Skincare How To: Hydrate the Skin

We are, all of us, aqueous solutions. Notionally, the adult human body is 60% water, and the skin is critical to keep all of that water (and other goodness) in and all of the gunk of the world, well, out. In order to function the best to protect you, and to feel the bounciest, your skin itself needs a good water content.

Unfortunately, drinking lots of water only gets you part of the way and your skin is the last organ to benefit from it. And of course it mostly just makes you pee.

💧Ingredients for Fighting Dehydration

A lot of folks get confused about their skin being dehydrated because they diligently use moisturizer, but there’s a big difference between hydration and moisturization. Moisturization comes from oil, while hydration comes from, well, water. Moisturization is critical to help keep the water in your skin from escaping — no one wants transepidermal water loss — but it won’t necessarily fix the hydration issue.

To address dehydration, you need humectants: skincare ingredients that will help bind water into your skin. Here’s a quick-ish rundown of what to look for in an INCI list:

• Glycerin has historically been the most popular, and remains one of the most common ones because it’s inexpensive and minimally irritating. Glycol and propylene glycol (frequently seen as propanediol) are also humectants and are both derived from glycerin.
• Hyaluronic Acid (HA) has been having its moment for a while now. Hyaluronic acid is a polymer, and as such comes in at a variety of molecular weights. These different molecular weights allow it to penetrate more (or less) into your skin, which is why some brands like Hado Labo like to throw in seven. It’s naturally occurring in your body — joints, eyes and skin, of course. Some folks do get irritation from HA, and it can be detrimental if there’s not ambient water in the environment for it to bind.
• Beta Glucan is a type of polysaccharide — a word you may be familiar with as a type of prebiotic and is often found in yeast, mushrooms, algae, and grains. It has a similar molecular structure to HA, so it’s just as effective at binding water, but with less chance of irritation.
• Polyglutamic Acid is a polymer of amino acids that is a byproduct of fermentation, and can bind even more water than hyaluronic acid. In the same fermentation vein, the amino-acid rich galactomyces ferment filtrate is also considered to be a humectant.
• Peptides are often recommended for anti-aging properties, and it depends on the peptide whether those are short-term or long-term effects. But because they are short-chain amino acids, they generally function as humectants in addition to any other signalling, carrier or neurotransmitting effects.
• Lactic Acid is well known for its AHA (alpha-hydroxy acid) status, but it’s also a great humectant, even at pHs higher than it would be an effective exfoliant. Urea, like lactic acid, is often used for its keratolytic properties, but is actually a humectant found it your NMF, or natural moisturizing factors.
• Snail Mucin, also known as snail secretion filtrate, is the goop they leave behind, and, as you might expect given it’s gooey texture, has great humectant properties in addition to reparative ones. Also in the “it’s a gel and a humectant” category is aloe, specifically aloe barbadensis leaf juice and extract.

This is certainly an incomplete list — if I missed your favorite humectant, please let me know in the comments. If you want a deeper dive into the chemistry behind humectants, I recommend Lab Muffin Beauty Science’s “Skincare Chemistry: How to Pick out Humectants” blog post.

🌊 Techniques for Fighting Dehydration

Okay, so you know that you’ve got dehydrated skin, and you know what to look for in products to combat it. But what techniques do you use?

• Hydrating serums are most folks’ first stop. If I had a dollar for everyone dealing with dry skin whose first stop at addressing it was an HA serum, I could probably launch my own skincare brand. I’ve been known to poo-poo HA for sure, but a hydrating serum, especially if it’s got some skin benefits beyond just hydration, is never a bad plan. I’d recommend looking beyond hyaluronic acid, however, to some of the other ingredients I mentioned above. My first love among this category was the Benton Snail Bee Ultimate Serum. As the name might suggest, the key hydrator here is snail mucin, but the bee venom has peptide components.
• Layering toners as part of the “Seven Skins Method” is a popular choice among the k-beauty lovers among us. Because modern toners focus on hydrating the skin rather than drying it out or adjusting pH, applying multiple layers of toner builds up hydration in the skin and makes it nice and bouncy. One lovely, no-frills toner for this is the Etude House Soon Jung Ph 5.5 Relief Toner, which uses glycerin, rather than HA, for its humectant.
• Doing a damp routine rather than letting your skin dry out between steps is also very helpful — no reason to lose all that good, good hydration to the air while you’re still doing your skincare. If you find that your skin does dry out between steps, I recommend incorporating a mist. They’re pretty bougie and unnecessary otherwise, but very helpful for this. The Dear, Klairs Fundamental Ampule Mist combines a variety of plant extracts with glycerin, so it’s a beneficial product to layer up regardless.
• Finally, locking that hydration in with an occlusive is critical. Even oily skin types need moisturizer, and those with particularly bad patches of dehydration or irritation will find slugging, or applying something explicitly occlusive on top an emollient moisturizer, to be invaluable. You don’t have to go as all-in as using Vaseline, the time-honored classic for slugging — balms, sleeping masks/packs and oils, while less occlusive, may be more comfortable and just as effective for some.

Have other great skincare techniques for fighting dehydration? Let me know in the comments!