Written By Mira Aguirre
Article Summary
- What are ceramides?
- Ceramide deficient skin
- How ceramides in skincare work
- Does formulation matter?
Ceramides are really having their moment in the spotlight, shooting from a little known skincare ingredient to the star ingredient of countless new launches. They’re an integral part of a healthy skin barrier but does adding them into your moisturizer actually help? Find out everything you need to know about ceramides - from what they are, how they work, and what to look for in a ceramide product.
What are Ceramides?
In order to talk about ceramides, we have to first do a quick recap of the skin barrier. The stratum corneum is the uppermost layer of our skin and what is referred to as our “skin barrier” since it serves as a protection against the outside world. And we’re talking layers of protection - from antimicrobial defenses to antioxidant systems and a photoprotective layer that helps reduce some (but not all) of the damage from the sun. The skin barrier is an intricate work of art and when it’s healthy, it performs flawlessly.
But in addition to keeping our environment out, it also keeps moisture in. The skin needs water to perform many important cellular processes and the structure of the skin barrier allows it to remain hydrated. The skin barrier is often described as a brick wall, with our skin cells as “bricks” and lipids as the “mortar” in between. The mortar needs to be in the right amount and ratio to work properly, as we will cover shortly.
Key Players in the Skin Barrier:
- Corneocytes. These are the skin cells of the skin barrier and when they reach this final layer, they’ve been flattened out and filled with keratin so they can better waterproof and protect.
- Lipid Matrix. In between the skin cells, we have a lipid matrix made up of mainly ceramides, fatty acids, and cholesterol.
- Natural Moisturizing Factor. These are the skin’s natural humectants that can be found inside the corneocytes and help keep the skin most.
- Skin Microbiome. On top of the skin surface, we have a community of microorganisms that work together with our immune system and our skin as a whole to keep it healthy.
- Cell Junctions. Anchors called corneodesmosomes bind cells together so that they remain in place and can act as our skin barrier. When it’s time for dead skin cells to shed, enzymes dissolve this “glue.”
Let’s get back to the skin lipids. I like to describe the lipids of the skin barrier like baking a cake. We need to have the right amounts of all our ingredients, otherwise the cake can end up dry or not rising enough. We also want to add everything in the right order so that we don’t get lumps and we can easily whisk all the ingredients together.
Like with baking, our skin lipids need to contain the right mixture or the skin barrier can’t work properly. They also need to be in the right arrangement. The lipids of the skin barrier are arranged into sheets called lamellae and are made up of a mix of:
50% ceramides, 25% cholesterol, and 15% fatty acids.
When we discuss the lipids and barrier function, it’s important to note we aren’t talking about sebum. We do have sebaceous glands that produce an oily substance called sebum - this is what people are referring to when they say they have oily skin. Sebum moisturizes our hair and ends up on our skin surface too but it has a different composition than the lipids in our barrier which are produced in the layer below by lamellar granules.
We have an idea of how the skin barrier is structured and how it should function. But going back to our baking analogy, what happens when we are missing important ingredients for our “skin barrier cake?”
Ceramide Deficient Skin
There are a number of things that can cause disruption to our skin barrier. Most often, this is something external like over cleansing, winter weather, or perhaps irritating acne medications. It can also be due to an underlying concern like an inflammatory skin disorder, hormones, or a medication you’re taking. Barrier disruption will reduce the ability of the skin barrier to hold onto water so the best tool to assess barrier function is something called a TEWL (trans epidermal water loss) meter, a device that measures how much water is lost from the skin.
What is really cool about our skin is that even a tiny increase in water loss sends a signal basically saying “hey, you need to repair yourself” and this initiates barrier repair. Repetitive insult to the skin barrier can become too much for the skin to repair though and that’s when we see signs of an impaired barrier. And while the skin can make fatty acids and cholesterol quickly, ceramides take longer because ceramide precursors called sphingosines must be synthesized first. Because of this, looking at the number and quantity of ceramides in the skin can help identify an impaired barrier:
- There are a number of skin disorders and other issues that correspond with ceramide deficiencies. Patients with atopic dermatitis - often referred to as eczema - have been shown to have reduced ceramide levels overall but are particularly deficient in Ceramides 1 and 3.
- Barrier disruption can also occur from external stressors like weather or over cleansing. Dry winter skin was shown to be missing Ceramide 3 and Ceramide NH.
- Research points to inflammation as the potential cause of the ceramide and fatty acid deficiencies we see in inflammatory skin disorders like acne or eczema. Meanwhile, skin lipids can also be removed from the skin with over cleansing.
So the next step is how can we help our skin when it’s not able to synthesize new ceramides quickly enough?
Ceramides in Skincare
We know that ceramides are important in our skin. But does that mean that we should add them to our skincare products?
Hyaluronic acid and collagen are found in our skin but using them topically doesn’t actually help make more of these within the skin. Instead, they’re used as humectants in skincare as they can help with skin hydration. It’s natural to wonder if this is also the case with ceramides and other barrier components like fatty acids or cholesterol.
