Green Tea Serum 80ml
Green Tea Serum is One Thing's ampoule serum (80ml), in the ONE THING, built around Camellia Sinensis Leaf Extract and Trehalose. It is used after toner and before moisturizer, as the routine's concentrated treatment step. This is the same formula Korean shoppers buy off the shelf in Seoul, not a version built for US retail.
No reviews yet80 ml
$37.50 per 100 ml
- Korean-market formula
- Ships from California or direct from Korea
- Korean barcode and batch code intact
- Suited to
- NormalCombinationDrySensitive
- Helps with
- Dehydration and a barrier that feels compromisedReactive, easily irritated skin that needs calmingThe look of fine lines and a loss of firmnessA concentrated treatment step
In stock. Arrives in 3 to 7 business days
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You’re $100.00 away from free US shipping.
- 30-day returns
- Free US shipping on orders of $100 or more
- Tracked delivery to your door
How it works
Green Tea Serum is an ampoule serum from One Thing. One Thing is a Korean single-ingredient skincare brand: each toner and serum is built from one named plant extract, with no added fragrance or color. On this jar's own ingredient list, Camellia Sinensis Leaf Extract, Trehalose, Sodium Hyaluronate, Allantoin, Adenosine are named directly, which is what the key-actives panel on this page is built from rather than from the product name alone. Camellia Sinensis Leaf Extract is green tea extract, an antioxidant-rich polyphenol source, and it is why this ampoule serum is positioned the way it is. Use it after toner and before moisturizer, as the routine's concentrated treatment step, giving it a minute to settle before the next layer goes on. One Thing sells this as the Korean-market formula, the same one stocked on shelves in Korea rather than a version built for the US market.
Key benefits
- Camellia Sinensis Leaf Extract is named directly on Green Tea Serum's own ingredient list
- Trehalose is named directly on Green Tea Serum's own ingredient list
- Sodium Hyaluronate is named directly on Green Tea Serum's own ingredient list
- Green Tea Serum fits after toner and before moisturizer, as the routine's concentrated treatment step
- One Thing's Green Tea Serum is sold here as the Korean-market formula: over-labeled in English for US sale rather than reformulated for the US market
- Green Tea Serum keeps the Korean barcode and batch code that print on the unit sold on shelves in Korea
How to use
- Apply after toner and before moisturizer. Pat or smooth it over a cleansed face and let it absorb before the next step, AM and PM.
What is Green Tea Serum?
It is One Thing's ampoule serum (80ml). Its own ingredient list names Camellia Sinensis Leaf Extract, Trehalose, Sodium Hyaluronate, Allantoin, positioned the way the key-actives panel on this page describes, rather than actives assumed from the product name. It is used after toner and before moisturizer, as the routine's concentrated treatment step.
How do I use Green Tea Serum?
Apply after toner and before moisturizer. Pat or smooth it over a cleansed face and let it absorb before the next step, AM and PM. Keep the same order every time you use it so you can tell what is actually working, and give a new step a few weeks before judging the result.
Is Green Tea Serum the authentic Korean-market formula?
Yes. This listing is One Thing's Korean-market formula: the same ingredient list, barcode and batch code as the unit sold on shelves in Korea, rather than a version reformulated for US retail. That is the whole reason to buy a Korean-market brand from a specialist rather than a general retailer.
Where does Green Tea Serum fit if I already use sunscreen or makeup?
Apply Green Tea Serum before sunscreen or makeup, and let it absorb fully first so it does not pill under the next layer. Sunscreen still goes on last in the morning, and makeup after that, regardless of how many treatment steps come before it.
Who is Green Tea Serum suited for?
It suits normal, combination, dry or dehydrated and sensitive skin, and it is not restricted to any one skin tone or age group. As with any new step, patch-test on the inner arm first if you are new to this formula or to One Thing.
Not on the ingredient list below: fragrance or parfum, denatured or SD alcohol, essential oils, silicones, parabens, sulfate surfactants, mineral oil or petrolatum and added color.
Full INCI (29): Purified Water, Diglycerin, Polyglycerin-3, Butylene Glycol, Glycerin, 1,2-Hexanediol, Saccharomyces/Rice Ferment Filtrate, Camellia Sinensis Leaf Extract, Trehalose, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Sodium Hyaluronate, Propanediol, Polyglyceryl-10 Laurate, Allantoin, Sodium Citrate, Ethylhexylglycerin, Adenosine, Citric Acid, Xanthan Gum, Glyceryl Acrylate/Acrylic Acid Copolymer, Disodium EDTA, Pvm/Ma Copolymer, Hydroxypropyltrimonium Hyaluronate, Sodium Acetylated Hyaluronate, Hydrolyzed Hyaluronic Acid, Hyaluronic Acid, Sodium Hyaluronate Crosspolymer, Hydrolyzed Sodium Hyaluronate, Potassium Hyaluronate
Ingredient list read from inkeedecoder.com on 10 September 2026.
28 of 29 explained
- Purified 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.
