Recently, a video went viral on the Internet. In the video, a woman asks experts in the field of skincare when the "hydration lie" will end, and says that "skin can't and doesn't need hydration". This issue has aroused widespread concern. Today, let's talk about skin hydration and hydration from a dermatologist's point of view.
Screenshot of the viral video. Swipe up and down to see
Does the skin need hydration?
Before we talk about this, we need to understand the structure of the skin.
The skin is composed of epidermis, dermis, and subcutaneous tissue. The epidermis of the skin is the part that is in direct contact with the outside world, and the stratum corneum, transparent layer, and granular layer in the epidermis are the key to maintaining moisture.
The structure of the skin丨Wikipedia
The water content of the stratum corneum is generally 15%~25%, which can not only prevent the release of water from the body, but also absorb water from the external environment.
When the skin moisture content is less than 10%, it will be difficult for the skin to metabolize normally, and its function will also be affected, the skin is like a dry earth, and the moisture, electrolytes and other substances in the skin are more easily lost through the skin. At this time, external harmful substances are also easy to invade, causing a variety of skin problems, such as skin itching, allergies, etc.
If the skin is well moisturized, the skin's cells "absorb" the water, allowing the skin to form a "protective film" again, and the skin will regain its softness and smoothness. Therefore, the skin needs to be hydrated, especially if it is dry or exposed to dry conditions.
However, what we usually call "hydration" is only the hydration of the stratum corneum, because there is the protection of the skin barrier, the moisture basically does not reach the dermis, and the skin care products that advocate the hydration of the dermis are false propaganda.
Why sometimes the more hydrated
Drier skin?
We also need to clarify the relationship between hydration and hydration. Moisturizing is mainly to prevent the loss of water from the surface of the skin, and to form a moisturizing film on the outside of it to lock in moisture, which is also called in medicine - to reduce "transepidermal water loss". For example, moisturizing is similar to putting a film on the land that contains a certain amount of water to prevent the original moisture of the land from being lost too quickly. True "hydration" is different, it is similar to watering the land in order to increase the amount of water from outside.
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Many people will find that long-term use of hydrating products, dry skin does not improve, and seems to worsen. Generally speaking, after cleansing the skin, the water content of the stratum corneum is about 30% when no skin care products are applied, and the use of skin care products can make the water content of the stratum corneum reach 70%~80% in a short period of time.
If you just use hydrating products, such as hydrating sprays, the moisture on the surface of your skin will evaporate into the air, resulting in drier skin. Therefore, if you want to "quench your thirst" for your skin in an air-conditioned room and just hydrate, you are working in the wrong direction. Use a moisturizer while hydrating to better lock in moisture and bring long-lasting hydration to your skin.
A wide range of hydrating and moisturizing products on the market
What are they?
There are many names for skin care water, including toner, astringent water, softening water, functional water, essence water, etc. They mainly have two common functions.
One is hydration. After washing your face, using skincare products can temporarily increase the water content of your skin, and after applying a topical moisturizer, the water will be trapped in the skin for long-lasting hydration, which may be better than using a moisturizer alone. Of course, if you don't use this kind of skin care water, just moisturizer to moisturize, it's not impossible.
The other is a secondary cleansing, which helps to remove residual cleansers and makeup while adjusting the pH of the skin.
In addition, in some areas, the water is hard, and washing your face with hard water for a long time can cause damage to your skin. Because the pH level of the lotion is carefully adjusted, it can be used on the surface of the skin to neutralize the pH imbalance caused by various causes and achieve the best condition of the skin. Different names of skincare products will have different effects, so you need to carefully distinguish and choose the one that suits you best.
1
Toner
It has a relatively strong function of cleaning and adjusting the pH, which is more suitable for people who often wear makeup, and it is best to dip it in a cotton pad and rub it on the face in one direction. It is best not to apply directly with your hands, as the hands themselves may not be clean enough, and the dirt that has been cleaned is still on the hands or face, which will not achieve the purpose of cleaning.
2
Astringent water
Added with ingredients to help shrink pores and control oil, it is more suitable for oily skin. It should be noted that this type of lotion may contain alcohol, so people with sensitive skin and allergies need to be careful.
3
Softening lotion
It mainly moisturizes and softens keratin, and the cleansing effect is not strong, so you can apply it directly to the face with your hands. Some products have a thicker texture that sits between water and lotion and can have some extra effects before using them in a moisturizer.
4
latex
Lotions and creams are the most mainstream and recommended moisturizers because they have a powerful moisture-locking function, and some also contain ingredients that repair the skin barrier. Among them, the biggest feature of the lotion is its high water content, which can instantly moisturize the skin and build a moisturized sebum film for the skin to prevent water loss. Compared to creams, lotions have a more refreshing texture and are more suitable for summer or normal, combination and oily skin types.
5
face cream
Creams are inherently indistinguishable from lotions, and the morphological changes of the cream are only a matter of process. In addition to the basic functions of moisturizing, some also contain other functional ingredients, such as repairing and anti-wrinkle. Night creams are usually more nourishing than day creams and will feel more oily after application. More suitable for dry autumn/winter use or dry, normal skin.
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How to choose moisturizers?
A good bottle of moisturizer is a must-have for every beauty lover. There are many types of moisturizers on the market, and the main active ingredients are divided into three types: encapsulants, moisture absorbers, and emollients.
Encapsulants can form an oily film on the surface of the skin to prevent water from evaporating, such as petroleum jelly. Hygroscopic agents are substances that absorb moisture, which can attract moisture from deep layers of the skin to the stratum corneum and can also absorb moisture from environments with high water content. Emollients are mild, lipophilic substances that make the skin softer and tougher. Different moisturizers are different ratios of these three types of substances.
So how to judge the quality of a moisturizer? There is a simple way to learn from, a well-known skin expert in China once proposed that "as long as you try this product on the face or body, the feeling of the skin is the best answer". A good moisturizer can provide a moisturized sensation for a long time, and the skin is moist, smooth and elastic after use.
Of course, when choosing any skin care products, you must remember to buy products made by regular manufacturers that meet national standards.