The Hyaluronic Acid 3 Serum
A hyaluronic acid serum for skin that still feels tight an hour after moisturizer, worn after toner and under cream. 20 ml.
No reviews yet20ml
$11.00 per 10 ml
- Korean-market formula
- Ships from California or direct from Korea
- Korean barcode and batch code intact
- Suited to
- DryDehydratedSensitiveCompromised barrier
- Helps with
- DehydrationBarrier weaknessEarly environmental damageRough surface texture
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How it works
Hydration is a layering job, and this is the water step that sits between toner and moisturizer. It goes on damp skin so the layer above it has something to hold, and the cream over the top is what keeps it there. Skin that drinks a moisturizer and still feels tight an hour later is usually short of water rather than oil, and that gap is what this step is for. It is a daily step, morning and evening, and it layers under anything else already in the routine. In the morning it goes under sunscreen, and at night under whatever cream finishes the routine.
Key benefits
- Sodium hyaluronate is fifth on the list, ahead of the amino acid blend
- COSRX's own product name states 3%; the ingredient list itself declares no percentage
- Ceramide NP, cholesterol and phytosphingosine round out a barrier-supportive base further down the list
- A small amount of lactic acid sits near the end for mild surface exfoliation, not a treatment-level dose
- Watery texture built to layer, not to replace a moisturizer
- 20 ml, a layering-serum size rather than an all-over daily pour
Inside the formula
Inside the formula
COSRX The Hyaluronic Acid 3 Serum
What is the actual sodium hyaluronate content in this Hyaluronic Acid 3 Serum?
Sodium hyaluronate sits fifth on the ingredient list, right after the water, butylene glycol, propanediol and glycerin base, though the list itself declares no percentage there, and the 3% figure comes from the product name only. Ceramide NP, cholesterol and phytosphingosine appear further down the list as a barrier-supportive trio, and a broad amino acid set rounds out the formula. This is a 20 ml bottle sized for layering rather than an all-over daily pour.
Is this serum suitable for dry, barrier-compromised skin?
Ceramide NP, cholesterol and phytosphingosine appear together on the list, the same three-lipid combination often chosen to support a weakened barrier, alongside sodium PCA and sodium lactate. Fragrance, essential oil, paraben and mineral oil are all absent from the list. That reads as a generally barrier-friendly formula, though skin under active irritation should still be patch tested before adding it to a routine.
Does the hydration from this serum last, or fade if I stop using it?
Humectants such as sodium hyaluronate hold onto water present in the skin rather than making a lasting structural change, so the plumped feeling recedes gradually if the serum is dropped from a routine. Consistent daily use keeps the amino acids and barrier lipids working alongside it. This works as an ongoing habit rather than a step that produces a permanent result on its own.
Can I use this alongside a pore-focused or retinoid product?
The formula here is built from humectants, amino acids and barrier lipids, none of which inherently conflict with a separate pore-focused or retinoid step in the same routine. A common order is toner, this serum on damp skin, then any treatment product, followed by moisturizer. Check the other product's own label for its specific layering instructions before combining the two.
How do I confirm this 20 ml bottle is the authentic Korean-market formula?
This unit's barcode, 8809598454668, is the original Korean-market code, not a substitute applied for US retail.
Not on the ingredient list below: fragrance or parfum, essential oils, parabens, sulfate surfactants, mineral oil or petrolatum and added color.
Full INCI (43): Water, Butylene Glycol, Propanediol, Glycerin, Sodium Hyaluronate, Pentylene Glycol, 1,2-Hexanediol, Diethoxyethyl Succinate, Sodium Polyacryloyldimethyl Taurate, Betaine, Xanthan Gum, Dimethicone, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Sodium PCA, Sodium Lactate, PCA, Glyceryl Acrylate/Acrylic Acid Copolymer, Hydrogenated Lecithin, Ethylhexylglycerin, Serine, Alanine, Glycine, Sodium Phytate, Sorbitan Isostearate, PVM/MA Copolymer, Glutamic Acid, Citric Acid, Lysine HCl, Threonine, Arginine, Sodium Methyl Stearoyl Taurate, Proline, Ceramide NP, Cholesterol, Caprylic/Capric Triglyceride, Phytosphingosine, Stearic Acid, Oleic Acid, Alcohol, Tocopherol, Lactic Acid, Caprylyl Glycol, Caprylhydroxamic Acid
Ingredient list read from inkeedecoder.com on 10 September 2026.
