1st on the list, which puts it at an estimated 30–80% of the formula.
Aqua (EU),Deionized Water,Distilled Water,Micromatrix Fractile AN,Onsen-Sui (JPN),Purified Water
COSRX
The Vitamin C 23 serum
face serum
COSRX
face serum
Added Last edited
Fit by skin type
General, ingredient-based — not your personalized match.
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Take the skin testThe COSRX Vitamin C 23 serum is a highly concentrated serum that contains 23% pure vitamin C, also known as L-ascorbic acid. Vitamin C is a powerful antioxidant that helps to protect the skin from environmental stressors and free radicals, while also brightening and evening out the skin tone. In addition to vitamin C, this serum also contains hyaluronic acid, tocotrienol, and allantoin. Which work together to soothe, promote collagen production, and hydrate the skin. This lightweight formula of the Vitamin C 23 serum makes it suitable for all skin types, including sensitive skin.
The Vitamin C 23 serum is a lightweight serum from COSRX, a brand based in Korea. The formula is built mainly around hydration. The ingredient list runs to 34 ingredients, each broken down in full below.
By its ingredient list the formula reads as light: water and humectants lead, with emollients kept lower in the order. It contains both silicones and oils, a combination that usually finishes smooth and slightly satin and sits well under makeup. Hydration is handled by Propanediol, Panthenol and Sodium Hyaluronate, humectants that pull water into the upper layers of skin rather than sealing it there.
Hydration: High. Ingredients that pull and hold water in the upper layers of skin, and here that comes from Propanediol, Panthenol, Sodium Hyaluronate and Butylene Glycol.
Brightening: Moderate. Ingredients that act on uneven tone and post-inflammatory marks, and here that comes from Ascorbic Acid, Niacinamide, Glycyrrhiza Glabra Root Extract and Acetyl Glucosamine.
Soothing: Moderate. Ingredients aimed at visible redness and reactivity, and here that comes from Panthenol, Allantoin, Sodium Hyaluronate and Adenosine.
Antioxidant support: Moderate. Ingredients that mop up free radicals from UV and pollution, and here that comes from Ascorbic Acid, Glutathione and Tocopherol.
On richness alone it suits Balanced skin best, and is the least natural fit for Dry and Combination (dry) skin. Nothing in the list is flagged as a common irritant, which is a reasonable starting point for reactive skin — though a patch test is still the only way to know.
The formula contributes little or nothing on cell renewal and firmness signalling. That is not a fault — most products are not meant to do everything — but if one of those is your priority, this is not the product that will address it.
Reading the full list, the formula is fragrance-free, essential-oil-free, paraben-free, microplastic-free, sulfate-free and dye-free. Those claims come from the ingredient list itself, not from the packaging. It does contain drying alcohol, worth knowing if your skin reacts to any of them.
It can be used morning and evening. In a routine it goes after toner, before moisturiser. Apply to clean, dry skin and give it a minute to absorb before the next layer. Introduce one new treatment at a time so you can identify what is working.
This summary is generated from the product's ingredient list. It is not a review, it is not the brand's own marketing claims, and it does not replace advice from a dermatologist.
Drawn purely from the ingredient list
Scored on how rich or light the formula reads from its INCI order.
No ingredient in this formula carries a common-irritant flag, making it a reasonable option for reactive skin. A patch test is still recommended, as individual skin reactivity varies.
Based on the curated benefits documented for this product's ingredients.
Attracts and locks in moisture to keep skin plump and dewy
Boosts collagen and cell turnover to reduce fine lines and wrinkles
Calms redness, irritation, and inflammation for sensitive skin
Brightens and balances complexion for a more uniform appearance
Fades hyperpigmentation and evens out dark spots over time
Regulates sebum production to reduce shine and greasiness
Tightens and refines the look of enlarged pores
None of the ingredients in this formula are associated with these benefits. This is not unusual, as most products are designed to target a limited number of concerns.
The actives, UV filters and benefit-carrying ingredients in this formula, in the order they are listed.
1st on the list, which puts it at an estimated 30–80% of the formula.
Aqua (EU),Deionized Water,Distilled Water,Micromatrix Fractile AN,Onsen-Sui (JPN),Purified Water
2nd on the list, which puts it at an estimated 5–20% of the formula.
Ascorbic acid
3rd on the list, which puts it at an estimated 5–20% of the formula.
1,3-dihydroxypropane
4th on the list, which puts it at an estimated 2–10% of the formula.
Dimethicone
6th on the list, which puts it at an estimated 2–10% of the formula.
Butanamide, 2,4-dihydroxy-N-(3-hydroxypropyl)-3,3-dimethyl-, (2R)-; dl-Panthenol
8th on the list, which puts it at an estimated 1–5% of the formula.
2,6,10,15,19,23-Hexamethyltetracosane
9th on the list, which puts it at an estimated 1–5% of the formula.
1H-Purine-2,6-dione, 3,7-dihydro-1,3,7-trimethyl-
11th on the list, which puts it at an estimated 1–3% of the formula.
