Sunscreen contains active and inactive ingredients. Active ingredients (active ingredients) protect the skin from UV damage, while inactive ingredients are mainly water and oil. According to the active ingredients, most sun protection products on the market can be divided into physical sunscreen and chemical sunscreens.

Physical sunscreen is to build a shield on the skin surface to block the reflected sunlight; The advantages are mild and non irritating, while the disadvantages are easy to turn white and sticky. Currently, there are only two physical sunscreen ingredients approved by FDA: titanium dioxide and zinc oxide.

Chemical sunscreen is equivalent to placing a sponge on the skin surface to absorb ultraviolet rays through chemical reaction to achieve sunscreen effect; The advantages are fresh texture and good absorption. The disadvantages are that it may be irritating to the skin - people with sensitive skin prefer physical sunscreen products and use chemical sunscreen products with caution.

Of course, there are also some products that contain two categories at the same time, namely the so-called "mixed sunscreen".