Doctor of Pharmacy: In addition to moisturizing, other skin care products are a waste of money! Moisturizing ingredients dry goods summary why our skin is dry? Why is moisture lost? Why moisturize (importance)? Hydration is false, moisturizing is true! How does the skin itself moisturize? What is the water-locking structure? The principle and classification of moisturizing products are analyzed and the products are listed

Man lives a face, a tree lives a skin, we can have a fucking life, but we can't have a rough face. Although the New Year is coming, the cold winter is still there. The main contradiction in the skincare industry is how to solve the problem of dry skin. Why do you frequently hydrate your skin or dry it repeatedly? Hydration, moisturizing and locking, do you really know the difference?

Hydrating and moisturizing skin care products are various, how should you choose? Hydration and moisturization are two different concepts, and only by figuring out the efficacy and principles of the ingredients can we make scientific and reasonable choices. Otherwise, there are only two eyes and one black, all relying on others to blow.

In previous articles, a detailed analysis of the main hydrating and moisturizing star ingredients, such as hyaluronic acid (hyaluronic acid), ceramides, β-dextran, alginates, panthenol (vitamin B5) and so on.

Which of these seemingly fooling ingredients is the most effective? Dr. Wang Er, a pharmacy major, tried to do a relatively comprehensive summary analysis, hoping to help the fairy girls.

Tip: The article is longer, please be patient to read, you will get something!

<h1 class="pgc-h-arrow-right" > why is our skin dry? Why is moisture lost? </h1>

As the saying goes, women are made of water, but in fact, human beings, both men and women, contain more than 70% of water.

The moisture in our skin is constantly evaporating, which is a natural process, including the spillage of water molecules in the cells, the spillage of interstitial water molecules, and the spillage of water molecules into the skin. The evaporation of moisture and the absorption of moisture are carried out at the same time, and if it is in dynamic equilibrium, it has no effect on the skin.

Once the balance is broken, the skin will have symptoms of dehydration (see the next section for specific manifestations), and there are two main factors that disrupt the balance of water in and out:

(1) Environmental factors: air dryness caused by climate and other reasons.

(2) Physical factors: insufficient secretion of sebum by the skin sebaceous glands, damage to the stratum corneum of the skin, and internal dehydration

The sebaceous membrane and stratum corneum on the surface of the skin together form a barrier to our skin, which not only prevents excessive evaporation of moisture, but also resists the invasion and irritation of harmful substances outside.

Schematic diagram of sebum structure

We may wish to compare the sebum film to a bowl of oil on the oil covered with a layer of oil, if the sebum secretion is insufficient, it is impossible to form a complete sebum film, and the water in the soup evaporates faster. If the stratum corneum is damaged, it will also open the floodgates for the evaporation of the skin's moisture.

In addition, the lack of water in the body caused by less drinking water will also make the evaporated water greater than the supplemented water, thus breaking this dynamic balance.

Skin structure

<h1 class="pgc-h-arrow-right" > Why moisturize (importance)? Hydration is false, moisturizing is true! </h1>

What symptoms does dehydration of the skin cause?

The most intuitive feeling is: the skin is hot and hot, hot and dry, uncomfortable, desquamation, rough, looks dull and dull, and even itchy, reddened and so on.

Most importantly: dehydration of the skin can lead to a weak skin barrier and hinder the normal metabolism of the stratum corneum, making the skin susceptible to infection and indirectly causing various skin problems. Dry skin can also accelerate the aging of the skin.

Why is it that hydration is nonsense, moisturizing is the right way?

60 to 70% of the water in our skin is stored in the dermis layer, and then transported from the dermis layer to the epidermis layer, but the water in the dermis layer is bound by macromolecules such as collagen and hyaluronic acid. The dermis layer can protect the water molecules in the skin from wanton loss, coupled with the strong defense system of the stratum corneum, it is also difficult for external water molecules to enter the dermis layer.

