Profitable myth: How skin hydration actually works
Basic Skin Care Steps "cleansing, peeling, moisturizing" many have long been brought to automatism. And although moistening has become an ordinary procedure, the process itself has not become clearer. Are we really "pouring" water into the skin? Where does this water go? And is it true that if the moisturizer does not have enough moisture in the air, it will “suck” your face dry? We understand the most exciting issues.
Text: Flu Petrova
What is moisturizing really
The phrase "moisturizer" is not so much a literal term as a marketing ploy, thought up, as they say, on Madison Avenue. The problem with the notorious moisturizing is more complicated than just "add water to the skin." Dryness can be different: dry skin is a type, a constant characteristic; dehydration is a temporary condition that can be affected. So, dry skin does not have enough oil, and dehydrated - water; how to distinguish it in practice, says, for example, the author of the blog LabMuffin Michel Wong. If it is very short, the dry skin does not shine, its pores are small, it is prone to cracking, and the concealer on it emphasizes fine wrinkles or peeling. Dehydrated skin can be oily, but the sensations remain dry and tight - dull, but at the same time manage to shine.
To understand where we are offered "add water", it is worth considering the device of the skin. The upper layer is called the epidermis, and already its upper layer is horny, it is possible to touch it with your finger in order to understand whether it is dry at all or not. Normally, in the stratum corneum of the epidermis contains natural moisturizing factors, NMF, they are water-binding components, which make up 15-20% of its weight. Among them are amino acids, lactic acid, urea, pyroglutamate sodium - and they all affect the elasticity and moisture of the stratum corneum. The development of natural moisturizing factors depends on the environment: if the body decides that it is too humid around, then the formation of filaggrin protein, from which the good half of the NMF is synthesized, is blocked. And with certain diseases like vulgar ichthyosis and psoriasis, the natural moisturizing factors in the skin may in principle be absent.
Dryness can be different: dry skin is a type, a constant characteristic; dehydration is a temporary condition that can be affected
Following the epidermis layer of the skin - the dermis. Its mesh layer, which literally supports our face, contains collagen and elastin fibers, as well as glycosaminoglycans (GAG's). Glycosaminoglycans are hyaluronic acid, chondroitin sulfates, heparin sulfate, heparin, dermatan sulfate, and other substances that bind water, attracting it from the deeper layers of the skin; then the moisture rises into the epidermis and eventually evaporates. When there is not enough water, the dermis loses volume, which means that the skin as a whole becomes less elastic.
Every day we gradually lose water. First of all, it tritely evaporates from the skin - this process is called transepidermal loss, TEWL. Such a loss is presumably increased if the barrier function of the skin is impaired or we wash ourselves too often - in the future this leads to dehydration and the very "lifeless" mind, as they like to say in advertising. In addition, the moisture level in the skin decreases with time: as the author of the Just About Skin blog explains, during aging, collagen, elastin, glycosaminoglycans, which make the skin elastic, degrade, and at the same time degrade and reproduce them. The more mature the skin, the less moist and elastic it is - therefore it does not look so smooth.
Nevertheless, we are able to influence what is happening with water in the body. First, we constantly replenish its supply with liquids that we drink and eat. Secondly, we struggle with the transepidermal loss of moisture: we humidify the air in the room (in wet conditions the water does not try to leave us suddenly), and also we use cosmetics with occlusive and water-binding components. How, by the way, the notorious two liters of water affect the skin specifically, is still clearly not clear. A regular study of three years ago, in which the subjects daily “drank up” such a volume of water during the month, showed that the deep hydration of the skin among the participants actually increased, while the transepidermal water loss did not change. The question of the benefits of such an action, nevertheless, remains open: forcibly "pouring" water into ourselves, we affect not only the skin, but the organism as a whole - and not always positive.
How do "moisturizing" ingredients
The word “moisturizing” on the label most often hides three different types of substances (there are also substances involved in the renewal of skin proteins, but their direct role in moisturizing is questionable). Water-binding components attract water and keep it in the skin. Occlusal - reduce moisture loss. Softening - fill the gaps between the scales, smoothing the texture of the skin, and at the same time improving its barrier function; the latter include lipids, oils, fatty alcohols. Only the first two types of ingredients are directly related to water: one keeps it, and the other works like a locked door and prevents moisture from escaping.
