The Ultimate S Serum 50ml
The Ultimate S Serum is a serum from Sulwhasoo. It suits normal, combination, dry and oily skin. Comes in a 50ml size.
No reviews yet50 ml
$1,490.00 per 100 ml
- Korean-market formula
- Ships from California or direct from Korea
- Korean barcode and batch code intact
- Suited to
- NormalCombinationDryOily
- Helps with
- A targeted treatment stepLayering under a daily moisturizer
In stock. Arrives in 3 to 7 business days
We accept
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
The Ultimate S Serum 50ml is Sulwhasoo's take on the serum step. On its own ingredient list, Dimethicone sits at position 4 of 63 on the ingredient list, a silicone that shapes a smooth, quick-setting glide rather than a heavier lotion feel. Sodium Hyaluronate sits at position 29 of 63 on the ingredient list, a salt form of hyaluronic acid that holds water at the skin's surface for a plumper feel. Beta-Glucan sits at position 33 of 63 on the ingredient list, an oat or yeast-derived polysaccharide used to support a calmer, more resilient-feeling barrier. Panax Ginseng Berry Extract sits at position 50 of 63 on the ingredient list, Korean ginseng root extract, a traditional hanbang ingredient valued in Korean formulation for its restorative reputation. Sulwhasoo is a heritage Korean luxury house built around fermented Korean red ginseng and hanbang (traditional herbal) formulation, and this formula carries that character through serum format rather than a stripped-down version of it. It belongs to the serum step, applied after toner and before moisturizer, and what it does for skin is best judged after it has had time to settle in, rather than by a single application. This is the Korean-market formula of the ultimate s serum 50ml, the version sold on shelves in Korea rather than one reworked for a different market.
Key benefits
- What it is: The Ultimate S Serum 50ml from Sulwhasoo, a Korean-market serum.
- On the ingredient list: Dimethicone, Sodium Hyaluronate, Beta-Glucan, Panax Ginseng Berry Extract, confirmed on this product's own manufacturer ingredient list rather than assumed from the category.
- Fits into the routine: belongs to the serum step, applied after toner and before moisturizer.
- Sulwhasoo is a heritage Korean luxury house built around fermented Korean red ginseng and hanbang (traditional herbal) formulation.
- Original Korean Formula: the same version sold on shelves in Korea, not a US-shelf reformulation.
Key actives
4Dimethiconea silicone that shapes a smooth, quick-setting glide rather than a heavier lotion feel
Position 4 of 63 on this product's own ingredient list, a silicone that shapes a smooth, quick-setting glide rather than a heavier lotion feel.
28Sodium Hyaluronatea salt form of hyaluronic acid that holds water at the skin's surface for a plumper feel
Position 29 of 63 on this product's own ingredient list, a salt form of hyaluronic acid that holds water at the skin's surface for a plumper feel.
32Beta-Glucanan oat or yeast-derived polysaccharide used to support a calmer, more resilient-feeling barrier
Position 33 of 63 on this product's own ingredient list, an oat or yeast-derived polysaccharide used to support a calmer, more resilient-feeling barrier.
49Panax Ginseng Berry ExtractKorean ginseng root extract, a traditional hanbang ingredient valued in Korean formulation for its restorative reputation
Position 50 of 63 on this product's own ingredient list, Korean ginseng root extract, a traditional hanbang ingredient valued in Korean formulation for its restorative reputation.
52Tocopherolvitamin E, used as an antioxidant in the formula
Position 53 of 63 on this product's own ingredient list, vitamin E, used as an antioxidant in the formula.
What is The Ultimate S Serum?
It is a serum from Sulwhasoo (50ml).
How do I use this serum?
Apply a few drops to clean skin after toner or essence and before moisturizer, morning and/or night, pressing it in rather than rubbing.
Can I use this with other serums?
Yes, layering thinnest to thickest texture is the usual rule; introduce one new serum at a time so you can tell what your skin is responding to.
Not on the ingredient list below: essential oils, parabens, sulfate surfactants, mineral oil or petrolatum and added color.
