Restoring your “skin barrier” seems like a pretty hot skincare buzzword right now – and it’s actually for good reason! As much as we love our high-efficacy actives like glycolic acid and retinol, our core skincare philosophy is to always first have your skin barrier care down pat before diving into the other more glamorous skin concerns. But what even is skin barrier function and how do you take care of it? The good news is, you’re probably already doing a lot of things that are good for your skin barrier. However, given all the buzz around it, there’s bound to be a lot of new products with confusing claims. So let’s break down the entirety of skin barrier care and build a solid skincare routine strategy, chemist style.
What is “Barrier Function”?
As the name suggests, one of the most important jobs your skin has is to keep water in and keep the bad guys out (ie. pathogens, damaging UV rays, pollutants, allergens, etc.). To understand how your skin performs such an important function, we should take a closer look at skin biology.
New chemist analogy! Your skin is like a beef wellington! - It’s got some layers! The outermost layer of your skin is called the epidermis, and the outermost layer of that (the crust if you will…) is your stratum corneum (or SC). So you can think of your SC as the first line of defense against all these elements you’re exposed to daily. Incidentally, it’s also the layer of skin your skincare product interacts with, so let’s zoom in on the biology of the SC specifically.
Your entire skin is constantly turning over and shedding, which means it’s transforming all the way from the base up to the SC. When the cells make their way to the SC, they become these flattened, dead cells meant to serve and protect. The SC is mostly fatty – forming a lipid matrix with a blend of ceramides, cholesterols, and fatty acids to seal water in. The deep layers of skin are full of water, but the water exists on a gradient, slowly diminishing until you drop down to ~10% to 30% composition in the fatty SC. And there’s still more! Above the SC are lots of microbes forming our microbiome. The diversity of microbes(flora) also contributes to the general protection of our skin barrier.
So what happens when your skin barrier’s not up to par? A weakened or compromised skin barrier often shows up in the form of excessive dryness, sensitivity, irritation, and/or inflammation. Oftentimes, these symptoms also further weaken your skin barrier throwing everything off into a vicious cycle of “nope!”
*Chemist Tip: Because of this vicious cycle, we always recommend tackling skin barrier and dry skin issues first before tackling the other “more glamorous” skin concerns like anti-aging and hyperpigmentation. Why? Skin’s cellular processes all need to be functioning regularly in order to achieve the best results. It also doesn’t help that some of these actives can even further aggravate compromised skin. So let’s tackle skin stuff one step at a time.
Cleanser vs. Skin Lipids
While cleansers are not inherently designed to cause skin irritation, there is such thing as “too good of a cleanser”. Some cleanser ingredients can interact with your skin proteins and lipids, which can leave skin feeling dry, irritated, and sensitized. In fact, this is often the metric used to assess how gentle (or not) a given surfactant is. That said… it can be challenging for you to decode a cleanser as a consumer. Please check out our dedicated blog series on cleansers for more shopping tips!
Skin's Water Content
Even though your SC only contains 10% to 30% water, this water content is crucial to the SC for two main reasons: 1. Maintaining the health and regular cellular function of your skin. 2. Acting as plasticizers within SC’s corneocytes to keep these cells flexible so that they don’t become brittle and crack.
In fact, did you know that our SC can be ‘fooled’ by the environments we live in to generate a weaker, less functional SC? Seasonal changes and specific changes in humidity have been found to impair’s the SC’s water barrier function leading to more challenging structural changes in the SC.
So how do you keep your skin’s water content at a healthy level with your skincare products? Good ol’ water-grabbing humectants like glycerin, hyaluronic acid, beta-glucan, panthenol, etc. that you find in hydrating serums!
…Speaking of Cell Function, Regular Cell Turnover is so Underrated!
As far as important skin processes go, we have to mention desquamation. Desquama-who? This is the natural process where skin’s old cells regularly shed. It’s when this process slows down, that skin starts dealing with rough texture, dullness, and also contributes to dry skin. But you already know what ingredients help with this, look to your chemical exfoliants AHAs, BHAs, and PHAs. For a good refresher on tackling this concern, head to our AHA deep dive!
Stratum Corneum Lipids - Your Ceramides, Cholesterol, and Fatty Acids
Water components are only half of the puzzle, we also should take a look at your natural skin lipid content. Skin lipids are comprised of ceramides, cholesterol, and fatty acids. As we age, the amount of skin lipids you have drastically decrease, and this is also found in those with certain skin conditions such as eczema and atopic dermatitis.
It may feel like the natural instinct would be to simply replenish these fatty substances using topical creams with these components, but sadly it doesn’t appear these topical ceramides and cholesterol get incorporated into your skin’s lipid matrix just like that. But! Time and time again, studies have shown that topical lipids can help decrease TEWL over time.
*TEWL (transepidermal water loss) is one of the key measurements to determine the health of your skin barrier via the rate at which water evaporates through your skin. Though water evaporation is a natural process, an elevated TEWL often signifies a weakened stratum corneum. This is also one of the main measurements that skincare products use to make their moisturizing claims.