And it's true - ceramides and fatty acids are emollients while cholesterol may be occlusive as well. This means that at minimum, they can’t hurt and should have the same benefits as any other emollient. Emollients can positively influence skin barrier function while occlusive agents trap moisture, allowing the skin to rehydrate itself. But let’s take a look at some of the research that’s been done.
Ceramide Research
- The Good. Berkers et al (2018) found that topical application of ceramides in ex vivo human skin could influence the organization of the lipid matrix, restoring the lipid arrangement of damaged skin back to a normal orthorhombic one. Other studies observed an increased concentration of ceramides after application of topical ceramides and overall, there is a lot of research showing the benefits of ceramide moisturizers.
- The Bad. Zhang et al (2011) didn’t find penetration of ceramides beyond the stratum corneum where ideally we would want to get them into the layer where ceramide synthesis occurs. While this could have been a result of a flawed study design and further research would cast further doubt on these findings, it’s important to note that not every ceramide study was favorable.
- The In-Between. There are a number of other studies that show positive results with ceramide formulations but they were not vehicle controlled. This means that the results could be due to the overall formulation rather than just the ceramides alone. There also aren’t many that measured ceramide concentration within the skin, making it hard to tell of the ceramides were beneficial due to their emollient properties or if they actually helped the skin make more of its own ceramides.
What to take away from the research so far? Essentially, ceramides show a lot of promise for improving barrier function and helping address ceramide deficiency. Further research is needed to highlight how topical ceramides work and fill some gaps in the existing research. We will dive into formulation in a second but it’s almost important to note that ceramides aren’t the only ingredient that can help restore barrier function - and a well formulated product should consider this.
Ceramides in Skincare
It’s skincare formulation where things get a little controversial where ceramides are concerned. There is a lot of debate on the ratio of not only the different ceramides, but the fatty acids and cholesterol too.
You may have heard that the “golden ratio” of 3:1:1:1 (ceramide dominant with equal amounts of cholesterol, fatty acids, and other lipids) was used in the original research and is the only ratio that will work to actually improve barrier repair.
But a deep dive into the research shows it’s not so black and white. Here are some of the considerations that this research highlights:
- Healthy vs Impaired skin. Healthy skin has a mix of 50% ceramides, 25% cholesterol, and 15% fatty acids so often ceramide products seek to mimic this. But if we are wanting to address dry winter skin or the symptoms of skin disorders, we want to specifically address what is missing.
- Ceramide Precursors. Making ceramides is like any recipe and the skin needs “ingredients” like fatty acids and sphingosine on hand. As a result, fatty acids in a formula could also help increase the ceramides in the skin.
- Study Limitations. Many of the original studies (like the multiple ones done by Mao-Quiang et al 1995-1996) on the ceramide ratios were done on mouse skin, which has a completely different lipid ratio than human skin. While research does its best to replicate real life conditions, it’s also difficult to say whether tape stripping or using acetone on human skin accurately represents skin with altered barrier function.
- Lack of Consistent Findings. Unfortunately, there’s a lot of research but there’s a lot of variability in terms of the ratios and lipids looked at and the findings of these studies. Zettersten et al (1997) found that the 3:1:1:1 ratio accelerated barrier refinery but it didn’t need to be ceramide predominant, you could use any mixture as long as you used that ratio. While other studies saw results with a single ceramide or even ceramide promoters like sphingolipids.
That’s a lot so let’s put all the puzzle pieces together. The long and short of it is that while there is significant research for ceramide moisturizers as a whole, there are gaps in the research when it comes to what ratios and concentrations to use as well as how the ceramides are actually working. Earlier research suggests that a 3:1:1:1 ratio of some kind is a good idea but this could change with further study. Ceramides also aren’t the only ingredients shown to support skin barrier health so we suggest looking for products that have both.
Ceramide Skincare Green Flags:
Final Thoughts
It’s tough when there aren’t clear answers. It would be a lot easier if I could say “here’s how ceramides work, here’s what you need to look for, and here’s the results you’ll see.” Especially when we’re talking about skincare, we just don’t always have all the research we want yet. And a big part of sharing the science responsibly is being honest when there’s things that we just don’t know.
But that doesn’t mean there aren’t some fantastic ceramide moisturizers. I love that Stratia Skin products keep barrier health at the forefront and Lipid Gold really delivers with ceramides, fatty acids, and cholesterol plus niacinamide, panthenol, and phytosphingosine. The Lipid Gold Eye Cream swaps out niacinamide for peptides and also adds occlusive agents - and I actually use this as a targeted treatment for dry areas not just the under eye.
At the end of the day, if your current moisturizer is working well and you’re seeing results then that is what matters. And debate over how ceramides work and at what ratio or concentration aside, the research indicates that they do work - as well as a skincare community that loves them!
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