Full INCI (62): Water/Aqua/Eau, Butylene Glycol, Glycerin, Dimethicone, Alcohol Denat, Glycereth-26, Trehalose, Pentaerythrityl Tetraethylhexanoate, Polymethylsilsesquioxane, Hydrogenated Poly(C6-14 Olefin), Propanediol, 1,2-Hexanediol, Hydrogenated Lecithin, Silica, Hydrogenated Phosphatidylcholine, Bis-PEG-18 Methyl Ether Dimethyl Silane, PEG-5 Phytosterol, Dimethiconol, PEG-10 Dimethicone, Fragrance/Parfum, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Ethylhexylglycerin, Hydrolyzed Ginseng Saponins, Sodium Polyacrylate, Ammonium Acryloyldimethyltaurate/VP Copolymer, Hydrogenated Polydecene, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Sodium Hyaluronate, Xanthan Gum, Hydroxypropyl Cyclodextrin, Tromethamine, Beta-Glucan, Disodium EDTA, Methoxy PEG-114/Polyepsilon Caprolactone, Benzyl Salicylate, Sorbitan Isostearate, Polysorbate 60, Bioflavonoids, PPG-5-Laureth-5, Dextrin, Theobroma Cacao Extract, Hydrolyzed Proanthocyanidin, Honey, Limonene, Rehmannia Glutinosa Root Extract, Paeonia Lactiflora Root Extract, Lilium Candidum Bulb Extract, Polygonatum Odoratum Rhizome Extract, Panax Ginseng Berry Extract, Nelumbo Nucifera Flower Extract, Panax Ginseng Root Extract (Wild Simulated Ginseng), Tocopherol, Panax Ginseng Root Extract, Phytosphingosine, Sodium Polyaspartate, Panax Ginseng Root Protoplasts, Caprylyl Glycol, Sodium Methyl Stearoyl Taurate, Acetyl Heptapeptide-4, Acetyl Hexapeptide-8, Sodium Hydroxide, Acetyl Octapeptide-3
Ingredient list read from inkeedecoder.com on 10 September 2026.
58 of 62 explained
- Water/Aqua/Eau 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.
- 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.
- 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.
- Alcohol Denat solvent
- Alcohol Denat. is ethanol with a bitter additive that makes it undrinkable, which is a tax rule rather than a formulation choice. It behaves like alcohol: a fast-evaporating solvent that gives a weightless finish and can feel drying at higher levels.
- Glycereth-26 humectant
- Glycereth-26 is a modified glycerin that hydrates with far less stickiness than glycerin itself. It is a common way to load water into a formula that has to stay light.
- 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.
- Pentaerythrityl Tetraethylhexanoate emollient
- Pentaerythrityl Tetraethylhexanoate is a light ester emollient that gives a dry, silky finish and disperses pigment evenly.
- Polymethylsilsesquioxane silicone
- Polymethylsilsesquioxane is a silicone resin in fine sphere form. It soft-focuses the look of pores and lines and gives a smooth, powdery finish.
- Hydrogenated Poly(C6-14 Olefin) emollient
- Hydrogenated Poly(C6-14 Olefin) is a synthetic hydrocarbon emollient. It gives a smooth, silicone-like glide and is completely stable, so it does not go rancid.
- 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.
- 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.
46 more explained
- 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.
- Silica absorbent
- Silica is finely milled mineral, essentially very pure sand. It absorbs oil, stops powders clumping and soft-focuses the look of pores and fine lines.
- Hydrogenated Phosphatidylcholine emulsifier
- Hydrogenated Phosphatidylcholine is the stabilised form of the main lecithin phospholipid. It builds the liposome shells that hold an active together in a formula.
- Bis-PEG-18 Methyl Ether Dimethyl Silane silicone
- A water-soluble silicone used for a light, silky slip without an oily film. It also helps other ingredients spread evenly.
- Dimethiconol silicone
- Dimethiconol is a high-molecular-weight silicone that leaves a longer-lasting smooth film than dimethicone. It is used for lasting slip and shine.
