Is it really necessary to reapply sunscreen after it has been opened for a certain period of time?

Although we can wear cool and comfortable summer clothes under the scorching sun, the burning ultraviolet rays force us to give up the idea of ​​going out. Even if we want to go out, we must be fully armed. As a must-have item in summer, do you know the effective period of sunscreen?

How long should you wait before using the sunscreen after opening it?

Sunscreen should no longer be used after one year of opening. Generally speaking, the shelf life of sunscreen is 3-5 years. But why can sunscreen only be used for one year after opening? This is because after the opened sunscreen comes into contact with the air, its ingredients react with oxygen and become oxidized or volatilized, which may deteriorate. Not only will the sun protection effect be greatly reduced, but it will also cause unnecessary trouble to the skin.

Can I still use the sunscreen I didn't use up last year?

Some hoarding fairies will stock up on sunscreen products in advance. If the sunscreen is unopened, you can continue to use it, but pay attention to the shelf life. If the sunscreen has been opened, it is not recommended to use it on the face, but it can be used on the limbs or neck. And before applying, it is best to test behind the ear to see if a deterioration reaction has occurred.

What to do if your sunscreen is expired

It is best not to use expired sunscreen. If it is an unopened sunscreen that has not been expired for a long time, it can be used to apply on the feet. Because the skin on the body is much thicker than the skin on the face and not as sensitive, there is no problem with using it in moderation.

How often should you reapply sunscreen?

When going out, sunscreen needs to be reapplied every three hours. If you don’t reapply it in time, you are likely to get sunburned or tanned. Especially when the ultraviolet rays are strong, you can increase the frequency of reapplication. You should reapply sunscreen at least twice indoors or in places with weak ultraviolet rays. Also, please note that it is best to wipe off sweat stains before reapplying.