The so-called "deep hydration" in those skin care products is actually just a concept, taking hyaluronic acid as an example, the molecular weight reaches tens of thousands or hundreds of thousands, and it simply cannot pass the cuticle layer, let alone reach the dermis layer, even if the relatively small molecules of the substance, it is almost impossible to enter the dermis layer, but modern high-tech preparation technology is perhaps possible to improve this situation.

For the moisture brought by masks, sprays, etc., it is only temporary, and the large number of water molecules they contain only play a role in infiltrating the stratum corneum. Therefore, you who have just finished replenishing the water are just a watery young girl, and after the water evaporates, you return to the feeling of Ma Dajie of the neighborhood committee.

Therefore, "hydration" may be a pseudo-proposition in the skin care industry, sprays, masks can only be cool for a while, if you want to continue to moisturize, it is better to drink more water. More effective than "hydration" is "moisturizing", simulating or repairing the water-locking structure of the skin itself, that is, reducing the evaporation of water on the surface of the skin, which is the right way for skin care.

<h1 class="pgc-h-arrow-right" how does > skin moisturize itself? What is the water-locking structure? </h1>

Our skin is hydrated by a skin barrier composed of stratum corneum and sebaceous membranes.

The sebaceous glands secrete sebum and sweat, and sebum forms a sebaceous film on the surface of the skin, which isolates the invasion of bacteria to the outside and prevents the evaporation of water internally.

Healthy sebaceous film vs unhealthy sebaceous film

If the cuticles of the skin are likened to a "wall", the keratinocytes are bricks, and the intercellular lipids are mortar, which is composed of fatty acids, lipids and natural moisturizing factors (NMF). Basal cells move outward and transform into keratinocytes, which secrete sebum and natural moisturizing factors to help the skin lock in moisture during the formation of keratinocytes.

Under normal circumstances, stratum corneum (that is, old and discarded keratinocytes) falls off normally, and new keratinocytes are also forming. If the skin is dehydrated and dry for a long time, there will be fewer enzymes that control the orderly shedding of keratinocytes, and the natural shedding of keratin will be affected. In the long run, old waste horn accumulates, and the originally full and smooth stratum corneum becomes dry and brittle, thus forming a "fish scale" like markings.

<h1 class="pgc-h-arrow-right" > the principle and classification of moisturizing products</h1>

According to the principle of natural moisturizing of the skin: the water molecules are locked from the inside, and a sebum film is formed on the outside to prevent the evaporation of water. The truly effective moisturizing ingredients on the market can be divided into three categories: blocking, moisture absorption, and biomimetics.

(1) Closed

As the name suggests, a blocking agent is to build a closed structure (forming a closed film) outside the stratum corneum to isolate the contact between moisture and the outside world, thereby preventing the evaporation of moisture.

Representative ingredients: petroleum jelly, lanolin, vegetable oil, squalane, etc.

(2) Moisture absorption

The biggest feature of hygroscopic agent is hydrophilic, on the one hand, it can absorb moisture from the dermis layer to the epidermal layer, reducing the evaporation of moisture, and on the other hand, it can absorb moisture in the air (when the ambient humidity is large).

Representative ingredients: glycerin, hyaluronic acid, propylene glycol, butylene glycol, panthenol (vitamin B5), sorbitol, sodium pyrrolidone carboxylate, etc.

(3) Bionic

By mimicking the natural protective factor (NMF) of intercellular lipids in the stratum corneum, it supplements the deficiency of NMF or regulates the physiological function of the skin.

Representative ingredients: ceramide, trehalose, hyaluronic acid, allantoin, etc.

<h1 class="pgc-h-arrow-right" > ingredient analysis and product listing</h1>

(1) Blocking agent

01 Vaseline

Vaseline (vaseline), scientific name is mineral grease, is a class of polymer hydrocarbon (saturated alkane) compounds (petroleum by-products) obtained from petroleum fractions, the properties are very stable, its molecular formula is between C17H36 and C21H44, is a mixture, at room temperature is semi-solid state.

