In the face of the summer heat, sun protection has become a must-do homework for women every day, because the damage caused by UV rays to the skin is not simply a tan, it can also damage your skin, leading to sunburn and skin aging. So, how can you do a good job of sun protection? Let’s take a look at the harm of UV rays on skin: 1. Too much UV rays on skin will increase melanin synthesis, which can lead to pigmentation, such as dark spots, freckles, chloasma and other kinds of pigmentation increase, increase, and become deeper. 2.Proliferation of keratin-forming cells will lead to thickening of skin, relaxation, roughness and wrinkles, capillary dilation and red spots. It also decreases the immune function of the skin and forms skin cancer or precancerous lesions. Therefore, the key to protecting the skin, preventing skin aging and preventing skin cancer is to prevent the damage of UV rays from the sun. Look at the sunscreen principle 1, physical sunscreen As the name implies, it is the use of physics to protect against the sun. The atomic particles of this sunscreen are flaky and when applied on the face, it is like a mirror, reflecting the sunlight and achieving the purpose of sun protection. Titanium dioxide and zinc oxide are two minerals that absorb UV rays. The finer and more uniform the particles of titanium dioxide and zinc oxide, the better the sunscreen effect and the better the transparency of the sunscreen product. If the particles in a skin care product are large, and the large particles have the effect of scattering visible light, they will appear whitish when applied to the skin. And the finer the particles of minerals are, the greater their cohesive effect will be. Therefore, ultra-fine microparticles are produced while coating them with a protective film of silica and aluminum trioxide, which helps make the ultra-fine particles less cohesive. Now, the use of titanium dioxide and zinc oxide in sunscreen skin care products has been increasing. 2, chemical sunscreen Use the principle of absorption to sunscreen, often light-transmitting substances, can absorb ultraviolet light, so that it is converted into molecular vibration energy or heat to achieve the effectiveness of sunscreen. After applying to the face, atoms absorb sunlight to prevent the sun from touching the skin. The most common UV chemical absorbing substance is PABA (para-aminobenzoic acid). The sunscreen factor (SPF) is the level of sunscreen effectiveness that sunscreens can play, so that consumers can choose sunscreens with different SPF values according to their age, nature of work, lifestyle, body perspiration, skin condition, skin tone, skin’s photoreactivity, etc. The SPF value of sunscreen is 8-12 for people with general type of skin, and for people who are sensitive to sunlight, SPF value between 12-20 is appropriate; SPF value for indoor office workers can be below 15; in the field and seaside, SPF value should be above 30, and outdoor workers wash with SPF value of 20-25. Many people think that the higher the SPF value of sunscreen, the more sun protection, in fact, the higher the SPF value The higher the SPF value of the sunscreen, the higher the sunscreen component – UV antagonist contained, which in turn interferes with the normal breathing and metabolism of the skin, easy to ho into the hand hole Yangsei, oily skin. 2, master the application time sunscreen and general skin care products, not applied to be effective, but need a time to be absorbed by the skin therefore, should be applied to the sunscreen 20 minutes before going out. 3, apply the appropriate amount of sun protection factor (SPF value) will not be cumulative, that is, if you apply two layers of SPF value of 10 sunscreen, and only apply a layer of SPF value of 10 sunscreen effect is the same. The amount of sunscreen usually applied to the skin is 2 mg per square centimeter, in order to achieve the desired sunscreen effect. 4, different skin types buy different Before buying sunscreen, first in the inner wrist smear test, within 10 minutes if the redness, swelling, pain, itchy phenomenon, indicating that the skin has an allergic reaction to this sunscreen, you can choose a lower sun protection index products. Oily skin and face with acne, should choose a strong penetration of water-based, oil-free formula sunscreen, after using a fresh, non-greasy, non-clogging pores. The actual skin is also a lot more comfortable to use. 5, SPF value can not be cumulative coated with two layers of SPF10 sunscreen, only one layer of SPF10 protection effect can not go out before applying sunscreen. Sunscreen and general skin care products, like, need a certain amount of time to be absorbed by the skin. So it should be applied 10-20 minutes before going out. 6, sunscreen is not applied on the effective but to achieve a certain amount to play the effect. Usually the amount of sunscreen applied to the skin is 2 mg per square centimeter to achieve the proper sunscreen effect.