What is the PA index of sunscreen?

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PA stands for UVA (UVA is the effect of aging skin**) and is a Japanese sun protection index measure that measures the stability of persistent melanin deposits (PPD) after 2-4 hours of sun exposure. The more PA protection is PA+, PA++, and the more PA+++ words, the better the effect of UVA prevention and the longer the effective protection time.

PA+: Indicates that it is effective, and the protection time is about 2

4 hours. PA++ means quite effective, with a protection time of 4 to 8 hours.

PA++ means quite effective, with a protection time of 4 to 8 hours.

The PA and SPF of sunscreens have different sun protection functions, either individually SPF or in combination.

Choosing a sunscreen is about choosing drops based on the season and the intensity of UV rays.

Algorithm of the index: SPF1 = 15-20 minutes.

Pa+ = 4 hours.

That is, in the case of SPF12, you can protect yourself from the sun for 3-4 hours.

Now the index is between 12 and 15, and it is enough to increase the index as the daylight increases.

Remember: the greater the sun protection index, the greater the damage to the **, if you only work indoors, you can also use the sunscreen isolation cream to minimize the damage to the **.

Calculate the SPF value. Generally speaking, the higher the SPF, the greater the protection. In general, people with normal skin tones should have SPF 8 to 12; **For fair-skinned people, it is recommended to choose a sunscreen with SPF30; For those who are allergic to light, it is advisable to choose an SPF between 12 and 20.

15 to 30 is OK, and the sunscreen effect is good in summer. Maximum value of 30.

SPF. PA+++ refers to the effective sunscreen time of sunscreen, which means that it can delay the tanning time of the skin by more than 8 times. "PA+" stands for sunscreen.

It can delay the tanning time of the skin by 2-4 times, and "PA++" means that the sunscreen can delay the tanning time of the skin by 4-8 times.

The significance of SPA in sunscreens.

PA refers to the index that can block the UVA long wave in the sun, and in sunscreen products, it represents the level of sunscreen to delay the tanning of the skin, that is, the strength of suntan. Usually this index is divided into three grades, namely: PA+, PA++, PA+++ The effective sun protection time increases in turn, which means that the more plus signs after PA, the better the tanning effect.

For example, SPF20 and PA++ sunscreen show that this bottle of sunscreen can effectively protect against the sun for 400 minutes, and it is quite effective against UVA's defense. The more PA+++ sunscreen is, the better, and the more it means that the longer it will prevent tanning, the higher the degree of tanning, the more ultraviolet rays it will block, and the less damage it will do to the human body.

Generally, in daily life, there is no need to use PA+++ more sunscreen for a long time, it is enough to use PA++, and then extend the sunscreen time by reapplying it after the time, if you are traveling or experiencing long-term exposure to the sun, it is best to use PA+++ sunscreen.

SPS is the sun protection flutter retown factor. PA+++ means to extend the tanning difference and the dark time by 8 to 15 times.

SPF and PA are the two major indices of sunscreen products. SPF is called sun protection factor, which is an index to evaluate the ability of sunscreen cosmetics to prevent redness. PA is the UVA sun protection factor, which is an index to evaluate the ability of sunscreen cosmetics to prevent ** from being tanned.

The PA coefficient is represented by "". "The more +, the stronger the tanning ability.

PA+, which means that the use of this sunscreen cosmetics can prolong the tanning time by 2 to 3 times; PA++, which means that the tanning time is extended by 4 7 times; PA+++ means to extend the tanning time by 8 to 15 times; When the tanning time is extended by more than 16 times, it is a big problem for pa+++** tanning, and it is also the most direct target of many people's sun protection, so pa is also very important, especially on days with strong ultraviolet rays, it is necessary to use products with a higher pa coefficient.

How to protect yourself from the sun in summer

1. Wear sunscreen.

Applying sunscreen can have a sunscreen effect, and it can also protect**, reduce the damage of ultraviolet rays**, and reduce the appearance of melanin. When you are outdoors or go out to work, you should apply sunscreen about half an hour in advance, and sunscreen has a certain resistance effect on ultraviolet rays.

2. Wear sun-protective clothing.

There are a variety of sunscreen clothing on the market, which can help resist some UV rays and reduce the risk of tanning or sunburn. However, there is one thing that everyone should pay attention to, it is very important to choose sunscreen clothing, and wear sunscreen clothing with strong colors, so that the refraction effect on ultraviolet rays is better.

3. Wear a sunscreen hat.

Everyone should bring a sunscreen hat when going out, a sunscreen hat can not only reduce the best sunburn, but also avoid problems such as ultraviolet allergies.

The above content reference: Encyclopedia - Sunscreen.

Between 30 and 50, and then the lead is too high, and it's best to make up every four hours.

If it is summer and the place of living is close to unsheltered areas, you should choose SPF30, PA++ is fine.

But to go to the beach for swimming or vacation, you should choose SPF50, PA++ PA+++ is appropriate. A full-body repair should also be done in the evening.

Daily home life should also protect from the sun, choose SPF15-20, PA++ sunscreen. Stick to an hourly spray of moisturizing spray.

SPF is the sun protection index, or sun protection factor, which mainly refers to the protection index of the product against UVB rays, the higher the SPF value, the stronger the effect of UVB protection.

Each unit of the SPF value represents the ability to stay in sunlight for 15 minutes without UVB damage.

For example, if you will have erythema after 15 minutes in the sun, after using a sunscreen with a spa of 20, the time for erythema can be extended to 15*20=300 minutes, that is, a face that would have been red in 15 minutes can be protected by this bottle of sunscreen for 5 hours.

PA is the tanning index, which mainly refers to the protection index of the product against long-wave ultraviolet rays, and the "+" indicates the product's defense ability. "The more + signs, the greater the value of PA, and the stronger the protection against UVA rays.

Specifically, PA+ means that it can delay the tanning time of the skin by 2-4 times, PA++ means that it can delay the time of 4-8 times, and PA+++ means that it can delay the time of tanning by more than 8 times.