Vaseline is the closest blocker to its physiological state, reducing TEWL (Transepidermal water loss, a measure of the evaporation of water from the skin) by up to 99%. It has a certain repair effect on damaged skin.

Pros: Good results.

Disadvantages: Poor skin feeling, greasy feeling.

Advice for use: Can be used to moisturize the lips or hands, I have not bought any other lipstick since vaseline was used.

Examples of Vaseline products:

Vaseline's most classic product, not one of them (available in different specifications)

02 Squalane

Squalane is a component obtained from shark liver squalene extracted from shark liver and then hydrogenated. It can also be extracted from vegetable oils, the most abundant of which are olive oils, and can also be obtained by chemical synthesis.

Squalane structure (C30H62)

In addition to lipids and fatty acids, a major component of squalene (about 10%) is squalene, which also contains a small amount of squalane (about 2%), so squalene is a component of sebum.

However, due to the double bond in the molecular structure of squalene, the nature is unstable, which is not conducive to the preservation and use of skin care products, so in order to improve stability, more stable squalane (hydrogenation product of squalene) is used in skin care varieties. In terms of action, there is no essential difference between squalane and squalene.

Squalene structure (C30H50)

Blocking principle of squalane:

As one of the constituent components of sebum, squalane can form a sebum film on the surface of the skin, thereby acting as a blockade to prevent the evaporation of moisture and play an effective moisturizing role.

In addition, squalane can also repair the skin barrier and delay the effect of skin aging. For detailed analysis of squalane and some precautions, please refer to previous articles:

Doctor of Pharmacy: What is the use of squalane for the skin? A beauty oil that is easily forgotten

What is "hydrogenated polyisobutene"?

Hydrogenated isobutene is a synthetic component similar in structure to squalane, which is intended to mimic the efficacy of squalane, but the effect is secondary. The presence of this ingredient may be seen in some skincare products, lipsticks, lipsticks, etc.

Squalane Products List: (100% pure squalane)

The ingredient is non-irritating to the skin (even at 100% concentration), non-sensitive, safe and reliable. It inhibits mold by itself, and there is no need to add any preservatives or other ingredients to the product.

Pure squalane (domestic)

HABA Pure Squalane (2nd Generation)

(2) Moisture absorbent

03 Glycerin

Glycerine (Glycerine), also known as glycerol, the chemical formula is C3H8O3, colorless, odorless, sweet, transparent viscous liquid, with hygroscopicity, can absorb moisture from the air.

Structural formula of glycerol

Glycerol is one of the important moisturizing ingredients, belongs to the small molecule moisturizer, in the polyol moisturizer to the most prominent moisturizing effect of glycerin, in the study of moisturizing ingredients, the moisturizing effect will generally be compared with glycerol.

Glycerol this component exists from the body itself, triglycerides in the skin, decomposed into fatty acids and glycerin, the "oil" in the body is actually called fatty acid glycerides, which will also produce glycerol after being decomposed by enzymes.

In environments with high ambient humidity, glycerin has a better moisturizing effect and can absorb water molecules in the air (1 gram of glycerol can absorb 0.6 grams of water) to help the skin lock in water and maintain the skin barrier.

Precautions for using glycerin: Do not use high concentrations, let alone use pure glycerin directly, because the concentration is too high and the skin will be particularly sticky, and pure glycerin will release heat after moisture absorption.

Optimal use concentration: 10% to 20%, more than 20% of the skin will feel sticky.

Features: Glycerin should be used in an environment with high air humidity.

Because of its strong moisturizing properties, glycerin is favored in skin care products, and the moisturizing effect is first-class. It can absorb the moisture in the air to moisturize the skin, and it can also lock in the moisture in the skin and prevent it from losing it quickly.

Products containing glycerin are listed:

Glycerin No. 1 (a few dollars a bottle)

Neutrogena Neutrogena Norse Intensive Moisturizing Body Lotion 155ml

04 Polyols

Propylene glycol, butanediol and glycerol (glycerol), like glycerol, are small molecule polyol moisturizers, which can absorb moisture in the air to achieve moisturizing effects, and the effect is affected by environmental humidity. Propylene glycol and butanediol have their own characteristics, and are also used in some moisturizing skin care varieties, but the limelight is completely overshadowed by glycerin.