43 of 43 explained
- Water solvent
- Water is the base almost every serum, toner and cream is built on. It dissolves the water-loving ingredients and sets how light the finished texture feels. On an INCI list it is usually first, which only means it is the largest single ingredient by weight.
- Butylene Glycol humectant
- Butylene Glycol is a small glycol that does two jobs at once: it holds water in the top layer of skin and it dissolves plant extracts and actives that plain water cannot. It also thins a formula, which is why watery Korean essences lean on it.
- Propanediol humectant
- Propanediol is a plant-derived glycol used in place of propylene glycol. It hydrates, carries actives into solution, and gives a lighter, less sticky slip than glycerin at the same strength.
- Glycerin humectant
- Glycerin is the most used humectant in skincare. It draws water into the outer layer of skin and holds it there, and it is one of the very few ingredients whose hydrating effect is settled science rather than marketing. Higher amounts feel tacky, which is why it is usually blended.
- Sodium Hyaluronate humectant
- Sodium Hyaluronate is the salt of hyaluronic acid, and it is what most products labelled hyaluronic actually contain. The salt dissolves more readily and the molecule is smaller, so it sits in the outer layer of skin rather than only on top of it.
- Pentylene Glycol humectant
- Pentylene Glycol hydrates and, like the other longer-chain glycols, makes a formula less hospitable to microbes so the preservative system can be lighter. It also improves how evenly a product spreads.
- 1,2-Hexanediol humectant
- 1,2-Hexanediol is a glycol used for two reasons: it holds water like glycerin, and it makes a formula harder for microbes to live in, so less traditional preservative is needed. Korean formulas use it heavily for that second reason.
- Diethoxyethyl Succinate solvent
- Diethoxyethyl Succinate is a solvent that helps water-resistant actives spread and sink in evenly. It also leaves a light, silky feel.
- Sodium Polyacryloyldimethyl Taurate thickener
- Sodium Polyacryloyldimethyl Taurate is a polymer thickener that holds a gel stable even with a lot of salt or acid in the formula.
- Betaine humectant
- Betaine is a sugar-beet-derived humectant that cells use to hold water. In a formula it hydrates and takes the edge off cleansers and acids, which is why it often appears alongside them.
- Xanthan Gum thickener
- Xanthan Gum is a polysaccharide made by fermenting sugar. It thickens a watery formula into a gel and holds the whole thing in suspension so nothing separates. Too much of it and a serum turns stringy, which is why it appears in fractions of a percent.
- Dimethicone silicone
- Dimethicone is the most used cosmetic silicone. It forms a breathable film that smooths the surface, slows water leaving skin, and gives the slip that makes a primer or cream feel silky. It is inert and does not penetrate.
31 more explained
- Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer thickener
- This is the thickener behind most gel-cream textures. It builds a soft, bouncy gel that collapses to a light fluid as it is rubbed in.
- Sodium PCA humectant
- Sodium PCA is one of the substances skin makes for itself to hold water, part of what dermatology calls the natural moisturising factor. Added to a formula it is a strong humectant that suits skin that dehydrates quickly.
- Sodium Lactate humectant
- Sodium Lactate is the salt of lactic acid and one of the components of skin's own natural moisturising factor. At the levels used here it is a humectant and buffer rather than an exfoliant.
- PCA humectant
- PCA is pyrrolidone carboxylic acid, one of the components of the natural moisturising factor skin makes for itself. It holds water at the surface, and its salts do the same job.
- Glyceryl Acrylate/Acrylic Acid Copolymer film former
- This is a polymer that forms a moisture-holding film on the surface, usually supplied with glycerin and propylene glycol as a hydrating complex.
