is summer sunscreen one for everyone? Sunscreen is a product that is necessary for delicate pig girls in summer, but many people will have such a question: how long is the shelf life of summer sunscreen generally? Can last year's sunscreen still be used?
How long is sunscreen effective after opening
Although the shelf life of the sunscreen bottle is generally 3 or 5 years, the sunscreen is generally effective within one year after opening. The sunscreen after opening has little effect after being placed in the second year. Its components will be oxidized or volatilized when contacting with oxygen. It is also easy to breed bacteria and deteriorate. The plastic bottle itself will degrade, so the sunscreen will be unsealed It's better to use it up in a year.
Sunscreen for the next year after opening
The sunscreen placed in the second year after unsealing will reduce its sunscreen composition, which is difficult to achieve the expected sunscreen effect. If the sunscreen is reluctant to be discarded in the next year, it can be used to wipe the hands and feet of the body, because the skin of the body is not as thin as the face skin, not so sensitive, and it has a certain sunscreen effect on the body, but it is one lower than the marked sunscreen value Some.
Expired open sunscreen cannot be used
After the opening of the sunscreen, if the shelf life has passed, do not continue to use it. This is because the effectiveness of the sunscreen contained in the opened sunscreen will be greatly reduced after the expiration of the time limit. Basically, it can not play the sunscreen effect marked above. After using, it can not achieve the desired sunscreen effect, and it is easy to be sunburned, tanned, or even hurt the skin, resulting in the skin becoming sensitive. Some people will also Causes dermatitis.
It is better to use 'fresh' skin care products and cosmetics. If the sunscreen is unsealed, no matter how expensive it is, it will not achieve the expected effect if it exceeds the optimal service life, and it will also breed bacteria, which should be discarded. In addition, no matter sunscreen, water, milk or some cosmetics, they should be kept away from light at low temperature, because if the temperature is too high and the sunlight is direct, it is easy to deteriorate, especially for cosmetics with chemical substances, whose deterioration speed is faster.