We polled everyone on Instagram on their top dry skin questions, and one of the most common questions we got was “just what is the difference between dehydrated and dry skin?” In a similar vein, people also wanted to know just what kind of skin deficiencies causes dry skin – lack water or oil? Understanding just what kind of dry skin you have and what your skin need can be the difference between an effective moisturizing routine and an endless loop of frustration. So in this blog post, let’s break down the skin biology of dry skin, get to the bottom of the dehydrated vs dry skin debate once and for all, and talk about the best strategies to effectively rehydrate dry skin.
Skin Barrier Biology
To understand the root cause behind your dry or dehydrated skin, we must first take a closer look at skin biology. Your skin has many layers. The outermost layer of skin is called the epidermis, and the outermost layer of the epidermis is called the stratum corneum (SC). Your SC is the layer that is in constant contact with the outside world. In other words, your SC provides the ever-important first line of defense against the elements. To do its job well, your SC primarily comprises a web of fatty ceramides, cholesterol, and fatty acids to form a water-resistant lipid matrix. This acts as a physical barrier that shields you from the elements while keeping water in. Additionally, skin secretes sebum on to the SC to keep skin lubricated while warding off infections.
Though your stratum corneum is mostly fatty, there’s a good amount of water in it as well. In fact, your SC normally should have 30% to 50% water. This water content is crucial to your skin feel, maintaining homeostasis, and signaling important skin functions like cell turnover and regulating barrier function.
So when it comes to skin hydration and barrier function, you really need both team oil and team water to work together.
Difference between Dehydrated and Dry Skin
So what is the difference between dehydrated and dry skin? This can be a matter of semantics - but generally speaking, dehydrated skin refers to skin that lacks water while dry skin refers to skin that lacks oil. But the reality is, most people experiencing dry skin needs help in both the oil and water departments. This is why, the best moisturizers are made up of a strategic blend of both water-loving ingredients and oil-loving ingredients.
So is my skin lacking water or oil?
Of course, when it comes to how to tailor your routine to solve your skin’s hydration needs, the next logical question is “how can I tell if my skin is lacking water or oil?” This can be hard to tell for sure, but typically your natural skin type gives you a clue
If your skin is naturally dry, it usually means you secrete a lot less sebum than those with normal or oily skin. This lack of oil impacts your skin’s natural ability to retain water, which means your skin is very likely also dehydrated. In your routine, this means you’d likely need to layer up starting with a hydrating serum packed with water-loving humectants (think glycerin, hyaluronic acid, lactic acid, sodium PCA, panthenol, etc.), and ending your routine on a moisturizer loaded up in occlusives such as petrolatum, butters, waxes to seal all the moisture in.
If you have oily skin, it is more likely for you to have dehydrated skin and need to replenish the water stuff. After a thorough cleanse, use a lightweight moisturizer that has water-grabbing humectants like glycerin, glycols, near the top of the ingredient list to add hydration back to your skin.
Best way to rehydrate skin
The best way to hydrate your dry skin is by using products with high levels of humectants. Humectants are ingredients with high water affinity and can draw water to the surface of skin. There are a LOT of different types of humectants you can use in your skincare. Marketing lingo may have you believe that there is “best” hydrating ingredient out there (yes, I’m looking at you, hya-lu-ron-ic acid), but hear it from the chemists! The best hydrating strategy is to use a blend of humectants in your routine.
If your skin is naturally on the dry-side, you also can’t forget the oily ingredients. A cream or balm high in petrolatum, butters, and waxes can help seal in moisture.
Sometimes, despite our best efforts in our day-to-day routine, skin can still get dehydrated. This is when sheet masks can come to the rescue! While we’d recommend not taking “brightening” “anti-aging” claims from sheet masks too seriously, what they are really good at is super soaking your stratum corneum – perfect for when your dehydrated skin needs a quick fix.
Takeaways: decoding dehydrated vs dry skin
Generally speaking, dehydrated skin refers to skin that lacks water whereas dry skin refers to those that lack oil. The reality is, if you have dry skin, it is highly likely that your skin is both dry and dehydrated. On the other hand, if you have oily skin, you might have dehydrated skin despite your skin naturally produce enough of the oil-things. Using a hydrating serum on a day-to-day basis can help fend off dehydrated skin. But sheet masks can help rescue dehydrated skin in a pinch if your skin is feeling particularly parched.
When it comes to dry and dehydrated skin, a team of the best ingredients is the key to restoring your skin barrier health!