- Hydrogenated Lecithin emulsifier
- Hydrogenated Lecithin is lecithin with its unsaturated bonds filled in, which makes it far more stable. It emulsifies and is the standard shell for the liposomes that carry actives into the outer layer of skin.
- Ethylhexylglycerin preservative booster
- Ethylhexylglycerin softens skin and boosts a preservative system, which is why it is nearly always sitting beside phenoxyethanol or 1,2-hexanediol. It also cuts down the odour bacteria produce, so it turns up in deodorising products.
- Serine amino acid
- Serine is one of the most abundant free amino acids in the outer layer of skin, where it helps hold water. Added to a formula it is a humectant.
- Alanine amino acid
- Alanine is a free amino acid skin uses as part of its own moisture-holding system. In a formula it hydrates and conditions.
- Glycine amino acid
- Glycine is the smallest amino acid and one of the free amino acids skin holds to keep water in the outer layer. In a formula it is a humectant and a mild buffer.
- Sodium Phytate chelator
- Sodium Phytate is a rice-derived chelator used in place of EDTA. It ties up trace metals so the formula stays stable and its colour and scent hold.
- Sorbitan Isostearate emulsifier
- Sorbitan Isostearate is a mild emulsifier that holds water into oil, the direction a cleansing balm or an oil-based cream needs.
- PVM/MA Copolymer film former
- PVM/MA Copolymer is a film-forming polymer used to hold a formula in place and, in a mask, to give the peel-off film its strength.
- Glutamic Acid amino acid
- Glutamic Acid is an amino acid used as a humectant and a mild pH adjuster. It is one of the components of skin's natural moisturising factor.
- Citric Acid pH adjuster
- Citric Acid is used in tiny amounts to bring a formula to the pH its actives need, not as an exfoliant at that level. It is an AHA, so at much higher concentrations it can also exfoliate.
- Lysine HCl amino acid
- Lysine is an essential amino acid, here as its hydrochloride salt for solubility. Amino acids on a label hold water and condition the surface.
- Threonine amino acid
- Threonine is an essential amino acid used in skincare as a humectant, normally as part of an amino acid complex rather than alone.
- Arginine amino acid
- Arginine is an amino acid that does two jobs here: it holds water in the outer layer of skin, and it neutralises acidic gelling agents, which is why it often stands in for a synthetic pH adjuster.
- Sodium Methyl Stearoyl Taurate surfactant
- A taurine-based surfactant. Taurates foam well while staying mild, and they keep working in hard water where a soap does not.
- Proline amino acid
- Proline is an amino acid abundant in collagen and one of skin's own humectants. Added to a formula it holds water in the outer layer.
- Ceramide NP barrier lipid
- Ceramide NP is the most used cosmetic ceramide, the same class of lipid that makes up roughly half the mortar between cells in the outer layer of skin. Added to a cream it slots into that structure, which is why ceramide formulas feel less leaky rather than merely greasy.
- Cholesterol barrier lipid
- Cholesterol is the third of the three lipids the outer layer of skin is built from, with ceramides and fatty acids. Formulas that carry all three are following the ratio skin itself holds.
- Caprylic/Capric Triglyceride emollient
- Caprylic/Capric Triglyceride is the light fraction of coconut oil, with the heavy parts removed. It is the workhorse emollient of modern formulas: it softens skin, dissolves oil-soluble actives and absorbs without the greasy weight of a whole plant oil.
- Phytosphingosine barrier lipid
- Phytosphingosine is the backbone every ceramide is built on, and skin uses it in its own lipid layer. In a formula it works with ceramides and cholesterol and also keeps the product stable against microbes.
- Stearic Acid fatty acid
- Stearic Acid is a saturated fatty acid from plant fats, and one of the three lipid classes skin's own barrier is built from. In a formula it thickens, stabilises the emulsion and can be turned into a soap-style cleanser by adding a base.
- Oleic Acid fatty acid
- Oleic Acid is the main fatty acid in olive and many nut oils. It is a rich emollient that softens skin and can feel heavy on skin prone to congestion.
