AHK-Cu supplier checklist: what the lot certificate has to show

What is AHK-Cu, and what is it not?

AHK-Cu is two things in one vial: the tripeptide alanyl-L-histidyl-L-lysine, three residues, 354.2 Da as the bare peptide (PubChem CID 7408502), and a copper(II) ion held by the histidine imidazole, the alanine amine and the backbone. It differs from GHK-Cu by one residue, alanine in place of glycine, which adds 14 Da and a methyl group and otherwise leaves the coordination the same. Listings write AHK-Cu, AHK Cu, copper tripeptide AHK and AHK copper peptide; the free peptide without copper is AHK and is a different, colorless material. Like GHK-Cu, the copper complex is blue-violet as a powder and blue in solution.

The two copper tripeptides get marketed as interchangeable, and the published record does not support treating them that way: GHK-Cu has decades of cell and skin-model literature, while the AHK-Cu record is a handful of papers, the one cited at the foot of this page among them. This page makes no claim about what either does. What it can say precisely is that AHK-Cu is a defined complex with a known peptide mass and a known copper ratio, and that both are measurable.

The buying problem is the same as for GHK-Cu and slightly worse, because the compound is rarer and certificates for it are more often templates. A 1:1 AHK-Cu complex is about 15.3% copper by mass (63.5 Da of copper in a 416 Da complex); a powder with a few percent copper is free peptide with copper salt stirred in, sold at complex prices, and only a copper assay on the certificate shows the difference.

The reference point for identity is public. PubChem lists L-alanyl-L-histidyl-L-lysine (free tripeptide) as CID 7408502 with molecular formula C15H26N6O4, an average molecular weight of 354.41 Da and a monoisotopic mass of 354.202 Da. Those are the numbers a mass spectrometer is checked against, and the number a certificate must print beside the observed mass. Free peptide Ala-His-Lys. The copper complex is a coordination compound; PubChem has no single canonical record for it, so identity is confirmed on the peptide and copper is reported separately.

In plain terms: A three-building-block peptide (alanine, histidine, lysine) joined to copper. No approved product, and a noticeably thinner evidence base than its better-known relative. The two get marketed as interchangeable; the published record does not support treating them that way.

AHK-Cu sizes: what does each size cost per mg?

LabFirst lists AHK-Cu in 2 sizes (20mg, 50mg) from $50 to $60, priced per vial with the per-mg figure beside it so sizes can be compared without arithmetic. Per mg, the 50mg vial is the cheapest at $1.20 and the 20mg the dearest at $2.50, which is the usual shape; the table below is the arithmetic, and the per-mg column, not the vial price, is the one to compare.

The volume tiers are per size, not per basket: ten vials of one size take 10% off that line and twenty take 15%, and mixed sizes do not combine. Ground Advantage shipping is a flat $15 on orders under $200 and free from $200, within the United States only, with same-day dispatch on orders placed before 12 PM Pacific on a business day. The cost per mg tool runs the same comparison across any two listings, ours or anyone else's.

AHK-Cu is cheap to make, three ordinary residues and a copper salt, and its price per milligram is among the lowest in the catalog, which is why LabFirst sells it in 20 mg and 50 mg vials rather than single-digit sizes; the vial, the drying run and the laboratory work are almost the whole cost, and the per-milligram figure falls steeply from the smaller vial to the larger. A laboratory qualifying a lot buys the 20 mg vial once and reads the peptide mass and the copper percentage on its certificate before buying larger.

The price signal is the copper assay. A certificate that carries a copper percentage means the seller paid for a second test on a cheap compound; a certificate that does not is the cheaper certificate to buy, and the powder it describes may be the cheaper powder to make. Comparing two AHK-Cu listings per milligram without knowing the copper content of each compares two numbers that measure different things. The only discounts on this page are the volume tiers, per size and unchanged month to month.

What should an AHK-Cu certificate show?

Three tests answer three different questions, and a certificate of analysis for AHK-Cu is only complete when it carries all three for the exact lot on the vial. Identity is settled by mass spectrometry, and the number to look for on an AHK-Cu certificate is 354.202 Da monoisotopic (or 354.41 Da average, if the laboratory reports the deconvoluted average mass). The observed mass should sit within the instrument's stated tolerance of that figure, and the certificate should print both the theoretical and the observed value, not just a tick.