- PEG-10 Dimethicone silicone
- PEG-10 Dimethicone is a silicone with a water-loving chain attached, so it bridges the silicone and water phases. It is used as an emulsifier and to give a light, silky feel.
- Fragrance/Parfum fragrance
- Fragrance, or Parfum, is a single declaration standing for a whole scent blend, which can be dozens of materials. Regulators allow it as a trade secret, so a list showing only this word does not say what the scent is made of. It is the most common trigger named by people with reactive skin.
- 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.
- 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.
- Hydrolyzed Ginseng Saponins plant extract
- The ginsenoside fraction of ginseng root broken into smaller pieces, usually with an enzyme acting on red ginseng. Smaller ginsenosides dissolve and spread more easily than the whole extract.
- Sodium Polyacrylate thickener
- Sodium Polyacrylate is a polymer that absorbs many times its weight in water. It thickens a formula and holds water in a gel against the skin.
- Ammonium Acryloyldimethyltaurate/VP Copolymer thickener
- This is a synthetic thickener that gels quickly and holds an emulsion stable across a wide pH range. It gives a light, non-tacky body.
- Hydrogenated Polydecene emollient
- Hydrogenated Polydecene is a synthetic hydrocarbon emollient used in place of mineral oil. It is stable, has no scent, and gives a cushioned slip without oxidising.
- 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.
- 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.
- Hydroxypropyl Cyclodextrin solvent
- Hydroxypropyl Cyclodextrin is a ring-shaped sugar that traps an active molecule inside itself, keeping it stable and releasing it slowly. It is a delivery shell rather than an active.
- Tromethamine pH adjuster
- Tromethamine neutralises acidic thickeners such as carbomer so they gel, and holds a formula near skin-friendly pH. It is used at a fraction of a percent.
- Beta-Glucan polysaccharide
- Beta-Glucan is a polysaccharide from oats or yeast. It holds a large amount of water, forms a soothing film, and is one of the ingredients formulators reach for in products aimed at reactive skin.
- 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.
- Methoxy PEG-114/Polyepsilon Caprolactone emulsifier
- A block polymer with a water-loving end and an oil-loving end. It stabilises an emulsion without a soap-type emulsifier.
- Benzyl Salicylate fragrance component
- Benzyl Salicylate is a faint floral aromatic that also holds a fragrance on skin longer. It is one of the 26 fragrance components EU labelling requires to be named.
- 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.
- Polysorbate 60 emulsifier
- Polysorbate 60 is a water-loving emulsifier used with a fatty co-emulsifier to build stable lotions and creams.
- Bioflavonoids antioxidant
- Bioflavonoids is a collective declaration for the flavonoid fraction of a plant extract, usually citrus. It names a class of plant antioxidants rather than one compound.
- Dextrin thickener
- Dextrin is a starch fragment used to thicken and to give a formula a light, powdery finish. It is also a common carrier for powdered extracts.
- Theobroma Cacao Extract plant extract
- Cocoa Extract carries polyphenols and a little caffeine. It is used as an antioxidant plant extract and gives a faint warm tint.
- Hydrolyzed Proanthocyanidin antioxidant
- Proanthocyanidins, the tannin polyphenols of grape seed and pine bark, broken into smaller water soluble fragments. The smaller pieces dissolve more readily than the whole polymer.
- Honey humectant
- Honey is a natural humectant loaded with sugars and trace acids. In a formula it holds water at the surface and leaves a soft, cushioned feel.
- Limonene fragrance component
- Limonene is the citrus-peel aromatic. It appears here because EU labelling requires 26 fragrance components to be named individually rather than hidden inside "fragrance", and it is one of them.
- Rehmannia Glutinosa Root Extract plant extract
- Chinese foxglove root, one of the standing herbal roots of Korean medicine. Its extract carries iridoid glycosides and sugars and is used as a conditioning extract.
- Paeonia Lactiflora Root Extract plant extract
- Chinese peony root, one of the oldest ingredients in East Asian herbal practice. Its extract carries paeoniflorin and is used for the look of reddened, uneven skin.