Hyaluronic acid, sodium, salt
14th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Glycine, N-(N-L-.gamma.-glutamyl-L-cysteinyl)-
15th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
6-Amino-9-beta-D-ribofuranosyl-9H-purine
16th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
N-acetyl-.alpha.-D-glucosamine
18th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Urea, (2,5-dioxo-4-imidazolidinyl)-
Each axis is scored from the ingredients present and how high up the list they sit.
Ingredients that pull and hold water in the upper layers of skin
Lipids and repair signals that support skin barrier integrity
Ingredients that mop up free radicals from UV and pollution
Ingredients that moderate sebum or absorb shine
Ingredients that act on uneven tone and post-inflammatory marks
Ingredients aimed at visible redness and reactivity
Retinoids, acids and enzymes that speed surface turnover
Peptides and growth factors that signal for collagen support
"Active" here means an ingredient carrying a recorded active type or a recognised UV filter.
Solvents, emollients, texture agents and preservatives — the formula that carries the actives.
Read from the full ingredient list. A brand's own claim may differ.
Alcohol Denat.
Dimethicone, Methyl Trimethicone
Helianthus Annuus Seed Oil, Carthamus Tinctorius Seed Oil, Camellia Japonica Seed Oil
Judged by the same curated rules our routine checker uses. It reads the ingredients, not the label.
Best kept to separate routines — one in the morning, one at night, or on alternate days.
Can be layered, but the combination raises the irritation risk. Go slowly.
Can be layered, but the combination raises the irritation risk. Go slowly.
Can be layered, but the combination raises the irritation risk. Go slowly.
This product is the "Treat" step.
Flags to check, not verdicts. None of this is medical advice — if you are pregnant, breastfeeding or treating a skin condition, ask a doctor.
Most ingredients do more than one job, so these counts add up to more than the 34 ingredients on the label.
Dissolves and carries everything else
Softens and smooths by filling gaps between skin cells
Sets the thickness, spread and stability of the formula
Changes how skin behaves rather than how it feels
Neutralises free radicals from UV and pollution
Botanical material, usually for antioxidants or scent
Calms visible redness and irritation
Draws water into the upper layers of skin
Forms a film that slows water loss
Sets the acidity the formula needs to work
Keeps the product free of microbial growth
Binds trace metals that would otherwise spoil the formula
Absorbs or scatters ultraviolet light
Every ingredient on the label, in order, with what it does and roughly how much of it is likely to be there.
1st on the list, which puts it at an estimated 30–80% of the formula.
Aqua (EU),Deionized Water,Distilled Water,Micromatrix Fractile AN,Onsen-Sui (JPN),Purified Water
2nd on the list, which puts it at an estimated 5–20% of the formula.
Ascorbic acid
3rd on the list, which puts it at an estimated 5–20% of the formula.
1,3-dihydroxypropane
4th on the list, which puts it at an estimated 2–10% of the formula.
Dimethicone
5th on the list, which puts it at an estimated 2–10% of the formula.
1,3-Propanediol, 2-amino-2-(hydroxymethyl)-
6th on the list, which puts it at an estimated 2–10% of the formula.
Butanamide, 2,4-dihydroxy-N-(3-hydroxypropyl)-3,3-dimethyl-, (2R)-; dl-Panthenol
7th on the list, which puts it at an estimated 1–5% of the formula.
Ethane, 1,1'-oxybis
8th on the list, which puts it at an estimated 1–5% of the formula.
2,6,10,15,19,23-Hexamethyltetracosane
9th on the list, which puts it at an estimated 1–5% of the formula.
1H-Purine-2,6-dione, 3,7-dihydro-1,3,7-trimethyl-
10th on the list, which puts it at an estimated 1–5% of the formula.
Sodium chloride
11th on the list, which puts it at an estimated 1–3% of the formula.
Hyaluronic acid, sodium, salt
12th on the list, which puts it at an estimated 1–3% of the formula.
Sodium sulphite
13th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Disodium dihydrogen ethylenediaminetetraacetate
14th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Glycine, N-(N-L-.gamma.-glutamyl-L-cysteinyl)-
15th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
6-Amino-9-beta-D-ribofuranosyl-9H-purine
16th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
N-acetyl-.alpha.-D-glucosamine
17th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Gardenia Florida Fruit Extract is an extract of the fruit of the Cape Jasmine, Gardenia Florida L., Rubiaceae
18th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Urea, (2,5-dioxo-4-imidazolidinyl)-
19th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Dextrin
20th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Tocotrienol
21st on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
3,4-Dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol; .alpha.-tocopherol; Vitamin E
22nd on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Elaeis Guineensis Oil is a natural oil obtained from the fruits of the Palmoil Tree, Elaeis guineensis, Palmaceae
23rd on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Butane-1,3-diol (CAS No. 107-88-0/ EC No. 203-529-7) (R)-(-)-butane-1,3-diol” (CAS No. 6290-03-5/ EC No. 228-532-0)
24th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
L-Arginine
25th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Niacinamide (vitamin B3) is a gentle skincare active that repairs the skin barrier, calms redness, controls oil and evens tone at 2–5%. Official IUPAC name: **3-Pyridinecarboxamide**
26th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
1,2-Dihydroxypentane
27th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Alcohol Denat. is ethyl alcohol that is denatured with one or more denaturing agents in accordance with the national legislation of each European Community (EU) country.
