Ceramides for Skin: What They Do and Why They Matter
Ceramides are the fats that hold your skin's outer layer together. Here's what they do, why levels dip, and what creams and capsules can do about it.
Key takeaways
- Ceramides are fats your skin makes. With cholesterol and fatty acids, they fill the gaps between your outer skin cells and keep water in.
- Ceramide levels can dip with age and in winter, one reason skin often feels drier in the cold months.
- Well-made ceramide creams help from the outside: in one study, a single application kept skin more hydrated for 24 hours.
- Plant ceramides taken by mouth have been studied in placebo-controlled trials, which found better skin hydration and less water loss.
If you've read a moisturizer label lately, you've probably met ceramides. They're one of the few skincare buzzwords your body actually makes itself, and they earn their place. Ceramides for skin work a bit like mortar in a brick wall: they fill the gaps between the cells of your outer layer and help keep water in. Here's what ceramides do, why levels dip, which popular claims hold up, and what the research shows for ceramide creams and for ceramides you take by mouth.
What are ceramides?
Ceramides are waxy fats, or lipids, that your skin makes. They sit in the stratum corneum, your outermost layer, where they fill the spaces between flattened skin cells together with cholesterol and free fatty acids. These lipids stack into tight, orderly layers that slow water loss and help keep unwanted substances out.1
Chemically, ceramides belong to the sphingolipids: each one is a sphingoid base joined to a fatty acid. Your skin makes many different kinds, and a 2024 review describes them as the most abundant and the most varied of the barrier's lipids.1
What do ceramides do for skin?
Picture the bricks-and-mortar structure of the skin barrier. The flattened cells are the bricks; ceramides and their partner lipids are the mortar. When that mortar is well organized, water stays in and skin feels soft and comfortable. A 2025 review lists the benefits researchers link to ceramides: building the moisture barrier, keeping skin hydrated, helping regulate the skin's pH, and supporting how skin looks and works.2
Scientists check how well the barrier holds water by measuring transepidermal water loss, or TEWL: the water that evaporates through your skin. Lower TEWL means the barrier is keeping more water in.
Why ceramide levels dip
Your ceramide supply isn't fixed. In a classic 1996 study, researchers collected lipids from the face, hands and legs of women of different ages. Ceramides and the other main barrier lipids were significantly lower in older skin.3 The study is decades old, but it fits what many people notice as the years go by. Age sits alongside the everyday things that dry skin out, from low humidity to long, hot showers, and it's worth knowing what hot water and harsh cleansers do to the barrier too.
Ceramide creams: support from the outside
Ceramides are a skincare staple for good reason. In a study by a skincare maker, a single application of a ceramide cream to healthy skin raised hydration over 24 hours and lowered water loss. At the 24-hour mark, skin hydration was higher than with three other moisturizers, while a placebo cream didn't raise it at all.4
How a cream is made matters too. Ceramides are hard to dissolve, and in a 2024 series of lab tests on disrupted skin models, a cream with ceramides, cholesterol and fatty acids in layered structures helped the barrier, but adding undissolved ceramide crystals reduced or cancelled that benefit.1 Those were lab models, not people, but they explain why good formulation makes the difference.
What you'll read online, and what the research says
Search for ceramides and you'll find the same handful of claims on skincare sites, health portals and forums. Here's how they stack up.
"Ceramides make up 50% of your skin"
You'll see figures anywhere from 30% to 50%, partly because sources count in different ways and describe different parts of the skin. The clearer picture: in the mortar of your outer layer, ceramides, cholesterol and free fatty acids are present in roughly equal numbers of molecules, about 1 to 1 to 1.1 So ceramides are one of three equal partners, which is exactly why the recipe matters.
"Most ceramide creams don't work unless they follow a 3:1:1 ratio"
This one comes from real research. In a 1996 study on mouse skin, applying just one or two of the three barrier lipids slowed repair, an equal mix allowed normal repair, and raising any one of them up to three times the others sped repair up, with similar early results in human skin.5 Later lab work showed that how ceramides are dissolved matters as much as how much is added.1 So the recipe and the formulation count. But "most creams don't work" goes too far: a well-made ceramide cream has raised hydration in people.4
"Ceramides suit every skin type"
Brands and dermatologists say this often, and it makes sense: ceramides are lipids your skin already makes, and the cream study above was done on healthy skin.4 Choose a texture you like using every day.
"Ceramides only work in skincare"
Most pages about ceramides stop at creams. But plant ceramides taken by mouth have their own placebo-controlled trials, covered below.
Ceramides and hyaluronic acid: what's the difference?
You'll often see the two on the same label, because they do different jobs. Hyaluronic acid is a humectant: it holds water, like a sponge. Ceramides help stop that water from escaping, like a lid. Together they cover both halves of the sponge and the lid, which is why they pair so well.
Can you take ceramides orally?
Yes, and this is where ceramide research gets exciting. Supplements use plant ceramides, often called phytoceramides, mostly in the form of glucosylceramides from plants such as wheat.6 Your gut breaks them down, and researchers are still mapping exactly what happens between your gut and your skin.6,7
The human trials are encouraging. A 2022 meta-analysis of 66 randomized trials in healthy adults found that ceramides taken by mouth increased skin hydration and lowered water loss compared with placebo.8 Wheat ceramides have the most research behind them:
- A 60-day trial. Sixty women aged 30 to 60 with dry skin took a wheat lipid extract, as an oil or a powder, or a placebo. With the powder, 30 mg a day, cheek hydration rose 36.8% from the start, compared with 8.2% on placebo, and water loss fell 19.0%, while it rose 3.8% on placebo. The difference already showed at day 15.9
- A 2024 trial. In 72 women with dry skin, the same wheat lipid complex improved hydration, smoothness and elasticity and lowered water loss from day 14 of the 56-day study, including in women after menopause.10
- Earlier trials of a wheat extract oil. At 350 mg a day for three months, it raised hydration on the arms and legs compared with placebo in 51 women,11 and a 12-week trial in 64 women aged 45 to 60 reported better hydration on the face and legs.12
- Beyond wheat. Ceramides from wine-making leftovers lowered water loss compared with placebo in a 12-week trial in 29 healthy adults, though hydration scores didn't differ.13
Are they safe? In the trials pooled in the 2022 meta-analysis, the supplements were safe over the study periods, which usually lasted up to 24 weeks.8 Wheat ceramide extracts come from wheat, so check the label if you avoid it. Most trials ran 8 to 12 weeks, so think of oral ceramides as a daily habit rather than a quick fix.
Why Guardenne uses Ceramosides®
When we chose a ceramide for Guardenne, we wanted one with its own placebo-controlled research, used at the dose that was studied. That's Ceramosides®, a wheat seed extract.
With 30 mg of clinically studied Ceramosides® to support skin hydration and help maintain the skin's natural moisture barrier.*
In a 60-day placebo-controlled study, skin hydration rose 36.8% in people taking 30 mg of Ceramosides®, compared with 8.2% on placebo. Guardenne uses the same 30 mg.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
The bottom line
Ceramides are one of the best-understood parts of your skin barrier: the mortar that keeps water where it belongs. Levels can dip with age and in winter, but you have good options. A well-made ceramide cream supports skin from the outside, and placebo-controlled trials show that plant ceramides taken daily can support skin hydration from within. Give it time, be consistent, and your skin's mortar has what it needs.
