How to judge whether sunscreen has formed a film? Will the sunscreen be rubbed off after it forms a film?

Sunscreen film formation refers to the fact that some time after using the sunscreen, the sunscreen in the sunscreen will form a tight barrier on the skin surface that can block UVA and UVB in the sun. Generally, the sun protection effect will be better after the sunscreen forms a film; if the sunscreen does not form a film, or this film is damaged, the sun protection effect will be greatly reduced. So, how do you determine whether sunscreen forms a film?

How to judge the film formation of sunscreen

After applying the sunscreen, you can wait for a while and then look in the mirror. If you find that the surface of your skin looks shiny, as if there is a layer of film that is not thick and feels a little slippery when you touch it with your hand, then it means that the sunscreen has formed a film.

How long does it take for sunscreen to form a film?

Different sunscreens take different amounts of time to form a film. Some sunscreens form a film quickly, maybe only 3-5 minutes, but some sunscreens form a film very slowly, maybe 10-30 minutes. You need to use sunscreen by yourself to make sure. Generally, before going out or applying makeup on your face, you have to wait until the sunscreen forms a film, otherwise the sun protection effect will be poor.

Will sunscreen be rubbed off after it forms a film?

Sunscreen may be rubbed off after it forms a film. After the sunscreen forms a film, it may be rubbed off if it encounters water, oil, sweat, or external friction, and the sunscreen will generally become ineffective after 2-3 hours. Therefore, it is recommended that outdoor workers reapply sunscreen every 2-3 hours.

Does good waterproofing mean good film-forming effect?

Sunscreen with good film-forming effect must be waterproof. You can do a test on the back of your hand. Apply sunscreen and spray water with a spray bottle. If water droplets form, it is waterproof. If it melts, it is not waterproof. Good waterproofness is only part of good film formation. It cannot be said that good waterproofness means good film formation. But it is not waterproof at all after melting, and the film-forming effect is definitely not good. As a sunscreen, the primary issue for whether the sunscreen has a good film-forming effect is that it is not easy to lose. Film formation may also affect leakage, that is, the sunscreen is absorbed into the skin, while sunscreen does not need to be absorbed. If it is absorbed by the skin, it will cause you to age faster the more you apply sunscreen.