- Alcohol solvent
- Alcohol here means ethanol. It dissolves ingredients water cannot, evaporates fast so a formula sets quickly and does not feel heavy, and thins texture. In quantity it can leave dry or reactive skin feeling tight, which is why many Korean formulas avoid it and some deliberately use it for a fast, weightless finish.
- Tocopherol antioxidant
- Tocopherol is vitamin E. It is an oil-soluble antioxidant that protects the oils in a formula from going rancid and works on skin as an emollient, and it is regularly paired with vitamin C because each keeps the other going for longer.
- Lactic Acid exfoliant
- Lactic Acid is a larger AHA than glycolic, so it works nearer the surface and is easier on skin, and it is a humectant as well as an exfoliant. It is the AHA of choice for dry skin.
- Caprylyl Glycol preservative booster
- Caprylyl Glycol is a glycol that conditions skin and, more importantly, strengthens a preservative system so less of the traditional preservative is needed. It appears in most modern formulas built without parabens.
- Caprylhydroxamic Acid preservative booster
- A chelator that works by denying microbes the iron they need, which lets a formula hold at a skin-friendly pH with less conventional preservative.
- Market
- Korean market, the version sold in Korea
- EAN (barcode)
- 8809598454668
- Made in
- Republic of Korea
- Volume
- 20ml
- Category
- Serum & Ampoule / Hydrating serum
- Actives
- Ceramide NP, Lactic Acid, Sodium Hyaluronate
- Ships from
- California or Korea
Orders ship from California or direct from Korea with tracked delivery to your door, and both routes carry the same Korean-market release. Shipping is free on orders of $100 or more. Returns are accepted for 30 days, by mail.
We split shipments free, so one out-of-stock item never holds up the rest of your order.
Where this unit came from
- 1Seoul
Bought as Korean-market stock - 2Barcode
Listed against the Korean barcode on its box - 3California or Korea
Ships to you from either, as the same Korean-market release
We stock the version of a formula that is sold in Korea, not the release a brand prepares for another market under the same name. The barcode in the specification above is the Korean-market one and it is printed on the box you receive.
Every unit keeps its original barcode and batch code intact, so the unit in your hands can be checked against the brand’s own records.
Every order ships from California or direct from Korea, and returns run for 30 days.
Every claim on this page traces to the unit in the box, the barcode, the batch code and the price you can read for yourself.
How to use
- Use the Hyaluronic Acid 3 Serum after toner and before moisturizer, morning and evening, on skin still damp from the step before.
- Three or four drops covers the whole face. Press it in with flat palms instead of rubbing it around.
- Toner first, this second, then moisturizer over the top within a minute, while the layer underneath is still damp.
- Twice a day, every day. Do not leave it bare on the skin with nothing over it; a water layer with no cream on top gives most of that water back to the air.
Worth knowing
- This formula carries an active acid, so pairing it with another exfoliant in the same routine is worth spacing out.
Reviews
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COSRX The Hyaluronic Acid 3 Serum
How it felt, how your skin took it, what you layer it with. Straight answers help the next person choose.
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COSRX, Korean-market original
Hyaluronic Acid Serum, 20 ml, led by Sodium Hyaluronate.
Verify your unit when it arrives
Verify your unit when it arrives
Korean-market stock with the original barcode and batch code intact, exactly as it left Korea.
COSRX verifies units itself. Find the verification page on cosrx.com and enter the batch number and expiration date printed on your unit. Read them off the package rather than from us, which is the point.
Source: COSRX FAQ
On the unit itself
- The Korean-market barcode, unaltered from the retail package.
- The manufacturer’s batch code, exactly as the maker printed it.
정품Genuine article, Korean-market stock
What professionals say
What professionals say
What skin-care professionals say about skin care, quoted from the medical sources linked beside each.
Your skin barrier is basically your outer layer of the skin.
Melissa Piliang, MDDermatologist, Cleveland Clinic Pretty much every step of a Korean skin care routine is going to have some component of hydration.
Alok Vij, MDDermatologist, Cleveland Clinic
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