What is the shelf life of sunscreen?

The shelf life of sunscreen is usually two to three years. Most people think that as long as it is not opened within the shelf life, it is fine and should be used up within one year after opening. This is a very wrong idea.

Sunscreen is exposed to air and sunlight over a large area of ​​the face, and its ineffectiveness rate reaches the maximum, so there is the concept of reapplying sunscreen. After the sunscreen is opened, it will also be exposed to oxygen and sunlight in the bottle, but the ineffectiveness rate is much slower. Therefore, if you really want to achieve the SPF value indicated on the sunscreen , you must use it within six months after opening.

Since the sunscreen ingredients in sunscreen are unstable, they will always be unstable no matter where they are. Even if you don't open it, it will become ineffective sooner or later. It's just a matter of time. The 2- year shelf life of sunscreen means that after 1 year and 364 days, the sunscreen effect is almost zero . It doesn't mean that the SPF value will be the same during these two years . Usually, any sunscreen product, even if it is unopened, will have a significant reduction in sunscreen effect after 1 year from the production date .

When buying sunscreen, be sure to choose fresh sunscreen with a production date of less than six months, and use it up within six months after opening the bottle.