Unknowingly, spring has arrived unexpectedly. In spring, the ultraviolet ray gradually becomes stronger and the stimulation to human skin is also very strong. Therefore, friends who don't want to tan will begin to apply sunscreen for sunscreen from this time. There are two kinds of sunscreen, one is physical sunscreen and the other is chemical sunscreen. So which sunscreen is better? The editor of this article will analyze the advantages and disadvantages of physical sunscreen and chemical sunscreen, and tell you how to choose sunscreen, physical sunscreen or chemical sunscreen. What is physical sunscreen? What is chemical sunscreen?
1⃣ Understanding physical sunscreen:
Physical sunscreen is a general term for all mineral, natural or inorganic sunscreen. The biggest difference between chemical sunscreen and chemical sunscreen is that it contains two excellent ingredients: zinc oxide and titanium dioxide (you will know why it is excellent in a moment)
The function principle of physical sunscreen is: these components are like the reflective plates of physical blocks, which protect us from sunlight by reflecting sunlight.
2⃣ Know chemical sunscreen:
Chemical sunscreen is also called organic sunscreen, but the name is always confusing. People mistakenly think that chemical sunscreen is pure organic and natural, but in fact, its ingredients are some chemical ingredients, such as:
Oxybenzone oxybenzozone
Avobenzone
Octyl salicylate
Octocrylene
Trimethylcyclohexyl ester homomalate
Usually we will see several ingredients combined to work, not just a single active ingredient. The principle of chemical sunscreen is to absorb ultraviolet rays through these ingredients.
If you still don't understand the difference between them, Xiaobian will tell you the simplest way: if you can't find zinc oxide and titanium dioxide in the ingredients, you can basically judge that the product is chemical sunscreen.
What are the effects of physical sunscreen and chemical sunscreen on us?
Chemical sunscreen ingredients will be absorbed by our skin
Physical sunscreen is safer because it only stays on the surface of the skin and produces sunscreen by reflecting sunlight.
But chemical sunscreen works by absorbing ultraviolet light and converting it into heat that can be released through the skin. Studies have found that after using chemical sunscreen once, chemical components such as Oxybenzone can stay in our body for five days (think carefully and fear extremely), which can be detected in the blood and urine of breast milk.
At the same time, the report also shows that chemical sunscreen ingredients can be used as penetration enhancers to make other chemicals more easily absorbed by the body.
Of course, octinoxate cinnamate is an exception. However, because the technology is expensive to implement, we rarely see this chemical sunscreen in the market.
Chemical sunscreen can affect endocrine
One of the biggest concerns of chemical sunscreen is that it may mimic, prevent or change hormone levels (also known as endocrine interference).
Although there is no clear answer to this conclusion, the researchers found that in a variety of animal and cell studies, hydroxybenzophenone, homomalate and octinoxide all affect thyroid and reproductive hormones. A few years ago, a research report of the endocrine society proved that eight chemical sunscreen ingredients could interfere with the function of human sperm cells. Therefore, it is not easy to conclude that chemical SPF may affect our fertility.
Compared with the two main components of physical sunscreen, Mandy did not find any evidence that it would destroy hormones when collecting materials.
Chemical sunscreen can cause cell damage
Another problem with chemical sunscreen is the insufficient protection of UVA rays due to oxidative damage.
We always mentioned that free radicals are the first enemy of skin aging because they are highly reactive oxygen molecules - chemical by-products produced by exposure to environmental factors, such as smoking, pollution and (you guessed right!) ultraviolet radiation. Free radicals promote premature aging by attacking cell structure and degrading collagen and elastin fibers.
Some chemical sunscreen products have poor light stability and release these harmful by-products when they absorb UVA energy. This allows them to amplify the production of free radicals, so some chemical sunscreen ingredients may form free radicals more easily than without sunscreen.
When I saw this research, I was a little square. The study found that some SPF components can cause DNA damage in human skin cells under ultraviolet radiation. This implies potential carcinogenicity. Terrible!
But in comparison, zinc oxide, an excellent component, can provide broad-spectrum protection against UVA and UVB rays. Therefore, strong UVA filtration can inhibit the production of free radicals. For example, the following table:
Chemical sunscreen may cause skin irritation and acne
Physical sunscreen is a safer choice for acne skin and sensitive muscles. Zinc oxide and titanium dioxide have oil control effect, so they are very ideal for oil skin and mixed skin.
But at the same time, chemical sunscreen often produces various skin irritation reactions such as redness and edema.
Chemical sunscreen takes some time to take effect, and it needs to be replenished frequently
Because their working principles are different, as long as physical sunscreen is applied, it is equivalent to covering the sunscreen on the face, but chemical sunscreen absorbs heat to prevent sunscreen, so it takes about 20 minutes to work.
Some chemical sunscreen agents are not very stable. They will decompose rapidly in the sun and can't play a protective role for a long time. Therefore, it is said that sunscreen needs to be replenished for a few hours.
Physical sunscreen lasts longer, as long as you don't get wet or sweat too much. If you only sweat indoors and don't often, you hardly need to supplement it. However, if you spend a long time outdoors, it is recommended that you still need to supplement your sunscreen diligently
Physical sunscreen will have a sense of massiness, and there will be unreal white marks when applied massively
This is also one of the few but fatal shortcomings of physical sunscreen. The main components of physical sunscreen, zinc oxide and titanium dioxide, have heavy active components, which will not feel light and greasy when applied to the face. In contrast, the texture of chemical sunscreen is the touch of lightweight moisturizer.
In addition, white marks will be left on the face or body, which also makes everyone feel that this will paint a 'false face'. However, these ingredients can stay in the skin injury and will not be absorbed by us, so they are safe, but their beauty is a little poor.
However, chemical sunscreen sometimes produces white marks, which disappear after being absorbed by our skin 15 minutes later.
But the good news is that the sunscreen products with physical formula are also improving, becoming lighter and less white. Nanoparticles (small particles of zinc oxide between 1 and 100 nm), which makes the formula more transparent. Of course, nanoparticles in sunscreen will not penetrate the skin or cause damage. You don't have to worry.