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How long is the shelf life of sunscreen? Can last year's sunscreen still be used this year

For sunscreen, almost all female friends are familiar with it. In fact, they have to do a good job of sunscreen all year round. So how long is the shelf life of sunscreen? Can the sunscreen you bought last year still work this year?

1. How long is the shelf life of sunscreen

Will you buy more sunscreens when you meet with good sunscreens? Can you continue to use the sunscreens you bought last year? Beauty bloggers have a saying that last year's sunscreens are best not to be used, because the sunscreen effect will be greatly reduced, and it may also cause allergies & hellip; & hellip; is the money we hoard 'wasted'

Recently, Wang Baoxi, chief physician of plastic surgery hospital of Chinese Academy of Medical Sciences, said in the live broadcast of "good doctor of the people" client popular science consultation that sunscreen that has not been opened can be used normally within the validity period as long as it is well sealed and properly stored. 'for sunscreen that has been used, after another year, the matrix may have changed, so it is not recommended to continue to use it. '

Wang Baoxi explained that the physical protective ingredients in sunscreen, such as zinc oxide and titanium dioxide, will not deteriorate or fail over a long period of time. However, other ingredients in sunscreen may deteriorate due to high temperature or contact with the air, causing serious bacteria breeding and deterioration.

You can pay attention to the storage method and expiration date indicated on the package of sunscreen. It is generally required to keep it in a cool and dry place, and the bottle cap should be tightened after each use. 'some sunscreens will print a picture of the open bottle on the package, and the words such as 12m or 6m will be written under the picture, which means that the shelf life after opening is 12 months or 6 months. '

Wang Baoxi stressed that when it is found that the texture and state of sunscreen are different from those when it was first used, it is necessary to stop using it and buy new sunscreen to avoid skin allergy or inflammation caused by deteriorated sunscreen.

2. Precautions for use of sunscreen

How long to use sunscreen

You can't use it before putting on makeup, and you can't apply sunscreen just before going out. Like other skin care products, sunscreen needs a certain amount of time to be absorbed by the skin, so you should apply sunscreen 10-20 minutes before going out, and 30 minutes before going to the beach.

Use enough

Sunscreen is not only effective when applied, but also effective when applied in a certain amount. Usually, when the amount of sunscreen applied on the skin is 2 mg per square centimeter, the sunscreen effect can be achieved. It should be noted that the SPF value can not be accumulated, two layers of SPF10 sunscreen, only one layer of SPF10 protective effect.

Don't mix different brands of sunscreen

Mixed use will increase the possibility of skin allergy. The ingredients of different brands of sunscreen are inconsistent. If they are mixed and overlapped on the skin, the ingredients may interfere with or repel each other, reduce the sunscreen effect, and even cause skin allergy.

Do not use deteriorated sunscreen cosmetics

Sunscreen may be less effective if exposed to heat or direct sunlight for a long time. Do not use deteriorated sunscreen cosmetics, because it not only reduces the sunscreen effect, but also is more likely to irritate the skin.

Pay attention to the blind spots

When you apply ordinary sunscreen products, you will generally avoid eye and lip skin as well as ordinary skin care products. Therefore, the eye and lip skin has become a "sunscreen dead angle". Eye cream and lipstick with sunscreen value are necessary. Do not worry that these things will give skin pressure to the sensitive part of the sensitive part, because it must be at least more than the pressure exposed to sunlight and the ability to withstand ordinary sunscreen products. It's small. But the best choice is physical sunscreen.