- Diglycerin humectant
- Diglycerin is two glycerin units joined together. It holds water like glycerin but feels less tacky, so it is used where a formula needs hydration without drag.
- Polyglycerin-3 humectant
- Polyglycerin-3 is a short chain of glycerin units used as a gentler, less sticky humectant. It also helps oils and water stay blended.
- 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.
- 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.
- 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.
- Saccharomyces/Rice Ferment Filtrate ferment
- Rice fermented with yeast and then strained, the same process behind sake and its lees. It carries amino acids and sugars and is the classic rice ferment of Korean and Japanese formulas.
- Camellia Sinensis Leaf Extract plant extract
- Camellia Sinensis is the tea plant. Green tea leaf extract carries catechins, among the most studied plant antioxidants, and is used for the look of redness and oily shine.
- Trehalose humectant
- Trehalose is a sugar that some desert plants use to survive drying out. In skincare it is a humectant that holds water in the outer layer and helps a formula feel comfortable rather than tight.
- Acrylates/C10-30 Alkyl Acrylate Crosspolymer thickener
- This is a carbomer relative with fatty side chains, so it thickens and stabilises an emulsion at the same time. It gives a light gel-cream body rather than a heavy one.
- 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.
- 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.
16 more explained
- Polyglyceryl-10 Laurate emulsifier
- Polyglyceryl-10 Laurate is a sugar-derived emulsifier and solubiliser, mild enough to be a standard choice in Korean essences. It dissolves small amounts of oil into water without any tightening feel.
- Allantoin active
- Allantoin is a comfrey-derived compound used to condition skin and soften the outer layer so it feels smoother. It is one of the standard additions to a formula built for easily irritated skin.
- Sodium Citrate pH adjuster
- Sodium Citrate is the salt of citric acid, used as a buffer: it holds a formula at a steady pH rather than pushing it in one direction. It is also a mild chelator.
- 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.
- Adenosine active
- Adenosine is a nucleoside that Korea's own cosmetic authority recognises as a wrinkle-care functional ingredient, which is why it appears on so many Korean lists at a low level. It is used for the look of fine lines and is stable and well tolerated.
- 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.
- 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.
- 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.
- Disodium EDTA chelator
- EDTA is a chelator: it locks up trace metal ions from water and packaging that would otherwise turn a formula cloudy, off-colour or rancid. It does nothing to skin and appears at a fraction of a percent.
- 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.
- Hydroxypropyltrimonium Hyaluronate humectant
- Hydroxypropyltrimonium Hyaluronate carries a positive charge, and skin carries a slight negative one, so it is attracted to the surface and stays through rinsing. It is the hyaluronic used where a formula gets washed off.
- Sodium Acetylated Hyaluronate humectant
- Sodium Acetylated Hyaluronate is hyaluronic acid modified to be part oil-loving, so it clings to skin instead of rinsing away. Formulators call it the one that stays put.
- Hydrolyzed Hyaluronic Acid humectant
- Hydrolyzed Hyaluronic Acid is hyaluronic acid cut into much shorter fragments. The smaller the fragment, the further into the outer layer it can settle, which is why serums stack several sizes together instead of using one.
- Hyaluronic Acid humectant
- Hyaluronic Acid is a sugar chain the body already makes, and one gram of it can hold several litres of water. In a formula it is a humectant that pulls water to the surface of skin and holds it in a film, which is what makes skin look plumper while it is there.
- Sodium Hyaluronate Crosspolymer humectant
- Sodium Hyaluronate Crosspolymer is hyaluronic acid linked into a mesh. It holds water in a soft gel on the surface rather than sinking in, and it releases that water slowly through the day.
- Potassium Hyaluronate humectant
- Potassium Hyaluronate is another salt of hyaluronic acid, used for the same reason as the sodium form: it dissolves easily and holds a large amount of water in the outer layer of skin.
- Market
- Korean market, the version sold in Korea
- EAN (barcode)
- 8809704190619
- Made in
- Republic of Korea
- Volume
- 80 ml
- Category
- Serum & Ampoule
- Actives
- Adenosine, Allantoin, Green Tea, Hyaluronic Acid, Sodium Hyaluronate, Trehalose
- 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.
Inside the formula
Inside the formula
Worth knowing
- New to this formula or to the brand: patch-test on the inner arm and wait a day before applying it to the face.
- Discontinue use and rinse the area with water if redness, itching or irritation develops.
Complete the routine
- This itemOne Thing Green Tea Serum 80ml$30.00
- Seal the routine in as the last stepOne Thing Cica B5 Cream 70ml$52.50
- From the same Korean-market lineOne Thing Moisturizing Lip Essence 13g$17.50
Total for 3 items$100.00
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One Thing Green Tea Serum 80ml
How it felt, how your skin took it, what you layer it with. Straight answers help the next person choose.
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One Thing, Korean-market original
Green Tea Serum, 80ml, ONE THING, One Thing's ampoule serum with Camellia Sinensis Leaf Extract and Trehalose.
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.
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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