For laboratory research use only — not for human consumption
Comparison
Copper-binding tripeptide complex · Triple-agonist peptide (GLP-1 / GIP / glucagon)
GHK-Cu is a copper-binding tripeptide complex; Retatrutide is a triple-agonist peptide (GLP-1 / GIP / glucagon). They are compared here because they appear together in research catalogues, not because they are interchangeable. GHK-Cu is studied in copper-peptide & matrix-signalling research, Retatrutide in metabolic & receptor-signalling research. This page sets out structure, identifiers and research context only; it makes no human-use, dosing, or therapeutic claim. Both are supplied for in-vitro laboratory research use only.
| GHK-Cu | Retatrutide | |
|---|---|---|
| Class | Copper-binding tripeptide complex | Triple-agonist peptide (GLP-1 / GIP / glucagon) |
| Research area | Copper-peptide & matrix-signalling research | Metabolic & receptor-signalling research |
| CAS number | 49557-75-7 | 2381089-83-2 |
| Molecular formula | C14H22CuN6O4 | C221H342N46O68 |
| Sequence | Gly-His-Lys · Cu(II) | — |
| HPLC purity | 99.72% | 99.66% |
The two sit in different structural families. GHK-Cu is classified as a copper-binding tripeptide complex, while Retatrutide is a triple-agonist peptide (GLP-1 / GIP / glucagon). That difference is the substantive one: it means the two are not variants of a single scaffold, and any protocol that substitutes one for the other is changing the compound class under study, not simply swapping a reagent of the same type.
Their research framing also diverges. GHK-Cu is catalogued under copper-peptide & matrix-signalling research, whereas Retatrutide is catalogued under metabolic & receptor-signalling research. Investigators therefore tend to encounter the two in separate literatures, and any observation reported for one should not be read across to the other — findings belong to the studies and models that produced them.
Only one of the two is catalogued here with an explicit amino-acid sequence. GHK-Cu is listed as Gly-His-Lys · Cu(II), while Retatrutide is identified by molecular formula and CAS number instead — the usual convention for larger or heavily modified peptides, where the formula and the mass-spectrometry result carry the identity rather than a written residue string.
The molecular formulae differ accordingly — GHK-Cu is C14H22CuN6O4 and Retatrutide is C221H342N46O68 — with Retatrutide being the larger molecule of the two and GHK-Cu the more compact. Molecular size is worth noting when planning reconstitution and storage, since molar concentration for a given vial mass is not the same across the two.
Characterisation is closely matched: 99.72% HPLC purity for the current GHK-Cu batch and 99.66% for Retatrutide. Purity is a batch-specific figure rather than a property of the compound, so the Certificate of Analysis for the batch actually received is what belongs in a method section.
The two sit in distinct research areas — copper-peptide & matrix-signalling research for GHK-Cu, metabolic & receptor-signalling research for Retatrutide — so the lists below have little in common. These are areas of scientific study reported in the primary literature, not effects.
These are structurally distinct compounds studied in different contexts, so they are complements rather than substitutes. GHK-Cu is the appropriate reference reagent where the question concerns copper-peptide & matrix-signalling research and the copper-binding tripeptide complex scaffold; Retatrutide is appropriate where the question concerns metabolic & receptor-signalling research and the triple-agonist peptide (GLP-1 / GIP / glucagon) scaffold.
Whichever is selected, the practical criteria are the same and are documentary rather than comparative: that the CAS number and molecular formula match what the protocol specifies, that a current per-batch Certificate of Analysis is on file, and that handling and storage follow the notes published on each monograph. Nothing on this page ranks one compound above the other, and neither is characterised for, or supplied for, any use outside in-vitro laboratory research.
Each compound has its own research monograph with the complete overview, studied-in list and laboratory handling notes, and a product page carrying the current batch COA.
Copper-binding tripeptide complex · CAS 49557-75-7
The tripeptide was first isolated from human plasma fractions in the 1970s during work on factors that differed between plasma from younger and older donors, and the copper-binding behaviour was characterised shortly afterwards.
Triple-agonist peptide (GLP-1 / GIP / glucagon) · CAS 2381089-83-2
Structurally it is a 39-residue peptide (molecular formula C221H342N46O68, CAS 2381089-83-2) carrying a fatty-acid moiety that extends its half-life in solution — a feature that makes it a useful comparator in peptide-stability and receptor-pharmacology research.
Both compounds are supplied strictly for in-vitro laboratory research use only. Not for human or veterinary use. This comparison is structural and contextual and does not constitute advice on use.