COSRX
COSRX Skin Barrier Moisturizing Cream 450ml
A copy of what your skin already makes.
Eight free amino acids, PCA and lactate in the proportions skin builds them — and 450 ml of it.
Rich, and it sinks without grease.
What this cream does
A 450 ml body and face cream that reconstructs both halves of skin's own moisture system: the natural moisturising factor inside surface cells, and the lipid mortar between them.
What NMF is, and why this list looks the way it does
Skin holds water in two places. Between the surface cells sits a lipid mortar — ceramides, cholesterol and fatty acids. Inside them sits a mixture called natural moisturising factor, and when researchers analysed it they found roughly half of it is free amino acids, with pyrrolidone carboxylic acid and lactate making up most of the rest.
Now read positions 22 to 42 of this label: Sodium PCA, Sodium Lactate, PCA, then Serine, Alanine, Glycine, Glutamic Acid, Lysine HCl, Threonine, Arginine and Proline.
That is not a shopping list. It is the measured composition of NMF, written out as an ingredient deck. Serine, glycine and alanine are the three most abundant amino acids in real NMF, and they are the three placed highest here.
And the other half, also complete
Five ceramides — NP, NS, AP, AS and EOP — with Cholesterol at 39, Stearic Acid at 24, Palmitic Acid at 43 and Phytosphingosine at 45.
Ceramides, cholesterol and free fatty acids are the three lipid classes barrier repair research treats as one system; supplying one without the others is the common shortcut. All three are here, and Ceramide EOP — the long-chain type that binds the lipid layers together rather than filling them — is included, which is usually the one dropped for cost.
A word about the petrolatum
Some people avoid it. It is worth knowing why it is here: nothing else performs as well at reducing water loss, and a barrier cream that supplies NMF and ceramides without an occlusive to hold them in place is doing half a job. Cosmetic-grade petrolatum is highly refined and does not penetrate — it sits on the surface, which is the entire point.
If it is not for you, that is a legitimate choice, and this is not your cream.
Key ingredients
Ingredient · What it is, and what it is used for
- Sodium PCA
- Salt of pyrrolidone carboxylic acid. One of the two largest non-amino-acid fractions of skin's own NMF.
- Sodium Lactate
- Salt of lactic acid. The other major NMF component; holds water and softens surface cells.
- Serine
- Amino acid. The single most abundant amino acid in human natural moisturising factor.
- Glycine
- Amino acid. Among the most abundant in NMF, and the smallest of them all.
- Petrolatum
- Semi-solid hydrocarbon mixture. The most effective occlusive known — it is what stops water leaving. Ninth on this list.
- Ceramide EOP
- Long-chain ceramide with an esterified tail. Anchors the barrier lipid layers together; usually the one left out.
- Ceramide NP
- Ceramide 3. A material skin already contains, so it reads as its own.
- Cholesterol
- Sterol. One of the three lipid classes skin's outer layer is built from — ceramides and fatty acids are the other two, and they work as a set rather than alone.
- Phytosphingosine
- Sphingoid base. The backbone that ceramides are built on, and it occurs in your own lipid layer.
- Squalane
- Saturated hydrocarbon. A material skin already contains, so it reads as its own; used to soften by filling the gaps between surface cells.
- Behentrimonium Methosulfate
- Cationic conditioning agent. Deposits on skin rather than rinsing off — it is where the slip comes from.
- Panthenol
- Provitamin B5. Used to calm irritation, and pulls water into the surface and holds it there.
How the formula works together
Three layers, and the order on the label follows them. The first nine entries build the emulsion and the seal: Cetearyl Alcohol, Caprylic/Capric Triglyceride, Cetyl Alcohol, Ceteareth-20, Behentrimonium Methosulfate, Dimethicone and Petrolatum. That is a genuinely occlusive base — this cream is built to stop water leaving, not just to add some.
Potassium Phosphate and Dipotassium Phosphate at 12 and 15 are a buffer pair, holding the pH near skin's own. That matters here: the enzymes in the outer layer only work in a narrow acidic band.
Then the NMF set, then the lipid set. Squalane, Hydrogenated Lecithin and four hyaluronates fill in around them. Tocopherol at 41 protects the oils.
Forty-nine ingredients, no fragrance and no essential oil on the list.
Who it is for
Labelled for all skin types. At 450 ml this is a body tub — arms, legs, elbows, hands — and it is one of the better-formulated ones at any size. Rich enough to use on the face at night if you are very dry, though most people will find it heavy for daytime.
How to use it
- Apply generously to dry areas — arms, legs, elbows, hands.
- Massage until absorbed, and layer again on rough patches.
- Apply to damp skin after washing; an occlusive works best over water that is already there.
- Good as an overnight treatment on very dry zones.
Details
- Size
- 450 ml
- Made in
- Korea
- NMF components
- 8 free amino acids, PCA, Sodium PCA and Sodium Lactate
- Barrier lipids
- 5 ceramides, cholesterol, two fatty acids, phytosphingosine
- Ingredients
- 49, published in full below
Full ingredient list
Aqua/Water, Glycerin, Cetearyl Alcohol, Caprylic/Capric Triglyceride, Cetyl Alcohol, Ceteareth-20, Behentrimonium Methosulfate, Dimethicone, Petrolatum, Butylene Glycol, Caprylyl Glycol, Potassium Phosphate, Ethylhexylglycerin, Disodium EDTA, Dipotassium Phosphate, Panthenol, Betaine, Synthetic Wax, Hydrogenated Lecithin, Squalane, Propanediol, Sodium PCA, Sodium Lactate, Stearic Acid, PCA, Sodium Hyaluronate, Polyglyceryl-10 Stearate, 1,2-Hexanediol, Serine, Alanine, Glycine, Hydrolyzed Hyaluronic Acid, Glutamic Acid, Lysine HCL, Threonine, Arginine, Ceramide NP, Sodium Hyaluronate Crosspolymer, Cholesterol, Hyaluronic Acid, Tocopherol, Proline, Palmitic Acid, Ceramide NS, Phytosphingosine, Sodium Acetylated Hyaluronate, Ceramide AP, Ceramide AS, Ceramide EOP
In label order, unedited.
Ships from Korea.