Features of propylene glycol:

Propylene glycol has excellent effect, long-lasting moisturizing effect, low viscosity, mild moisturizing performance, slightly special taste, odorless, viscosity is lower than glycerin viscosity, and the skin feeling is relatively refreshing. Non-irritating and non-allergenic.

1,2-Propanediol structure

Features of butanediol:

Transparent, colorless viscous liquid, with good bacteriostatic effect and excellent moisturizing properties, moisturizing with a general amount of 0.5-5%, the skin feeling is relatively refreshing, the single price is high in polyols.

1,3-Butanediol structure

sorbitol

Sorbitol, also known as sorbitol, is the main product of photosynthesis of rosaceae plants. It also belongs to the polyol moisturizer.

Sorbitol structure

peculiarity:

Hygroscopicity is less than glycerin, with a cool taste of sweetness, can improve the cold stability of the product, moisturizing effect is very gentle, generally with 75% aqueous solution, sweetness of 60% of sucrose, no irritating effect on the skin and oral mucosa, generally with mouthwash as a solvent and moisturizer.

05 Sodium pyrrolidone carboxylate

Sodium pyrrolidone carboxylate structure

Sodium pyrrolidone carboxylate (PCA-Na) is an amino acid derivative, which is a moisturizing factor naturally present in the skin, with excellent moisture absorption and a relatively refreshing skin feeling.

Features: Moisturizing performance is very significant, far more than polyol moisturizers. Ingredients are safe and available for pregnant women.

Examples of products containing PCA:

Aquamarine Mystery Rejuvenating Moisturizing Serum 30ml

albion Albion Fresh and Lustrous Penetrating Milk II (Moisturizing Type)

06 Ubiquinol (Vitamin B5)

Panthenol, also known as the precursor to vitamin B5. Vitamin B5, also known as pantothenic acid (widely present in animals and plants), is extremely unstable in nature and susceptible to temperature and formulation. Therefore, panthenol, a precursor to pantothenic acid, is used in skin care products, which is converted into pantothenic acid in the body to function.

Ubiquinol structure

Ubiquinol regulates the physiological principle of action: After panthenol is absorbed by the skin tissue, the alcohol hydroxyl group is oxidized and converted into pantothenic acid, which is the most important raw material for synthesizing coenzyme A. It has a physiological regulatory effect.

Principle of intense moisturizing:

The molecular weight of ubiquinol is small (MW=205), which can effectively penetrate the stratum corneum of the skin, moisturize the surface of the skin, and has strong hygroscopicity, and external use can increase the water content of the stratum corneum and reduce the percutaneous loss of water.

In addition to moisturizing effect, panthenol also has the effect of improving skin roughness, promoting wound healing, and protecting the hair. For a detailed analysis of ubiquinol, please refer to previous articles:

Doctor of Pharmacy: Potent and gentle repair moisturizer - panthenol (vitamin B5), composition analysis

Skincare products containing panthenol include:

(Some panthenol products will be labeled as vitamin B5 in order to appear foreign)

Shreda interprets B5 "big fat butter" with 5% high concentration ubiquinol

Surico Vitamin B5 Hydrating Serum Gel

Olay Pro-x by olay Brightening Skin Removal Serum (contains whitening ingredient niacinamide)

La Roche-posay Vitamin B5

(3) Biomimetics

07 Ceramides

Ceramide (also known as molecular nails), known as the "skincare industry's golden oil", is a naturally occurring ingredient in the skin. Intercellular lipids are the "mortar" in the "brick wall" structure that makes up the stratum corneum, and ceramides are the main components of this mortar, with a content of up to 40 to 50%.

