The 6 Peptide Skin Booster Serum — Reddit Reviews
by COSRX
Updated November 10, 2026
Peptides and niacinamide hydrate, smooth texture, and prep layers; breakout risk.
What the community says
A watery peptide essence with niacinamide, glycerin, and sodium hyaluronate, designed for damp-skin hydration and smoother layering. It suits oily, dehydrated, or tret-treated routines, though redness, jawline breakouts, and underwhelming long-term results are recurring complaints.
What this means for you
What people love
Watch out for
Product details
Skin Type
Product Traits
Key Ingredients
What TikTok says
From 3 TikTok videos1 sponsored, marked with outlined numbers
Creators say the serum leaves skin hydrated, plump and dewy, and works as a prep step before other products 123. One sponsored creator 1 uses it as a toner or a sheet mask on dry areas, while another creator 3 advises applying it to slightly damp skin for a bigger hydration boost. A non-sponsored creator 2 rates it 6 out of 10, calling it good for layering but not very targeted.
Sponsored means the creator disclosed a brand partnership or the video ran as a paid ad.
Videos open on TikTok in a new tab.
What the science says
Peptides have some evidence for easing signs of aging, since all three studies that tested them directly found help 1. Several studies reported better wrinkles, firmness, and skin texture, though one found wrinkle changes were small 1. Reported side effects were stinging and itching, and one study noted none 1. Niacinamide has some evidence for signs of aging too, with studies showing firmer skin and fewer wrinkles and dark spots 2.
- Peptides for anti-aging Some evidence · 5 studies
- Niacinamide for anti-aging Some evidence · 8 studies
Research context, not treatment advice. Studies are about the ingredient, not necessarily this exact product.
How we grade researchFull ingredient list · 44
COSRX The 6 Peptide Skin Booster Serum ingredients
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
Listed in label order, highest concentration first. Linked ingredients have their own page.
Real Reddit threads — 177 mentions across 26 threads
COSRX The 6 Peptide Skin Booster Serum on Reddit, in one place — 26 threads from r/30PlusSkinCare, r/tretinoin and 3 more, summarized.
“CosRX The 6 Peptide Skin Booster (Hyaluronic acid).”
Positive
“At night I wash, HA, Cream”
Positive
“COSRX 6 Peptide Booster Serum”
Positive
“AM * Water Cleanse * Round Lab Dokdo Toner * COSRX 6 Peptide Booster Serum”
Positive
“Routine AM”
Positive
“Laneige Cerapeptide toner mist and also COSRX Peptide Booster.”
Positive
“I got a lot more compliments since I started using both regularly”
Positive
“since I started using both regularly”
Positive
“Other things that are working for me are the Cosrx 6 Peptide serum”
Positive
“Those items have made a big difference over the past couple of months.”
Positive
“and also their Galactomyces toner.”
Positive
“So far I've gotten: Cosrx 6 Peptide Booster”
Positive
“CosRX peptide is one of my favorite products and I love being able to get larger size!”
Positive
“The Cosrx snail is 130 ml at Costco vs 100ml at other retailers.”
Positive
“the COSRX peptide booster is my favorite!”
Positive
“So sweet 😍 the COSRX peptide booster is my favorite!”
Positive
“Has anyone tried their new PDRN serum? 🤔 any thoughts?”
Positive
Dupes & Alternatives
Anua
Azelaic Acid Hyaluron Redness Soothing Serum
Better for Redness / Irritation
14 shared traits
781 mentions
Skin1004
Madagascar Centella Asiatica Ampoule
Better for Redness / Irritation
13 shared traits
590 mentions
Often paired with
Products Redditors use alongside this one
COSRX
Low pH Good Morning Gel Cleanser
Mentioned together in 7 threads
“The 6 peptide serum is awesome and I love the low pH good morning cleanser.”