monograph lists seventeen allowed sunscreen active ingredients. Of these actives, two are minerals while the remaining fifteen are synthetic chemicals. Each active ingredient has its own unique spectrum of protection, ranging from full UVB protection to full UVA protection and everything in between. Only one chemical ingredient, Avobenzone, and one physical active ingredient, zinc oxide, offer full UVA protection. If using only chemicals, multiple active ingredients must be used to achieve full broad spectrum sunscreen protection. Zinc oxide is the only single active ingredient allowed here in the US that offers full UVA and UVB protection. See chart below.
Critical Wavelength and UVA Protection
The critical wavelength is the wavelength at which the sunscreen allows 10% of the rays to penetrate. A sunscreen with a critical wavelength over 370nm is considered by the FDA to provide excellent UVA protection. Badger sunscreens have critical wavelengths ranging from 379nm to 385nm, offering excellent protection from UVA rays! (See the chart below.)
UVA Protection Factor (UVA-PF)
This symbol is representative of the UVA Protection Grade (PA) or UVA Protection Factor UVA-PF, which is the result of the persistent pigment darkening (PPD) test. This test is conducted in-vivo (with human subjects) just as the SPF (Sun Protection Factor) test is conducted. This is the most rigorous form of UVA testing available worldwide. UVA-PF results are often labeled in three levels, PA+ being the lowest level of protection and PA+++ being the highest level of protection. Badger's Results: UVA-PF 5 for our SPF 15 (PA++) and UVA-PF 11 for our SPF 30 (PA+++).
According to the EU, broad spectrum protection is determined by the ratio of UVA to UVB protection. A product must achieve a ratio of 1/3 UVA protection in order to achieve the broad spectrum label claim. The UVA protection is determined by the UVA-PF test and then calculated based on the SPF of the product. A product that has 1/3 UVA protection in relation to the UVB protection may bear this symbol.