Ceramides are chemically structured as sphingosine lipids composed of long-chain bases and fatty acids. Since different fatty acids and neurosphingosine can form different ceramides, ceramides belong to one class of molecules, not the only one. Some skin care products contain sphingomine (ceramide-like) that acts similarly to ceramides.

Ceramide structure

Moisturizing principle:

Ceramides are both hydrophilic and lipophilic, which can effectively associate water molecules and combine cholesterol, fatty acids, etc. to form a dense network structure to maintain skin moisture. When the stratum corneum is damaged or cracked, ceramides play a leading role in restoring moisture to the skin.

The difference between ceramides in healthy skin vs. dehydrated skin

Characteristics of ceramides:

In addition to moisturizing, ceramides enhance adhesion between keratinocytes (acting as "molecular nails") to reduce drying and desquamation.

In addition, ceramides also have barrier repair, anti-allergy, anti-aging and other effects in skin care. For a detailed analysis of ceramides, please refer to previous articles:

Doctor of Pharmacy: What is the use of ceramide, the ingredient of the net red ingredient? Unveil the mystery! (Collection)

Skincare products containing ceramides:

Main Yuze Skin Barrier Repair Serum

(Contains ceramide-3, (nerve) sphingolipids (ceramides), cholesterol, rich in vegetable oils, which contain fatty acids.) ）

Baby moisturizer

(Main ingredients: contains ceramides 1, 3, 6, phytosphingosine; cholesterol, a small amount of fatty acids.) Features: Affordable. ）

Home Facial Pro ceramide stock solution

(Main ingredient: Contains ceramide 3, but is free of cholesterol and fatty acids.) ）

All-round anti-wrinkle ceramide shark extract

(also contains ceramide 2, squalane)

08 Hyaluronic acid

Hyaluronic Acid (HA), also known as hyaluronic acid, belongs to the polymeric polysaccharide polymer mucopolysaccharides. The main difference between the different hyaluronic acids is the difference in molecular weight, from 50 million to 2 million daltons.

Hyaluronic acid structural unit

Natural Moisturizing Factors:

Hyaluronic acid is an indispensable ingredient in human tissues, there are collagen, hyaluronic acid and other polymers in the dermis layer of the skin, locking in 60 to 70% of the moisture in the skin, hyaluronic acid is also known as the ideal natural moisturizing factor (NMF).

Water absorption characteristics:

The hydroxyl group (-OH) in the hyaluronic acid molecule makes it have strong hydrophilicity, so it has an extremely strong water absorption and moisturizing ability, which can absorb 500 times its own weight of water. It can form a breathable film on the surface of the skin, so that the surface of the skin is moist and temporarily locks in moisture, and the larger the molecular weight, the better the hyaluronic acid film-forming.

Hyaluronic acid of different molecular weights:

Large molecule hyaluronic acid can not penetrate the skin, can only infiltrate the skin in the epidermis, but small molecule hyaluronic acid, modified hyaluronic acid (such as acetylated hyaluronic acid), and special preparations (such as nanoliposomes, etc.) hyaluronic acid, can penetrate the skin to a certain extent, rapidly hydration with cells.

Hyaluronic acid is known as the "hydrating artifact", but hydration only allows the epidermis to be temporarily infiltrated, and there are very few products that can really penetrate the stratum corneum. Hyaluronic acid forms a temporary closed film on the surface of the skin, which has a moisturizing effect, but the sealing effect of this film is not long-lasting. Therefore, a good hyaluronic acid product should have hyaluronic acid of different molecular weights, which can also partially penetrate the skin while forming a film, and should also be used with other blocking agents.

For a detailed analysis of hyaluronic acid, please refer to previous articles: Doctor of Pharmacy: Hyaluronic Acid (Hyaluronic Acid), the "Hydrating Artifact" of the Skin Care Industry, is it really useful?

