What does SPF mean? What is the difference between one sunscreen and another? Are chemical or mineral filters better? Here is how to choose the right sunscreen.
Applying sunscreen should be automatic, yet every year new products come out with more innovative technologies and filters that protect the oceans from pollution. At the time of choice and application doubts arise as to which routine is best to avoid sunburn and defend the skin from premature aging.
High-protection sunscreens are not all the same. Let’s talk about SPF (sun protection factor) 30 and 50, which are those recommended by dermatologists. The number indicates the ability of sunscreens to protect against UVB radiation, which is the radiation responsible for sunburn. A good product also always protects against UVA rays, which penetrate deeper, and are present even when the sky is cloudy and cause skin aging. That is why antioxidant actives, such as vitamin E, are also always present in sunscreens.
SPF 50 or 30?
An SPF 50 sunscreen protects 98 percent from UV rays, while SPF 30 would stop about 97 percent of the sun’s rays. There is no such thing as a full-screen protection factor. SPF 50+ undoubtedly protects more with a value that is theoretically higher, but the differences are minimal. Sun protection factors above 50 do not substantially increase UV protection.
Chemical or mineral (physical) filters?
Chemical filters are synthetic filters that absorb radiation and scatter it as heat. Their impact on the skin and the environment depends on the type of filter used (the Hawaiian Islands, for example, have officially banned creams with particular sunscreens such as octinoxate and oxybenzone, because they are considered harmful to the marine ecosystem). Their texture, by virtue of cosmetic research, is often very light, fluid, and invisible on the skin.
Physical filters such as zinc oxide and titanium oxide can reflect, diffuse, and absorb UV rays. The skin may appear whitish in the visible area of light precisely because they constitute a physical filter.
Often this division is not clear-cut because physical and chemical filters are used in combination with products to increase the effectiveness of protection.
The rule that applies to all sunscreens: twelve months after opening, as indicated by the PAO (Period After Opening), sunscreens are no longer safe and stable, and therefore their degree of protection is no longer reliable.
What about the city SPF?
City SPFs protect the skin from UV rays and those factors such as pollution that cause premature aging and cell oxidation. They are not the same as day creams or foundations on which the SPF is listed because the filters used are not comparable to sunscreens.
Compared with sunscreens that are more suitable for the beach or the mountains, city SPFs are distinguished by a comfortable texture that is also ideal as a primer before applying make-up and has a mattifying effect.