Sunscreens are products which help prevent the sun’s ultraviolet radiation from damaging the skin. Sunlight consists of two types of ultraviolet radiation: UVA and UVB, with varying sunscreen protection.
Ultraviolet radiation is part of the sun’s light spectrum and is invisible to the naked eye. Generally speaking, UVA (the longer wave UV ray) causes skin aging and lasting skin damage, and UVB (the shorter wave UV ray) causes sunburns and skin damage. Both can increase skin cancer risk, though the risk associated with UVB rays is larger.
Understanding the Labels
The Sun Protection Factor, shortened to SPF, is a measure of a sunscreen’s protection of UVB rays. Products with a SPF between 30 and 50 are recommended (SPF 15 blocks out 93% of UVB rays, while SPF 30 and 50 block out, respectively, 96.7% and 98% of UVB rays). The numbers work like this: if you can typically stay out in the sun for 10 minutes before getting a sunburn, applying a SPF 30 product (properly) should allow you to stay in the sun 30 times longer without getting burned. It’s obviously not an exact science, since the amount of UV rays that reach us depend on a variety of factors.
The + sign sometimes used means “more than” – so a label of 30+ means a product should test higher than 30.
PA is the protection grade of UVA rays and contains three levels of protection: PA+, PA++ and PA+++. The lowest protects sensitive skin against low to medium UVA radiation, the medium provides moderate UVA protection and the highest protects against very strong or direct UVA radiation.
Broad-Spectrum or Multi Spectrum
This label means the product offers protection for both UVA and UVB rays.
Though the protection level is important, the application is even more so, since a sunscreen must be applied liberally to achieve its labeled protection. Most people do not use enough sunscreen to fully protect their skins, which may result in protection far lower than labeled.
Another thing to take notice is that water-resistant does not mean waterproof: even though a product may be resistant to water, that does not mean it will stay budgeproof and offer the same protection it did before a swim. Reapplying the product after swimming or towelling, or after two hours, is important to guarantee protection.