What is the meaning of SPF and PA?

There are SPF numbers on sunscreen products, and there are many different SPF numbers. Do you know what SPF means?

What is the meaning of SPF?

SPF refers to the sun protection factor, or sun protection factor. SPF is the abbreviation of Sun Protection Factor, which indicates the sun protection effect of sunscreen products. It is determined based on the minimum erythema dose of the skin. The following value represents how many times the sunburn time can be extended. The higher the value, the better the sun protection effect.

What does PA mean?

The main function of PA is to prevent the skin from being tanned or aged, and it is an indicator of the degree of protection against ultraviolet rays. The effect of PA is divided into three levels: PA+, PA++, and PA+++, which respectively mean effective, very effective, and extremely effective. The more plus signs there are, the better the defense effect. The SPF value refers to the skin's sun protection time, and PA refers to the ability to resist tanning.

Misconceptions about using sunscreen

1. If your skin is good, you don’t need sunscreen

If you are only exposed to sunlight for a short time or occasionally, it will not have a major impact on your skin, such as redness, darkening, or peeling. However, if you do not take protective measures for a long time, your skin may develop pigmentation spots, photoaging, and increased wrinkles.

2. Apply sunscreen only once a day

Some sunscreen products contain photosensitivity ingredients, and their sunscreen effectiveness will decrease after being exposed to the sun for a period of time. There are also many sunscreen products that will become increasingly weaker in effectiveness due to dilution through sweat and other reasons, and often can only last for a few hours. It is recommended to reapply every 2 to 3 hours.

3. The higher the sunscreen factor, the better

The higher the product coefficient, the better. The higher the SPF of a sunscreen, the more sunscreen is added, and the greater the irritation to the skin, so you should choose according to the specific situation.