1, physical barrier: mainly uses the reflection of some inorganic substances on ultraviolet rays to reduce the harm of ultraviolet rays to the skin. Such as zinc oxide, titanium dioxide, talcum powder and the like.
2. Chemical absorbent: mainly an absorbent that absorbs ultraviolet rays, and converts the light energy absorbed from ultraviolet rays into heat energy or harmless visible light to prevent sunburn by ultraviolet rays. For example: amino benzoic acid (PABA) derivatives, o-aminobenzoic acid derivatives, cinnamates, salicylates, camphor derivatives, etc.
3. Natural sun protection: it has the effects of preventing ultraviolet rays and scavenging free radicals, achieving the effects of repair and anti-aging, and has high safety. For example: Scutellaria baicalensis Georgi, Blackberry, Pomegranate, Aloe Vera, Green Tea, etc.
For sunscreen products, we are most concerned about the sunscreen effect of the products. How to judge the sunscreen effect of products requires everyone to understand the meaning of relevant signs on the packaging label of sunscreen products. There are two signs related to the sunscreen effect on the sunscreen label, one is SPF value and the other is PA grade.
SPF value is the performance index of sunscreen to protect skin from sunburn, and it is also the evaluation of UVB protection effect, which is called sun protection coefficient or sun protection coefficient.
PFA value reflects the defense effect of the product against UVA.
Among all sunscreen products, Japanese sunscreen has the best skin feeling, unlike European and American sunscreen products, which are thick and greasy. The skin feels soft and smooth, and there is almost no burden. Of course, excessive pursuit of skin feeling will sacrifice part of sunscreen ability, resulting in a higher sunscreen index marked by Japanese sunscreen products than the actual one. Compared with Japanese cosmetics, European cosmetics and American cosmetics, Korean cosmetics started late and lacked overall technical strength, so there were few comments on domestic cosmetics.
How to choose sunscreen products correctly
1, choose sunscreen according to your skin.
The sebum secretion of oil skin is greater than that of other skin types, so when choosing sunscreen, try to choose a light and non-greasy sunscreen. Nowadays, many people recommend the use of Japanese correction liquid sunscreen for oil skin, mainly because this sunscreen is waterproof and sweat-proof, and it is an option for oil skin. After the silicone oil inside evaporates, it will dry and present a matte texture.
The sunscreen of dry skin is mainly moisturizing. Choosing a sunscreen with emulsion or cream texture will have more moisturizing effect than ordinary sunscreen, which contains effective ingredients with moisturizing effect such as hyaluronic acid, ceramide or vegetable oil, which can help dry skin to move in the sun for a longer time.
Sensitive muscles should choose skin care products on the premise that the skin will not be allergic, so it is best to use pure physical sunscreen when purchasing sunscreen for this kind of skin. If you can afford it and don't need to be exposed to the sun for a long time, you can choose some biological sunscreen.
When choosing sunscreen, it is best for mixed skin to be fresh, breathable and not greasy.
Step 2 choose sunscreen according to the scene
SPF is a sunscreen index mainly aimed at UVB. Relatively speaking, the larger the value, the stronger the degree of sun protection. Generally, office workers who only sunbathe on the way to work and on the way can choose sunscreen below 15. However, the recommended sun protection index for outdoor play and seaside swimming is above 30.
Step 3 give it a try
In fact, the easiest way to know whether you are suitable for this sunscreen product is to test it. You can test it on your wrist before you buy it. If the skin becomes red, swollen, itchy and painful after 10 minutes, you are allergic to this sunscreen product, and you can choose a product with a lower index.
I hope the above answers are helpful to you.
Physical barrier
The physical barrier mainly uses some inorganic substances to scatter or reflect ultraviolet rays to reduce the harm of ultraviolet rays to the skin. Such as kaolin, zinc oxide, talcum powder, titanium oxide and new organic powder.
They mainly form a barrier on the skin surface to prevent ultraviolet rays from directly irradiating the skin, but this substance has the disadvantages of large dosage and poor sunscreen effect. Excessive use is easy to block pores and lead to new skin diseases and other adverse consequences.
chemical absorbent
Chemical absorbent refers to the ultraviolet absorbent that can absorb ultraviolet rays. The light energy absorbed by their molecules from ultraviolet rays is equal to the energy needed to cause "photochemical excitation" of molecules, so that the light energy can be converted into heat energy or emitted by harmless visible light, thus effectively preventing the skin from tanning and sunburn caused by ultraviolet rays.
