Firstly, apply sunscreen cosmetics evenly on the exposed parts of the skin; secondly, the amount must be sufficient, and a layer of sunscreen cosmetics must be seen on the skin surface, then the sunscreen effect stated in the instructions can be achieved.
SPF (skinProtectionFactor human skin protection index) represents the ability of sunscreen products to protect against sun protection and absorb ultraviolet rays. SPF is an index measured after applying 2 mg of sunscreen cosmetics per square centimeter of skin. Each unit of the value of SPF means that it can stay in the sun for 15 minutes without being harmed by B ultraviolet (U-VB). For example, SPF15 means that after applying SPF15 sunscreen, it can stay in the sun for 15×15=225 minutes, so that the skin is not damaged by ultraviolet B.
According to the skin color and the reaction to sunlight, the skin is divided into type Ⅰ-Ⅶ. Professor Zhou Hua said that most Chinese skin types are type IV, and a small number are type III and type V. Type IV skin is easy to tan but not easy to get sunburned. Therefore, Professor Zhou Hua recommends that people with type IV skin choose sunscreen cosmetics with SPF of 6-8.
At present, there is a tendency to one-sided pursuit of high SPF at home and abroad. The reason is that when consumers do not apply in sufficient amount according to the use requirements, sweat or immerse in water, high SPF sunscreen cosmetics can also provide considerable protection, while low SPF is powerless. However, sunscreen cosmetics with high SPF are highly irritating to the skin and costly. On the ground, the intensity of ultraviolet A (UVA) is more than 30 times higher than that of ultraviolet B (UVB), and many sunscreen cosmetics only have a protective effect on UVB. After using sunscreen cosmetics, people tend to spend more time outdoors, and the result is accepted More VBA exposure than usual. New research shows that UVA also has a damaging effect on the skin. Therefore, it is good to choose broad-spectrum sunscreen cosmetics that prevent both UVB and UVA. For example, choose high-SPF sunscreen cosmetics, which must be broad-spectrum. Generally speaking, use SPF15-25, UVB/UVA protection ratio not less than or equal to 2.5 full sunscreen cosmetics.
The above is all about how to use sunscreen cosmetics correctly. If there is anything you don’t know, you can contact us directly and we will serve you wholeheartedly.