28th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Helianthus Annuus Seed Oil is the oil expressed from the seeds of the Sunflower, Helianthus annuus L., Compositae
29th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Glycyrrhiza Glabra Root Extract is an extract of the roots of the Licorice, Glycyrrhiza glabra L., Leguminosae
30th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
1,1,1,3,5,5,5-Heptamethyl-3-(trimethylsilyloxy)trisiloxane
31st on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Carthamus Tinctorius Seed Oil is the oily liquid obtained from the seeds of Safflower, Carthamus tinctorius L., Compositae. It consists principally of the triglycerides of linoleic acid
32nd on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Camellia Japonica Seed Oil is the fixed oil expressed from the seeds of the Camellia, Camellia japonica L., Theaceae
33rd on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
Daucus Carota Sativa Root Extract is an extract of the roots of the Carrot, Daucus carota L. var. sativa, Umbelliferae
34th on the list, below the 1% line — present at under 1%, which for most ingredients is the level they work at.
.beta.,.beta.-carotene
Products in the same category that share this formula's distinguishing ingredients.
COSRX
Shares 11 key ingredients with The Vitamin C 23 serum: Water, Ascorbic Acid, Panthenol, Acetyl Glucosamine, Caffeine
IOPE
Shares 10 key ingredients with The Vitamin C 23 serum: Water, Ascorbic Acid, Dimethicone, Squalane, Caffeine
ma:nyo
Shares 9 key ingredients with The Vitamin C 23 serum: Water, Niacinamide, Glutathione, Acetyl Glucosamine, Panthenol
APLB
Shares 9 key ingredients with The Vitamin C 23 serum: Water, Propanediol, Niacinamide, Panthenol, Allantoin
Isntree
Shares 9 key ingredients with The Vitamin C 23 serum: Water, Niacinamide, Propanediol, Adenosine, Panthenol
Medicube
Shares 8 key ingredients with The Vitamin C 23 serum: Water, Propanediol, Niacinamide, Squalane, Panthenol
WATER, ASCORBIC ACID, PROPANEDIOL, DIMETHICONE, TROMETHAMINE, PANTHENOL, ETHYL ETHER, SQUALANE, CAFFEINE, SODIUM CHLORIDE, SODIUM HYALURONATE, SODIUM SULFITE, DISODIUM EDTA, GLUTATHIONE, ADENOSINE, ACETYL GLUCOSAMINE, GARDENIA FLORIDA FRUIT EXTRACT, ALLANTOIN, DEXTRIN, TOCOTRIENOLS, TOCOPHEROL, ELAEIS GUINEENSIS OIL, BUTYLENE GLYCOL, ARGININE, NIACINAMIDE, PENTYLENE GLYCOL, ALCOHOL DENAT., HELIANTHUS ANNUUS SEED OIL, GLYCYRRHIZA GLABRA ROOT EXTRACT, METHYL TRIMETHICONE, CARTHAMUS TINCTORIUS SEED OIL, CAMELLIA JAPONICA SEED OIL, DAUCUS CAROTA SATIVA ROOT EXTRACT, BETA-CAROTENE.
ASCORBIC ACID, PANTHENOL, SODIUM HYALURONATE, NIACINAMIDE.
After cleansing, during the serum phase, shake the bottle lightly once or twice from side to side. Apply a few drops to the skin. Use fingertips to gently massage and absorb the serum, starting from the inside of the face working towards the edges.
Judged on how rich the formula reads from its ingredient list, it suits Balanced skin best. It is the least natural fit for Dry, Combination (dry) skin.
No ingredient in this formula carries a common-irritant flag, making it a reasonable option for reactive skin. A patch test is still recommended, as individual skin reactivity varies.
3 ingredients could feed malassezia: Helianthus Annuus Seed Oil, Carthamus Tinctorius Seed Oil, Camellia Japonica Seed Oil. That describes the yeast's food supply, not a prediction that they will cause a breakout.
Nothing in this formula is on the standard pregnancy-caution list. That is not medical clearance — check anything you use daily with your doctor or midwife.
Yes. Reading the full ingredient list, this formula is fragrance-free.
Yes — it contains Alcohol Denat..
No — it contains Dimethicone, Methyl Trimethicone.
No. Reading the full ingredient list, this formula is essential-oil-free.
Yes. Reading the full ingredient list, this formula is paraben-free.
It layers well with Vitamin C (L-ascorbic acid), PHAs (gluconolactone), Azelaic acid, Copper peptides, Bakuchiol, Niacinamide. Take more care combining it with Benzoyl peroxide, Retinoids (retinol, retinal), AHAs (glycolic, lactic), BHA (salicylic acid) — use them in separate routines or on alternate days.
Use it morning and evening, after toner, before moisturiser.
It lists 34 ingredients, of which 4 are recorded as actives.
COSRX, a brand based in Korea.
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