What does the value on the sunscreen mean?

The value on the sunscreen is the SPF of the sunscreen.

Sunscreen coefficient (SPF) refers to SPF, which is a test index to measure the defense ability of sunscreen products against ultraviolet UVB in the sun, and indicates the level of sunscreen efficiency that sunscreen products can exert. According to the minimum erythema dose of skin.

People who look forward to staying indoors for a long time can choose SPF 10 and PA+ sunscreen products; Often outdoors, easy to tan, people who are sensitive to strong light can choose SPF20 or so, pa++；+; +; Working in the hot sun for a long time or going to the seaside to play, it is best to choose SPF30 or so, PA+++ strong sunscreen products. Use SPF 15-25 and PA++ daily.

Extended data:

The higher the SPF, the better.

When buying sunscreen, people should first pay attention to the sun protection coefficient. There are two general sun protection factors, SPF (sun protection factor) and PA (protection factor of UVA), but the higher the factor, the better.

SPF is a sunscreen factor of UVB. Experiments show that products with SPF >: 30 can provide enough protection to the skin when used correctly, so in 2005, China no longer allowed to indicate SPF greater than 30 for sunscreen products, and all SPF greater than 30 were expressed as SPF 30+ to avoid misleading consumers.

PA is the protection coefficient against UVA, and there is no specific index at present, only divided into+,++and++. PA+ can protect for about 4 hours, PA++ can protect for about 8 hours, and PA+++ is super protection.

The sun protection coefficient is measured in the laboratory in strict accordance with the use requirements and thickness. In practical use, it is difficult for ordinary people to apply sunscreen to a sufficient thickness, and it will also cause loss because of sweating and wiping their faces. Therefore, the correct use of sunscreen is far more important than coefficient. In addition, sun protection around eyes and lips is also very important, so you need to choose a special sunscreen.

References:

Baidu encyclopedia-sun protection coefficient

People's Network-Do you really protect yourself from the sun? Dermatologists teach you how to use sunscreen.

People's Network-Sunscreen needs to be applied every day. The higher the SPF, the better.