- SPF: SPF stands for "Sun Protection Factor." According to WebMD, SPF is the ability of a sunscreen to block UVB rays, which cause sunburns, but not UVA rays, which can penetrate skin more deeply. The number, however, doesn't indicate how long a person can be outside in the sun before suffering from a burn. Some doctors argue that ditching your bottle of SPF 30 for a higher SPF may lead to a false sense of security about staying in the sun longer without reapplying. With the new regulations about labeling, the FDA has proposed a rule that would ban companies from labeling its sunscreen with an SPF of 50 or higher. Research suggests that there aren't any additional benefits once the SPF gets that high.
Find out what other sunscreen terms mean.
- Water-Resistant vs. Waterproof: A water-resistant sunscreen means that a sunscreen retains its SPF after swimming or sweating for a certain amount of time, whereas waterproof means that a sunscreen maintains its SPF up to 80 minutes after exposure to water. New FDA regulations state that "waterproof" will no longer be an allowed sunscreen claim since there isn't a sunscreen available on the market today that is 100-percent waterproof. Calling a sunscreen product "waterproof," "sweatproof," or "sunblock" falsely overstates its effectiveness, the FDA says. Under new regulations, sunscreens will only be allowed to be called "water-resistant" and will have to state how long they've been successfully tested to last when exposed to water.
- UVA vs. UVB: UVA rays account for 95 percent of the UV radiation reaching the Earth’s surface and are less intense than UVB rays. But, UVA rays penetrate the skin more deeply than UVB rays; can still cause skin damage through clouds and glass; and are the dominant tanning ray. UVB rays are mainly what cause sunburns. UVB rays also play a key role in the development of skin cancer and are most harmful between the hours of 10 a.m and 4 p.m. and between the months of April and October. Under the new FDA regulation, sunscreens labeled "broad spectrum" will have had to pass the FDA's test showing that the product protects against UVA and UVB rays equally.