Sunscreen products often have SPF30 and SPF50 written on the product description, what is the signif

SPF 30+ means 300 minutes of effective sun protection (SPF 30 = 30 * 10 = 300 minutes). SPF 50+ means 500 minutes of effective sun protection (SPF 50 = 50 * 10 = 500 minutes).

SPF is the sun protection factor, which refers to the ratio of the energy required to produce the minimum erythema on the ** coated with sunscreen protection and the energy required to produce the same degree of erythema on the ** without any protection. The higher the SPF index, the greater the protection given to **.

SPF 30+ SPF 30 times.

SPF 50 + SPF 50 times.

SPF50 has a higher UV resistance index than SPF30.

SPF50+PA+++ indicates the productSPF

The first SPF50+ refers to the fact that the product can absorb more than 98% of UVB under laboratory conditions (the algorithm formula is (50-1) 50*100%=98%).

PA+++ refers to the delay of more than 8 times the time of being tanned.

Misunderstandings. Myth 1: SPF value.

The higher the sun protection, the better.

Sun Protection Factor. It's just a reference number, but it must also be considered according to the individual's skin type, sun reaction, color, activity and sweating.

Myth 2: The whole family should share a sunscreen product.

The choice of sunscreen needs to be "personalized", and family members should choose sunscreen according to their own needs.

The above content reference: Encyclopedia - Sun Protection Factor.

Sunscreen. The difference between SPF30 and SPF50 is that the length of sun protection is different, first of all, SPF is the sun protection factor, which is to fight against ultraviolet rays.

The difference in length of time if the SPF value.

The bigger, the stronger the protection**.

SPF15 = 150 minutes (UV resistance time), SPF20 = 200 minutes (UV resistance time), SPF30 = 300 minutes (UV resistance time), SPF50 = 500 minutes (UV resistance time).

Judging from the data, SPF30 is of course not as strong as SPF50 to resist ultraviolet rays, SPF30 is suitable for ordinary use, and SPF50 is suitable for outdoor use in the sun for a long time.

Precautions for sunscreen use

1. Choose sunscreen cosmetics to avoid causing allergies.

2. Choose a sunscreen with the appropriate coefficient.

3. Use time appropriately: do not apply sunscreen before going out.

4. The SPF value cannot be accumulated, and applying two layers of SPF10 sunscreen will only have the protective effect of one layer of SPF10.

5. It's best not to mix different brands of sunscreen at the same time.

6. Do not reduce the effect due to improper storage.

7. Cloudy day. You should also pay attention to sun protection.

Sunscreen SPF30+ means that the sun protection time is 30+.

SPF refers to the multiple of sun protection time for UVB, and the higher the SPF value, the longer the sun protection time. For example, it takes 15 minutes for skin to be reddened by ultraviolet rays without sunscreen, and the product with SPF30 states that the redness time is 15 min*30 = i.e., 15min*50=750min.

UVB refers to the medium-wave external line, which cannot penetrate the glass and will be attracted by the epidermis, resulting in redness and sunburn.

PA refers to the ability to protect against UVA, and the Japanese symbol is PA+, and the more PA++ and PA+++, the stronger the protection ability.

UVA stands for long-wave ultraviolet rays, which can be found all year round in any area, even on cloudy days, and can penetrate thin clouds and glass to reach the dermis of the human body to cause damage, which can lead to tanning and aging.

SPF30 means that if a person who does not have any sun protection measures will turn red after 20 minutes in the sun, when he uses SPF30 sunscreen, the appearance can be extended by 30 times, that is, after 600 minutes** will be red.

SPF50 means the same as above, but at a different time.

Of course, SPF50 has a higher sunscreen intensity, but it is not that the higher the intensity, the better the effect, and the daily boring chain life does not need to use sunscreen with such a high coefficient, and you should also pay attention to whether it is in line with your skin type.