Tissue Repair & Regeneration

Tetrapeptide-21

Tetrapeptide-21 is four amino acids — glycine, glutamate, lysine, glycine — and what makes it interesting in the dish is breadth: in fibroblast culture it raises collagen, hyaluronan and fibronectin together rather than one of the three, and the supplier reports roughly twice the collagen response of Matrixyl. Getting a peptide from a cream down into the dermis is the hard half of that argument, and two of the four graded studies on file are about exactly that — a hydrogel delivery system, and a penetration study across excised human skin. Every graded study here is cell-culture or ex-vivo work, and no human trial of it is recorded.

Last updated 12 August 2026

Studied forCollagen synthesis research · Hyaluronic acid research · Skin roughness context

Evidence on file1 animal study · 2 in-vitro studies · 1 computational study

Strongest sourceElastin-derived peptide hydrogels for sustained dermal delivery of tetrapeptide-21. (animal study)

Mechanism

Upregulates collagen at mRNA and protein level in dermal fibroblasts, alongside hyaluronan and fibronectin synthesis.

Reported effects

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

Collagen synthesis research
Hyaluronic acid research
Skin roughness context

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 incidecoder: "superior collagen, hyaluronic acid and fibronectin boosting activity"; in vitro "collagen production in the presence of Tetrapeptide-21 was almost 2-fold higher" vs Matrixyl; in vivo (n=60, 8 weeks) "Tetrapeptide-21 performed better after 8 weeks for skin volume, roughness and elasticity" vs Matrixyl; 60-person 4% study showed "visible-to-the-naked-eye wrinkle reduction around the eye area".

Manufacturer: Not confirmed on fetched pages (TEGO is widely associated with Evonik, but the Evonik product URL redirected to a generic page and no fetched page named the owner)
Sold as: TEGO Pep 4-17
Manufacturer’s recommended use: Tested at 0.5%, 4% and 5% per incidecoder; no official recommendation stated

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

Dosing on file unverified

0.01-0.05% cream; 10-100 ppm, 2x/day (8 weeks)

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 4

animal in vivo
Elastin-derived peptide hydrogels for sustained dermal delivery of tetrapeptide-21. graded on: an animal model — read from the indexed abstract — “swine”
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”
in vitro
Synergistic Effects of Injectable Platelet-Rich Fibrin and Bioactive Peptides on Dermal Fibroblast Viability and Extracellular Matrix Gene Expression: An In Vitro Study. graded on: an in-vitro system — “In Vitro”
in vitro
Dermal peptide delivery using enhancer molecules and colloidal carrier systems. Part III: Tetrapeptide GEKG. graded on: ex vivo penetration studies in excised human skin across formulations — read from the abstract — “abstract review”

Identity

Space-filling 3D model of Tetrapeptide-21, 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 Tetrapeptide-21 — 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: 389.40
Molecular formula: C15H27N5O7
CAS number: 960608-17-7
PubChem CID: 42630677
InChI key: CUVSTAMIHSSVKL-UWVGGRQHSA-N
SMILES: C(CCN)C[C@@H](C(=O)NCC(=O)O)NC(=O)[C@H](CCC(=O)O)NC(=O)CN
InChI: InChI=1S/C15H27N5O7/c16-6-2-1-3-9(14(26)18-8-13(24)25)20-15(27)10(4-5-12(22)23)19-11(21)7-17/h9-10H,1-8,16-17H2,(H,18,26)(H,19,21)(H,20,27)(H,22,23)(H,24,25)/t9-,10-/m0/s1

Also called

TEGO Pep 4-17
Tetrapeptide-21

Notes unverified prose

8-week in vivo study (n=60): outperformed Matrixyl for skin volume, roughness, elasticity; 0.05%: nasolabial fold depth -19%; In vivo study (n=60, 8 weeks) outperformed Matrixyl

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.