Occlusive substances are literally called “blocking”: they create a film on the skin that reduces transepidermal fluid loss. These include petrolatum, lanolin acid, mineral oil, cholesterol, beeswax, squalene. Some substances, such as cyclomethicone and dimethicone, are in addition softening, which is logical from the point of view of the mechanics of the process: filling the space between the scales, the substance at the same time creates a protective layer. Means with occlusive components should be applied to moist skin, so that they have something to “lock up”: it is recommended to distribute the cream between the palms and apply in the direction of growth of hair follicles.
Water-binding components attract water and keep it in the skin. Occlusive - reduces moisture loss. Softening - fill the gaps between skin scales
Water-binding components in cosmetics are synthesized NMF and GAG's, or substances that are close to them in their properties. The horror story about a vampire cream, mercilessly sucking all the water out of your face, did not appear from scratch: water-binding components can actually increase transepidermal water loss by pulling water out of the deep layers of the skin, so they are often combined with occlusive substances. In cosmetic compositions, water binding elements may be called differently. So, hyaluronic acid is, as noted by the authors of The BeautyBrains blog, and "hyaluronic acid", and "sodium hyaluronate", and "hyaluronan", and "sodium acetyl hyaluronate", and "hydrolyzed hyaluronic acid". And in the international nomenclature of cosmetic ingredients (INCI), it is generally called "sodium hyaluronic acid".
We have already talked about hyaluronic acid and its application in cosmetology. In short, it is impossible to take it inside - or rather, it is possible, but only the joints will receive their share of benefit. But this substance can be injected under the skin - for example, hyaluronic acid contains fillers for facial contour correction. To do this, a biodegradable gel is injected into the dermis to compensate for the lack of volume and elasticity where the wrinkle is laid, or to change the outlines of the cheekbones, lips or nose. In addition, on the basis of hyaluronic acid, biorevitalizants are made for the corresponding procedure, which are slightly injected along the entire perimeter of the face. As a result, moisturizing is at its maximum: the procedure helps to correct very fine wrinkles, dull complexion, hands or décolleté, minimize the signs of photo-aging, and smooth out skin relief in general. True, hyaluronic acid injectable formulations dissolve relatively quickly.
Do I need to "moisturize"?
So you need to constantly "moisturize" the skin or not? The answer is boring: according to the situation. The decisive role here is played by the individual skin condition of a single person. Dry skin can be actively “moisturized” throughout life: due to the low amount of lipids and NMF, its skin barrier is permanently damaged, and the transepidermal water loss is accelerated - and therefore occlusive means and softening components will help it to look more elastic. Dehydrated, however, until it ceases to be so, after which it will be possible to return to the minimum daily care; here, among others, water-binding components come in handy to keep more water.
Sufficient moisturizing for normal skin is cosmetics with water-binding and occlusive ingredients that will resist natural transepidermal moisture loss. However, moisturizing oily skin and skin with acne should be moderate - in this case it is worth checking the composition of the cream for comedogenicity. Simply put, this kind of money is needed if it’s more comfortable with them than without them. True, here we must not overdo it: studies show that assiduously applying moisturizer on normal skin (three times a day for a month) can make it more sensitive to stimuli.
At the same time, “moistening” is an intelligible, and therefore, a profitable idea, therefore, among the corresponding products there are their own fashion trends. So, in the famous Hada Labo Gokujyun lotion (in the dry skin version) there are three options for hyaluronic acid: “sodium hyaluronate”, “hydrolized hyaluronic acid sodium” and “sodium acetylated hyaluronate” - and these substances are closer to the end of the composition, which means , their content is not so great. And in the second and third places in the product "butylene glycol", and "glycerin" are also water-binding components, but never hyaluronic acid is just "lotion with butylene glycol and also with glycerin" does not sound so beautiful. The classic “moisturizing” cream Nivea in a blue jar, according to the list of ingredients, is rather “moisture blocking” cream Nivea. A 72-hour intensive moisturizing Clinique gel promises including an “instant increase in humidity” thanks to a technology that “helps the skin maintain moisturizing at a constant level” - that is, it locks the water. Translated into the language of cosmetic chemistry, marketing promises no longer look like a breakthrough. All that remains is to focus on the individual needs of the skin, and also gain strength and wait to find out what will be considered “moisturizing” in twenty years.
Photo: Vladimir - stock.adobe.com (1, 2, 3)