Water is vital for life (and for your skin health) although does not contain organic nutrients nor provide energy (it is the ultimate zero calorie drink after all). Water and SPF actives are the most powerful anti-aging ingredients and MUST HAVE in your daily skincare routine… Do you think I am joking? Well, let’s take a deep dive into water homeostasis (pun intended). Proper skin hydration improves barrier function, minimizes water loss as well as the effects of environmental stressors such as solar radiation, chemicals and pollution. Cutaneous water maintains hydrated collagen and elastin and minimizes inflammation. Why is this important? Hydrated collagen and elastin are more resistant to tensions and do not break so easily (remember damaged collagen and elastin cannot be repaired). Think about dried pasta (dried collagen) … so easy to break!... what does happen when you boil the pasta? You hydrate it and after that resists to tension much better, isn't it? Skin inflammation is an internal saboteur that creates a hostile environment promoting collagen and elastin destruction and uneven pigmentation. It must be controlled! There you have it, cutaneous water promotes barrier function, prevents extracellular matrix degradation and controls inflammation … are you convinced already? If not, let me add one last drop of information. This year, a very interesting article was published in the Journal of European Academy of Dermatology and Venereology (https://www.ncbi.nlm.nih.gov/pubmed/30835878). In this paper, they demonstrated that a moisturizer containing cholesterol, free fatty acids and ceramides (I would assume they are talking about Triple Lipid Restore 2:4:2 from SkinCeuticals) was able to increase skin hydration and epidermal function while decreasing markers of SYSTEMIC inflammation… yap! Keeping the largest organ in the human body well hydrated has some systemic benefits… and this my friends is the power of cutaneous water! Now the next question we should ask is: How we can preserve our skin hydration? Besides drinking water, I have three major heroes: Hyaluronic acid (the ultimate skin hydrator), lipids and phospholipids and Aquaporin inducers.
1. DRINK WATER: our skin gets water from either environment or from the bloodstream. When we drink the proper amount of water we hydrate from within avoiding being at the mercy of the constantly changing air humidity. Checked!
2. HYALURONIC ACID (HA or hyaluronan), the ultimate water binder and one of the most hydrophilic (water-loving) molecules in nature. HA holds 1000 times its weight in water, plumping the skin by fixing water. This super hydrator also regulates keratinocytes proliferation and differentiation, barrier formation, oxidative stress, inflammation, cell survival and wound healing. Unfortunately, we start losing HA around the age of 20 and by our 40-50s we had lost almost half of it. Restoring HA in the skin is not as simple as applying this molecule topically. HA is too big to penetrate the skin. Cosmeceuticals have used small molecular weight HA to address this issue, but this only provides stratum corneum hydration. The solution is beautiful and quiet simple: we INDUCE OUR OWN HA. Several raw materials have shown to be excellent inducers of endogenous HA. My favourites are MPC (Milk Peptide Complex from CLR. INCI name: Whey protein) and exosine-H (a marine extract from Lucas Meyer. INCI name: Water (and) butylene glycol (and) alteromonas ferment extract). MPC not only induces HA but also collagen and fibronectin, resulting in firmer and more elastic skin. Exosine-H induces filaggrin and lipid synthesis improving barrier function and preventing water loss (love multifunctional ingredients!). Green tea-derived epigallocatechin gallate (EGCG), a very powerful antioxidant, also induces HA while preventing its degradation (win-win situation).
3.LIPIDS/PHOSPHOLIPIDS: are crucial for barrier function. Cholesterol, free fatty acids and ceramides (sound familiar?) are key lipidic components of the Stratum corneum (the layer of the skin we touch everyday). Alterations in their metabolism create “holes” allowing water evaporation and penetration of pollutants and microorganisms. These “holes” are present in compromised skin, dry skin and in certain diseases such as atopic dermatitis. Using a skincare with lipids/phospholipids provides a natural and skin identical filling for those holes, which are patched immediately restoring barrier functionality. Sunflower and soy derived phospholipids, cholesterol, ceramides and free fatty acids fulfill these holes beautifully.
4. AQUAPORINS (AQP): are water channels that transport water and glycerol INSIDE THE CELLS. So, while HA fixes water and hydrates components outside our cell, AQPs hydrated our cells (hydrated cell are to grapes, like dehydrated cells are to raisins). The result is ideal, restoring extra and intracellular water balance. Skin AQPs must be induced as they are assembled inside cellular membranes. Niacinamide, glycerin, caffeine, ginseng extracts, all-trans retinoic acid, glyceryl glycosides, green tea and tea tree oil are good inducers of AQPs.
As a final remark I just want to add that we need a village to maintain skin hydrated (not an easy task) but when we know skin physiology we can optimize our decisions for successful skincare solutions.
Fun facts: 1, HA is constantly produced by skin cells reaching levels close to 0.1 or 0.5 mg/kg in the epidermis and the dermis, respectively. 2. HA’s half-life (the time it takes for the molecule to get broken down) is 3 h and less than 1 day in the epidermis and dermis, respectively. 3. AQP3 is located in the epidermis and plays a role in barrier repair and wound healing. AQP3 levels decrease with aging resulting in skin dryness. 4. Dr. Peter Agre won the 2003 Nobel Prize in Chemistry for the discovery of aquaporins, I remember this pretty clear as I was at Johns Hopkins too… big celebration! 4.INCI (International Nomenclature of Cosmetic Ingredients) names are the one which appears in the list of ingredients.
