The Untold Story of Skin Hydration
Hydration has been the buzzword in skincare for decades. The skin requires proper moisture not only for a healthy appearance, but also for age defiance. Countless articles and online posts offer tips on how to hydrate your skin. In a nutshell: 1) drink plenty of water, 2) use gentle cleansers that don’t strip the skin and 3) apply products that strengthen the skin barrier and contain water retaining ingredients. To achieve this last goal, moisturizers are filled with hyaluronic acid, aloe juice, vitamins, lipids, plant extracts, natural oils and butters. While such ingredients have certain benefits, they tend to lose their magic when the weather gets colder and the air gets drier or when you are under a lot of stress.
To find a skincare routine that will leave your skin truly hydrated, let’s take a closer look into the science of how skin retains and loses water. Our skin consists of three layers: the epidermis, dermis and hypodermis. Adjectives commonly used to describe the skin, for example radiant, resilient and hydrated, all refer to properties of the epidermis. Skin loses water through evaporation, which is largely prevented by the epidermal skin barrier. Most moisturizers address hydration concerns by preventing water evaporation, either through fortifying the epidermis to trap water inside or using additives to attract water particles in the air to the skin.
There are three types of ingredients that are commonly used in most moisturizers to help prevent water evaporation: 1) humectants, substances that attract and form chemical bonds with water molecules, such as propylene glycol, PEG, aloe, honey, hyaluronic acid, glycerin and hydrolyzed proteins; 2) emollients, including natural oil and butter, help to soften and smooth the surface of the skin; 3) occlusive agents, examples are oil with high lipids content, petrolatum, wax and silicones. These agents form a film on the skin surface and prevent water loss. They can be very effective, but can feel waxy or greasy on the skin and cause acne or folliculitis.
Let’s take a look at two examples.
First, Neutrogena Hydro Boost Water Gel
Ingredients: Water, Dimethicone (occlusive agent), Glycerin (humectant), Dimethicone/vinyl Dimenticone Crosspolymer (thickening agent), Phenoxyethaqnol (preservative), Polyacrylamide (gelling agent), Cetearyl Olivate (emulsifier), Sorbitan Olivate (emulsifier), Dimethiconol (occlusive agent), C13-14 Isoparaffin (occlusive agent), Dimethicone Crosspolymer (occlusive agent), Chlorphenesin (preservative), Carbomer (thickening agent), Laureth-7 (surfactant), Sodium Hyaluronate (humectant), Ethylhexylglycerin (preservative), Fragrance, C12-14 Pareth -12, Sodium Hydroxide, Blue 1
This popular product is loaded with petroleum-derived occlusive agents. It may have a silky, smooth feel due to dimenticone and be effective in preventing water loss in the short term, however, in the long term, it may prove counter-productive when trying to hydrate the skin and it also has the potential to worsen acne in those who are prone to clogged pores.
Second, K-beauty product Laneige Water Sleeping Mask
Ingredients: Water, Butylene Glycol (humectant), Cyclopentasiloxane (emollient), Glycerin (humectant), Cyclohexasiloxane (emollient), Trehalose (humectant), Sodium Hyaluronate (humectant), Oenothera Biennis (Evening Primrose) Root Extract, Prunus Armeniaca (Apricot) Fruit Extract, Beta-Glucan, Chenopodium Quinoa Seed Extract, Ascorbyl Glucoside, Magnesium Sulfate, Zinc Sulfate, Manganese Sulfate, Calcium Chloride, Potassium Alginate, Ammonium Acryloyldimethyltaurate / VP Copolymer, Polysorbate 20, Dimethicone (occlusive agent), Dimethiconol (occlusive agent), Dimethicone / Vinyl Dimethicone Crosspolymer, Propanediol (humectant),, Ethylhexylglycerin, Stearyl Behenate (occlusive agent), Polyglyceryl-3 Methylglucose Distearate, Hydroxypropyl Bispalmitamide MEA, Inulin Lauryl Carbamate, Alcohol, 1,2-Hexanediol (humectant), Caprylyl Glycol, Carbomer, Tromethamine, Disodium EDTA, Phenoxyethanol, Fragrance, Blue 1 (Ci 42090).
This popular product contains many more humectants and occlusive agents than the first one and may provide a better short term hydration relief. However, this product shares the same problem with the first one as all of its occlusive agents are petroleum-derived and may have adverse effect on acne-prone skin.
Now, let’s consider the other side of the equation: how the skin gets water. One unique and critical feature of the epidermis that most articles or posts fail to mention is that the epidermis does not have blood vessels. Why is this so important? Well, the epidermis relies on the dermis (a deeper skin layer) to supply nutrients, oxygen and water. Water reaches the epidermis in two ways — free diffusion from the dermis and active transportation through water channels called aquaporins on the epidermal skin cells. Theoretically, to increase the uptake of water into the skin, we can either increase the amount of water transported to the skin and/or increase the activity of these water channels.
Most of us realize that simply “drinking more” doesn’t mean more water will be transported to the skin. So it makes sense that since their discovery, these water channels have been focus of intensive research efforts by scientists and the cosmetic industry. From this research, we now know that aquaporins not only transport water, but are also responsible for transporting glycerol and urea, both of which are also important for normal skin barrier function. Scientists have also discovered that overactive water channels in the skin can lead to excess water loss and eczema. Therefore, one of the biggest questions for skin scientists at DermYoung is how to influence the skin’s water uptake to achieve optimal skin hydration from within. To do this, our scientists have devised a strategy to calm down the inflammation within the skin to prevent water channels from being over-activated while optimizing local microcirculation, allowing more blood to reach dermis. Using our proprietary blend of extracts from various plants, we are able to design a hydration plan that not only works at the surface but also within. At DermYoung, we rely on the finest natural ingredients to support healthy skin function and you will note many natural extracts in our list of product ingredients.