Shopping for “lipid-minded” skincare can definitely be a confusing field to navigate. If you look up “ceramide, cholesterol, fatty acid” skincare, you’ll soon fall into the rabbit hole that is the great ratio debate. The theory is that only a certain ratio of ceramides:cholesterol:fatty acid in products can truly help. There’s the 3:1:1 camp and then there’s the 2:4:2 side.
Our take? The specific ratio might play a role, but there’s essentially no sense in getting too granular with it. As we’ve laid out here in this article, there are clearly a LOT more complexities that the skin lipid ratio can’t address alone. Plus we can also get incredibly granular here since our skin doesn’t just contain one type of ceramides, it contains over 10 types of ceramides found in skin, with every ceramide having a different size, form, and function. And certain ratios just amongst ceramides have been studied and linked to a compromised skin barrier. We dragged you down this rabbit hole just a bit to highlight that we may never know what THE best combination of ceramides, cholesterol, and fatty acids will be since there are way more variables at play here than we can realistically test out.
But good news! There are still a few helpful chemists’ tips we can give to help you shop for a truly effective ceramide product!:
- Product format matters! We recommend creams, lotions, and balms way above toners, cleansers, and serums. Ceramides are hearty, waxy substances that naturally do best in creamy, balmy textures. Toners, cleansers, and serums that claim to have ceramides likely use ceramides at extremely low levels.
- Clinically tested complexes: Because of their waxy nature, they can be challenging to formulate at effective levels. There are ingredient suppliers that crafted clinically-tested ceramide complexes to help ease the pain of trying to work with too many different types of ceramide in formula. Fun fact! Our Mr. Reliable uses one such complex at the tested 3% level!
- Ceramide NP(Ceramide III)-Forward Products: Ceramide NP is one of the most abundant forms of ceramide naturally found in our skin. This guy also happens to have more clinical studies behind it in terms of topical efficacy and its importance for skin barrier health. (read: rare find for ceramides!)
- Unique, Clinically Tested Combinations: While the 2:4:2, 3:1:1 studies aren’t the end-all-be-all skin lipids code, these ARE products the companies dedicated significant R&D resources to testing. We’d say they’re still worth trying out!
Protect and Seal the Skin Barrier with Occlusives
Another way to decrease TEWL and seal in hydration is your good ‘ol occlusives. Occlusives are other fatty, waxy substances such as petrolatum, shea butter, beeswax, etc. that work by sealing in moisture. If your skin is on the dry side or prone to dry patches, consider adding an occlusive-heavy product to your arsenal.
And the Other Stuff!
By now, you’ve probably realized it takes a village to maintain your skin barrier. In fact, there’s even more than what we’ve listed above including anti-inflammatory ingredients, antioxidants, and niacinamide! All of these together can help reduce skin barrier irritation, maintain skin barrier’s defense against external pollutants, and further boost skin barrier health.
To sum up, you’re probably already doing a lot of the right things to take care of your skin barrier, so wanting to work on barrier care shouldn’t be something you’ll need to completely nuke your current routine for. So here’s a quick checklist of questions to ask yourself as your go through your moisturizing routine:
- Do a cleanser check-in! How does your skin feel post wash?
- Consider using an antioxidant serum in the morning.
- Do you have enough humectants in your moisturizer?
- Does your moisturizer contain occlusives, ceramides, fatty acids, and cholesterols?
- See any niacinamide in your products? Great! Remember you only need 2-5%
Di Nardo, A., Wertz, P., Giannetti, A., & Seidenari, S. (1998). Ceramide and cholesterol composition of the skin of patients with atopic dermatitis. Acta dermato-venereologica, 78, 27-30.
Proksch, E., Fölster-Holst, R., & Jensen, J. M. (2006). Skin barrier function, epidermal proliferation and differentiation in eczema. Journal of dermatological science, 43(3), 159-169.
Waller, J. M., & Maibach, H. I. (2006). Age and skin structure and function, a quantitative approach (II): protein, glycosaminoglycan, water, and lipid content and structure. Skin Research and Technology, 12(3), 145-154.
Kahraman, E., Kaykın, M., Şahin Bektay, H., & Güngör, S. (2019). Recent advances on topical application of ceramides to restore barrier function of skin. Cosmetics, 6(3), 52.
Kircik, L. H., Del Rosso, J. Q., & Aversa, D. (2011). Evaluating clinical use of a ceramide-dominant, physiologic lipid-based topical emulsion for atopic dermatitis. The Journal of clinical and aesthetic dermatology, 4(3), 34.Ishikawa, J., Narita, H., Kondo, N., Hotta, M., Takagi, Y., Masukawa, Y., ... & Hatamochi, A. (2010). Changes in the ceramide profile of atopic dermatitis patients. Journal of Investigative Dermatology, 130(10), 2511.