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COSRX The 6 Peptide Skin Booster Serum ingredients: is it worth it?
A well-built hydrating peptide booster, but the marketing promises more than the evidence can justify.
A well-built hydrating peptide booster, but the marketing promises more than the evidence can justify.
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The 4.0/5 efficacy score comes from a strong humectant and amino-acid base, niacinamide in position 6, sodium hyaluronate, acetyl glucosamine, allantoin, and several legitimate peptide technologies placed unusually high for a peptide serum. The score is capped because the formula does not disclose peptide concentrations, lacks a clearly established retinoid or high-evidence vitamin C treatment, and most peptide claims are difficult to translate into predictable visible results at undisclosed levels. Its likely acidic-to-mildly acidic pH should support niacinamide and overall tolerability, but the exact pH is not published. The 4.5/5 safety score reflects the absence of fragrance, essential oils, harsh exfoliating acids, and denatured alcohol; t-butyl alcohol is present near the end of the list, so highly reactive skin may still prefer a patch test. The marketed peptides are not being credited as guaranteed wrinkle correction; the dependable benefits here are hydration, conditioning, and modest barrier/tone support.
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DemythSkin rates COSRX The 6 Peptide Skin Booster Serum 4.2/5 for efficacy and 4.6/5 for safety.
ACTIVE INGREDIENTS BY TIER
Gold Standards
High clinical proof | Skin-transformativeReliable
Proven resultsPotent
Developing evidenceOverhyped | Marketing
Hype | Limited dataDocumented Irritants
Evidence-backed flagFORMULATION BASE (16)⌄
FULL INGREDIENT LIST⌄
Water, Dipropylene Glycol, Glycerin, Pentylene Glycol, 1,2-Hexanediol, Niacinamide, Acetyl Hexapeptide-8, Copper Tripeptide-1, sh-Polypeptide-121, Dipeptide Diaminobutyroyl Benzylamide Diacetate, Oligopeptide-68, Palmitoyl Tripeptide-8, Allantoin, Sodium Hyaluronate, Acetyl Glucosamine, Serine, Alanine, Glycine, Threonine, Arginine, Proline, Betaine, Sodium PCA, Sodium Lactate, PCA, Glutamic Acid, Lysine HCl, Tocopherol, Dextran, Glycine Soja (Soybean) Oil, Hydrogenated Lecithin, Ammonium Acryloyldimethyltaurate/VP Copolymer, Polyacrylate Crosspolymer-6, Butylene Glycol, Xanthan Gum, Ethylhexylglycerin, Adenosine, Polyquaternium-51, Disodium EDTA, Citric Acid, Caprylyl Glycol, t-Butyl Alcohol, Potassium Sorbate, Sodium Oleate
WHAT EACH INGREDIENT DOES (24)⌄
- Water
- Formula solvent
- Dipropylene Glycol
- Solvent and humectant
- Glycerin
- Humectant
- Pentylene Glycol
- Humectant and solvent
- 1,2-Hexanediol
- Solvent and preservative booster
- Niacinamide
- Barrier and tone support
- Acetyl Hexapeptide-8
- Expression-line peptide
- Copper Tripeptide-1
- Signal peptide
- sh-Polypeptide-121
- Recombinant signaling peptide
- Dipeptide Diaminobutyroyl Benzylamide Diacetate
- Expression-line peptide
- Oligopeptide-68
- Signaling peptide
- Palmitoyl Tripeptide-8
- Soothing signal peptide
- Allantoin
- Soothing skin protectant
- Sodium Hyaluronate
- Humectant
- Acetyl Glucosamine
- Barrier and tone support
- Serine
- Natural moisturizing factor
- Alanine
- Natural moisturizing factor
- Glycine
- Natural moisturizing factor
- Threonine
- Natural moisturizing factor
- Arginine
- Amino acid conditioner
- Proline
- Natural moisturizing factor
- Betaine
- Osmolyte humectant
- Sodium PCA
- Natural moisturizing factor
- Sodium Lactate
- Humectant and pH adjuster
EXTERNAL CITATIONS
Niacinamide: Well-studied topical vitamin B3 for barrier support, sebum regulation, and uneven-tone improvement
Sodium Hyaluronate: Hyaluronic-acid salt used as a topical humectant for temporary hydration and skin plumping
Acetyl Glucosamine: Topical amino-sugar with evidence for barrier support and complementary uneven-tone improvement
Allantoin: Established skin-conditioning and soothing ingredient
Adenosine: Topical cosmetic ingredient with limited-to-moderate evidence for smoothing the appearance of fine lines
DISCLAIMER: THIS ANALYSIS IS FOR INFORMATION ONLY. NOT MEDICAL ADVICE. AI-GENERATED DATA BASED ON PUBLICLY AVAILABLE INGREDIENT LISTS. VERIFY WITH A MEDICAL PROFESSIONAL.
A cheaper serum that scores as high or higher
A different formula for the same concern (hydration) that scores at least as high on both efficacy and safety.
COSRX The 6 Peptide Skin Booster Serum: common questions
Is COSRX The 6 Peptide Skin Booster Serum worth it?
COSRX The 6 Peptide Skin Booster Serum scores 4.2 out of 5.0 for efficacy (Effective) and 4.6 out of 5.0 for safety (Very Gentle) on DemythSkin's independent ingredient analysis. A well-built hydrating peptide booster, but the marketing promises more than the evidence can justify.
What are the key active ingredients in COSRX The 6 Peptide Skin Booster Serum?
COSRX The 6 Peptide Skin Booster Serum contains no gold-standard actives. Its formula is built on supporting and base ingredients rather than clinically transformative actives.
Does COSRX The 6 Peptide Skin Booster Serum contain fragrance or known irritants?
DemythSkin flags these ingredients in COSRX The 6 Peptide Skin Booster Serum as documented irritants: t-Butyl Alcohol.
How is COSRX The 6 Peptide Skin Booster Serum scored?
DemythSkin grades every product on two independent scores: efficacy (whether the ingredients have clinical evidence of working) and safety (irritation and sensitisation risk). Ingredients are graded S through D against a database of over 3,000 compounds. Brand and price are not part of the score, and no brand pays for one.
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