- Lilium Candidum Bulb Extract plant extract
- Madonna lily bulb extract. The bulb is starchy and mucilaginous, so the extract hydrates and is used for the look of uneven tone.
- Polygonatum Odoratum Rhizome Extract plant extract
- Solomon's seal rhizome extract, the dungulle brewed as tea in Korea. It carries mucilage and sugars, so it hydrates and leaves a soft feel.
- Panax Ginseng Berry Extract plant extract
- Extract of the ginseng fruit rather than the root. The berry carries a different balance of ginsenosides and is harvested for only a short window each year.
- Nelumbo Nucifera Flower Extract plant extract
- Lotus flower extract, from the same sacred lotus as the leaf. It carries flavonoids and sugars and is used as a conditioning, hydrating extract.
- Panax Ginseng Root Extract (Wild Simulated Ginseng) plant extract
- Ginseng Root Extract is the signature ingredient of Korean traditional skincare, carrying ginsenosides. It is used for the look of tired, dull skin, and brands often ferment it to break the ginsenosides into smaller forms.
- 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.
- 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.
- Sodium Polyaspartate chelator
- A biodegradable polymer of aspartic acid used in place of EDTA. It binds the metal ions in water that would otherwise break a formula down.
- 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.
- 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.
- Acetyl Heptapeptide-4 peptide
- A seven-amino-acid peptide with an acetyl group added for stability. It is used as a conditioning peptide for the look of firmness.
- Acetyl Hexapeptide-8 peptide
- Acetyl Hexapeptide-8 is a six-amino-acid peptide used for the look of expression lines, particularly around the eyes. It is the peptide sold under the name Argireline and is water soluble and stable.
- Sodium Hydroxide pH adjuster
- Sodium Hydroxide is a strong base used in traces to bring an acidic formula up to skin-friendly pH. None of it remains as itself once the formula is neutralised.
- Acetyl Octapeptide-3 peptide
- Acetyl Octapeptide-3 is an eight-amino-acid peptide used for the look of expression lines. It is usually paired with acetyl hexapeptide-8 rather than used alone.
- Market
- Korean market, the version sold in Korea
- Made in
- Republic of Korea
- Volume
- 50 ml
- Category
- Serum & Ampoule
- 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.
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
- 4Dimethicone
- 28Sodium Hyaluronate
- 32Beta-Glucan
- 49Panax Ginseng
Where each key active sits on the declared ingredient list, by entry number. Position is proportion: the further forward, the larger its share.
How to use
- Apply a few drops to clean skin after toner or essence and before moisturizer, morning and/or night, pressing it in rather than rubbing.
Worth knowing
- Introduce a new serum on its own for a week before adding other treatment steps.
Complete the routine
- This itemSulwhasoo The Ultimate S Serum 50ml$745.00
- Cleanse first, so the next step meets bare skinSulwhasoo Signature Ginseng Facial Soap 120g X 2ea$82.50
- The last step of the morning, over everything elseSulwhasoo MEN UV Defense Protector 50ml SPF50+ PA++++$52.50
Total for 3 items$880.00
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Sulwhasoo The Ultimate S Serum 50ml
How it felt, how your skin took it, what you layer it with. Straight answers help the next person choose.
Sulwhasoo, Korean-market original
Korean-market serum from Sulwhasoo: The Ultimate S Serum 50ml, the same formula sold on shelves in Korea.
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 the key actives in this formula, quoted from the medical sources linked beside each.
Hyaluronic acid helps bind water to collagen, which traps water in the skin. That helps make the skin more plump and full-looking.
Samantha Stein, PA-CDermatology physician assistant, Cleveland Clinic It can be especially useful for skin that is easily irritated or prone to redness, including conditions such as rosacea, eczema and contact dermatitis.
Derrick Phillips, MDConsultant dermatologist, Vogue
1 more professional perspective
Rich in antioxidants, topical ginseng can help to reduce the appearance of various signs of premature aging and repair and protect the skin.
Yunyoung Claire Chang, MDDermatologist, Yahoo Lifestyle
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