① p-aminobenzoic acid (PABA) derivatives are the earliest used ultraviolet absorbers, and are effective irritants to the skin as UVB absorbers.
2. O-aminobenzoate derivatives have the ability to prevent UVA and UVB rays, and are effective ultraviolet absorbers with low price, low absorption rate and no irritation to skin.
(3) Cinnamate has high absorption rate and is widely used.
P-Paso MCX (octyl methoxycinnamate) is the most common sunscreen in the world at present, which has excellent ultraviolet absorption curve, good safety and good solubility in oily raw materials, and is almost an ideal sunscreen. 4- methoxycinnamic acid -2- ethylhexyl ester is the most commonly used UVB absorbent.
(4) salicylate has poor sunscreen effect, low price, simple preparation process and low toxicity, and can be used in combination with other sunscreens.
⑤ Benzophenone compounds and benzophenone methyl ketone sunscreens have a strong absorption effect on almost the whole ultraviolet region. This sunscreen cream has high thermal stability and light stability, but it is unstable to oxidation, so antioxidants must be added to the formula when preparing colored cosmetics. This sunscreen has good affinity to skin and mucosa, no photosensitive reaction and low toxicity.
⑥ Camphor derivative, 3- phenyldecyl camphor can effectively absorb the ultraviolet rays in the sunburn range, but it can completely pass the ultraviolet rays in the tanning range. It can be used in various tanning agents and sunscreens with stable storage, no irritation, no photosensitivity and invariance, and low toxicity, but it is not easily absorbed by the skin.
Sun protection factor (SPF value is the ratio of the energy required to produce the minimum erythema on the skin protected by sun protection products to the energy required to produce the same degree of erythema on the unprotected skin. ), the higher the shielding effect on sunlight ultraviolet rays, the better, but the higher the concentration of organic ultraviolet absorbent added, the greater the possibility of skin allergy. In general, you can use sunscreen with SPF of 15, and the maximum SPF should not exceed 30.
Natural sunscreen
Natural sunscreen cream has the functions of preventing ultraviolet rays and scavenging oxygen free radicals, thus achieving the effects of repairing skin and delaying aging, and has good safety. Plants with natural sunscreen function include aloe, green tea, Scutellaria baicalensis, Lithospermum, Blackberry, Lapis lazuli, pomegranate and so on.
Distinguish sunscreen from different manufacturers
In fact, it is more important to distinguish between physical sunscreen and chemical sunscreen.
Titanium dioxide and zinc oxide are two common sunscreens in physical sun protection, which can isolate UVB and short-wave UBA well, but have relatively weak protective ability against long-wave UVA which is easy to cause photoaging. Moreover, physical sunscreen is mainly for surface safety, which is not a good choice for sensitive skin and acne skin.
Chemical sunscreen is more irritating because it forms a film on the skin surface, but its metabolism is in the skin, so it is best to avoid this choice for sensitive muscles and acne skin! On the contrary, oily skin and oily skin are more suitable
There is also a kind of physical and chemical mixed sunscreen, which has both physical and chemical sunscreen, which can protect the skin from ultraviolet rays more comprehensively. It can be seen that both dry skin and dry skin can choose this kind of sunscreen products.
1. From the big classification, all kinds of sunscreen liquid foundation/cream, sunscreen powder, etc. It is also a pure physical sunscreen, except that it is a pure physical sunscreen product. Other sunscreens and sunscreens are mostly chemical sunscreens, or both physical and chemical sunscreens;
Some new products this year have added functions other than sun protection. For example, Olay sunscreen SPF 30 pa++ can exfoliate and repair damaged skin, and Clarins anti-wrinkle sunscreen SPA30 can effectively resist free radicals. In addition, all creams and lotions containing SPF are also chemical sunscreen.
2. Another way to distinguish, of course, is to regard it as a division. Physical sunscreens are mainly titanium dioxide (TiO2) and zinc oxide (ZnO); Chemical sunscreen is hard to remember. The most common is the Mexo-rylXL full-wavelength ultraviolet isolation system patented by L 'Oré al Group, which has been adopted by L 'Oré al Paris, Vichy, la roche-posay, Lancome, biotherm, HR and other brands.
If memorizing these chemical terms is too annoying, you can also "ponder" the product manual-usually physical sunscreen is described as ultraviolet "protective screen", "reflector" and "light-blocking component", while chemical sunscreen is described as ultraviolet "absorber", "filter" and "filter".
Sunscreen plays a sunscreen role through inorganic and organic active ingredients, mainly to prevent sunburn, photoaging and tanning.