Hyaluronic acid products list:

Hyaluronic acid stock solution

Muscle Research Extreme Moisturizing

Beautiful Garfen Hyaluronic Acid Stock Solution 30ml

Shirga Sodium Hyaluronate Mask

09 Trehalose

Trehalose is a natural sugar called the "sugar of life" that forms a special protective film on the surface of cells. Its chemical structure is formed by the condensation of two glucose molecules by the semi-acetal hydroxyl group, which is a non-reducing (non-reducing) sugar with stable properties.

Glucose structure (left) Trehalose structure (right)

Moisturizing mechanism:

Multiple hydroxyl groups in the trehalose structure can form hydrogen bonds with water molecules in the environment, firmly lock in water, and form a protective film with other cell matrices, thus playing a role in absorbing moisture and reducing water evaporation.

It belongs to the natural sugar class, safe and reliable, and can make desert plant cells "come back to life". In addition to moisturizing effect, it also has barrier repair, cell protection, antioxidant and other effects.

For a detailed analysis of trehalose, please refer to previous articles: Doctor of Pharmacy: Trehalose in Skin Care Products Can Bring Skin Back to Life? Where does the magic come from?

Skincare products containing trehalose are listed:

(The concentration of trehalose in skin care products is generally 1 to 5%)

Clinique Excellence Emollient

Shiseido Red Yan Muscle Vitality Serum

Tamazawa Skin Barrier Repair Moisturizer

Estée Lauder Muscle Primordial Bio-Liquid

10 β-dextran

β-glucan (Beta-Glucan) is a polysaccharide ingredient, belongs to the noble ingredient in the field of moisturizing, the efficacy can compete with hyaluronic acid, known as a dark horse in the skin care industry.

Dextran is a polysaccharide linked by glycoside bonds of the glucose unit, and only dextrans of β configuration are biologically active. β-dextran can be obtained from yeast, oats, fungi, and can now be prepared by microbial fermentation.

β-1,3 dextran, β-1,4 dextran structure

Efficient moisturizing mechanism:

β-dextran forms a film on the surface of the skin that absorbs moisture from the environment while reducing the evaporation of moisture on the surface of the skin. Not only that, but the ingredient penetrates the skin through intercellular lipids, improves the skin's condition at the cellular level, and helps the skin retain moisture from the physiological function.

Features: the moisturizing effect of β-dextran is better than that of hyaluronic acid, in addition to anti-wrinkle, promote skin regeneration, promote wound healing and other effects.

For a detailed analysis of β-dextran, please refer to previous articles: Doctor of Pharmacy: Moisturizing and Anti-Aging Rookie - β- Dextran, a dark horse in the skin care industry? parse

Skincare products containing β-dextran include:

Winona Shumin Moisturizing Special Cream

(It also contains moisturizing ingredients such as glycerin, sodium hyaluronate, β-dextran, and butylene glycol)

Winona Soothing Moisturizing Repair Serum

(It also contains squalane, glycerin, β-dextran, sodium hyaluronate, butylene glycol and other moisturizing ingredients)

Dr.G Soothing Repair Moisturizing Serum Cream

11 Allantoin

Allantoin structure

Allantoin (Alantan) acts as an emollient with a restorative, hydrophilic, absorbent and moisturizing effect that prevents moisture from dissipating.

Moisturizing principle: acts directly on keratin, increases and promotes the ability of the stratum corneum to bind water, and reduces water loss.

Features: Calms and soothes, promotes wound healing, decomposes keratin, removes dead skin, increases the water content of the skin in the process, and combats moisture loss in the dermis layer.

Skincare products containing allantoin:

SkinBetter ScienceAlphaRet® overnight cream

Derma E scar gel

Embryolisse Moisturizing Mask (contains panthenol, hyaluronic acid, allantoin and more)

Welcome to the pharmacy major @Dr. Wang Er, share dry skin care products from time to time! [Powerful]

We have consistently advocated:

Hold high the great banner of scientific skincare,

Adhere to the basic policy of not blindly following the trend,

Strive to implement the basic line of knowing the components and the mechanism of knowledge,

Achieve a great victory of not stepping on the pit, anti-routine, and easy skin care.

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