Tissue Repair & Regeneration

Acetyl Tetrapeptide-5

Acetyl tetrapeptide-5, sold as Eyeseryl, goes after under-eye puffiness from two directions at once. It inhibits angiotensin-converting enzyme, the same target as a whole prescribed class of blood-pressure drugs, to slow fluid leaking out of small vessels; and it blocks glycation, the sugar-driven stiffening of collagen. For a cosmetic ingredient that is an unusually specific mechanism. The figures quoted for it are less specific in origin — seven participants in ten with puffiness down by at least 30 per cent at day 15, volume down 29.7 per cent at 28 days, all from manufacturer studies. The human papers on file test injectable mixtures of several peptides at once.

Last updated 12 August 2026

Studied forUnder-eye puffiness research · Anti-glycation context · Skin firmness support

Evidence on file2 human observational studies · 1 human case report or series · 1 computational study · 1 citation not yet graded

Strongest sourceQuantitative Ultrasonographic and Shear Wave Elastographic Assessment of Infraorbital Tissue Changes After No… (human observational study)

Mechanism

Inhibits angiotensin-converting enzyme 1 and protein glycation, reducing capillary permeability and cross-linking of dermal collagen.

Reported effects

What sources associate with this compound. Reported categories, not outcomes we have graded — each would need its own citation and rung.

Under-eye puffiness research
Anti-glycation context
Skin firmness support

Manufacturer’s claim vendor marketing

For a proprietary cosmetic ingredient the manufacturer is the originator — there is no upstream to defer to, and this is often the only description that exists. It is reproduced as an attributed claim, with the label its source gave it. It is not graded and it is not evidence — the graded studies are under Literature.

Vendor claims quoted from fetched page: "By day 15, 70% of participants showed a >=30% reduction in puffiness. By day 60, 95% of participants showed improvement."; "Under-eye puffiness volume decreased by up to 29.7% after 28 days"; "Skin elasticity around the eyes increased by 30% over 30 days". Fetched page describes a trial of 20 female volunteers aged 18-65, 0.01% twice daily for 60 days, and a separate trial of 20 females aged 45-60 with "62% reporting medium to very marked improvement".

Manufacturer: Lipotec (acquired by Lubrizol)
Sold as: Eyeseryl
Manufacturer’s recommended use: Vendor claim: "1-10% in skincare products (0.01-0.1% pure peptide)"

Source page — nofollow, because a vendor link is a reference here, not an endorsement.

Dosing on file unverified

0.001-0.01% cream, 1-2x/day (Eyeseryl)

Carried from a source that labels it unverified, and reproduced with that label attached. A record of what is reported, not a recommendation. No citation on this page establishes it.

Literature on file 6

review or editorial
The Clinical Evidence-Based Paradigm of Topical Anti-Aging Skincare Formulations Enriched with Bio-Active Peptide SA1-III (KP1) as Collagen Modulator: From Bench to Bedside. graded on: indexed as "review-article" - secondary literature, not a study — “review-article”
human case series
The Combined Benefits of Definisse™ Revitalise Threads and Definisse [KP1]® Redensifying Cream Treatments: A 19-Patient Case Series. graded on: a case report or series — “Case Series”
computational
A framework for the safety evaluation of peptides in cosmetics. graded on: in-silico safety framework applied through six bioinformatic tools — read from the abstract — “abstract review”
human observational
Quantitative Ultrasonographic and Shear Wave Elastographic Assessment of Infraorbital Tissue Changes After Non-cross-linked Hyaluronic Acid and Amino Acid Therapy. graded on: prospective single-arm interventional, n=40, within-subject baseline — read from the abstract — “abstract review”
human observational
Safety and Efficacy of an Injectable Solution Enriched With Sodium Hyaluronate, Amino Acids, and Peptides in Relation to Superficial Facial Connective Tissues (Dermis and Retinacular Cutis). graded on: an observational human design — the indexed publication type — “Observational”

Not graded

1 citation whose study design could not be read from the title. Left ungraded rather than guessed at.

not graded
MANUFACTURER_DATA_ONLY

Identity

Space-filling 3D model of Acetyl Tetrapeptide-5, carbon grey, nitrogen blue, oxygen red — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

2D chemical structure of Acetyl Tetrapeptide-5 — Built from the SMILES on this record — the atoms and bonds are exact. The shape is **one computed low-energy pose**, not a measured structure: a flexible peptide in solution has no single conformation, and where the SMILES leaves a stereocentre undefined the pose commits to one arbitrarily. The skeletal formula below claims connectivity and nothing more, which is what we actually know.

Molecular weight: 492.5
Molecular formula: C20H28N8O7
CAS number: 820959-17-9
PubChem CID: 11620163
InChI key: ROTFCACGLKOUGI-JYJNAYRXSA-N
SMILES: CC(=O)NCCC(=O)N[C@@H](CC1=CN=CN1)C(=O)N[C@@H](CO)C(=O)N[C@@H](CC2=CN=CN2)C(=O)O
InChI: InChI=1S/C20H28N8O7/c1-11(30)23-3-2-17(31)26-14(4-12-6-21-9-24-12)18(32)28-16(8-29)19(33)27-15(20(34)35)5-13-7-22-10-25-13/h6-7,9-10,14-16,29H,2-5,8H2,1H3,(H,21,24)(H,22,25)(H,23,30)(H,26,31)(H,27,33)(H,28,32)(H,34,35)/t14-,15-,16-/m0/s1

Also called

Acetyl Tetrapeptide-5
Eyeseryl

Notes unverified prose

28-60 day studies: under-eye puffiness reduction 32-70%; skin elasticity +35%; manufacturer studies (Lipotec, n~20-30); 28-day study (0.001%, 34-54 yrs); Lipotec Eyeseryl

Not on file 2

1 of the 8 fields we track hold nothing on this record, and each says why. 1 further absence is named below. A blank field is a bug; a named absence is a finding.

amino-acid sequencenothing we hold supplies it
half-lifenothing we hold supplies it

Each field links to every other record missing the same thing. The full ledger holds 765 gaps across 163 records.