Purity is a separate question, answered by HPLC: how much of what came off the column was the compound. The figure is only interpretable with its method beside it (column, gradient, detection wavelength) and a date, which is what ICH Q2(R2) means when it asks that an analytical procedure be shown fit for its purpose. A percentage with no method and no date is a number somebody typed, and a certificate that carries every test but for a different lot number than the vial is the most common failure of all and the easiest to catch. Net content is the third test and the one most often missing: the milligrams of AHK-Cu actually in the vial, measured, against the size printed on the label.

An AHK-Cu certificate needs two identities. The peptide is confirmed by mass spectrometry, 354.202 Da monoisotopic for the free tripeptide (formula C15H26N6O4), seen as m/z 355.2 for the singly charged ion; a laboratory may report the intact complex instead, about 416 Da for the 1:1 cation, and either is acceptable if the certificate says which. A mass of 340 Da is GHK, not AHK: the two differ by 14 Da, and a factory that ships GHK-Cu under the AHK-Cu name is caught by that number alone. The copper is confirmed separately by ICP-OES, atomic absorption or complexometric titration and reported as a percentage of the powder, near 15.3% for a stoichiometric complex.

Purity by HPLC is read with the caution particular to copper peptides: the complex can dissociate on a reversed-phase column depending on the mobile phase, so the chromatogram may show the free peptide even when the vial held the complex, and a laboratory that knows the compound states the conditions and what the main peak is. Net content should be given as peptide, as copper, or as complex, and the certificate must say which; a 20 mg vial can be 20 mg of complex (about 17 mg of peptide) or 20 mg of peptide (about 23 mg of complex), and the price per milligram moves by a sixth between those two readings.

Checking a supplier of AHK-Cu: five checks before you order

Every seller of ahk-cu peptide says "third-party tested". The phrase costs nothing. These five checks take about four minutes per listing and separate a tested lot from a tested-sounding one.

1. The lot on the vial is the lot on the certificate. Read the printed lot number, then open the certificate and match it. A certificate for "AHK-Cu" with no lot, or a lot that does not match, describes some other vial.
2. The laboratory is named and has its own lookup. The report should come from a laboratory the seller does not own, with a search code you can enter on the laboratory's own site. LabFirst lots are tested by an independent laboratory and the laboratory's report is published for each lot; anything that exists only as the seller's own summary has not been verified.
3. The theoretical mass is printed, and it is the right one. For AHK-Cu that is 354.202 Da monoisotopic; a certificate that prints a different figure has either measured a different molecule or copied a template.
4. Purity has a method and a date. An HPLC percentage should name the method and the run date. A figure that reads "99%+" with neither, or one date reused across every product a seller lists, is decoration.
5. Net content is stated in milligrams. The label size is a claim; the certificate's net content is the measurement. If the certificate has no net content line, the purity figure describes the powder, not the vial, and the price per mg you calculated is fiction.

How listings for AHK-Cu specifically mislead:

• GHK-Cu shipped as AHK-Cu. The two differ by 14 Da (340 against 354 for the free peptide); a certificate that prints the peptide mass catches the swap, and one that prints only a color and a purity does not.
• White powder or a clear solution sold as AHK-Cu. The copper complex is blue-violet in the vial and blue in solution; a colorless product is AHK without copper, or something else.
• A certificate with a peptide mass and no copper assay. The copper is half the identity; without a copper percentage the ratio, and therefore the product, is unknown.
• Copy that borrows GHK-Cu's literature for AHK-Cu. The two are relatives with very different research records; a certificate describes the vial, and the vial is AHK-Cu or it is not.

How do I verify a LabFirst AHK-Cu lot?

The AHK-Cu sizes in stock today carry lot LF-03A-2609. Lot LF-03A-2609 is at the laboratory for identity, purity and net content. Until the report is attached the product page says "pending verification" against that lot and makes no purity claim; the price stands and the report goes live the day it arrives, on the page and at /coa/.

Verification runs through the laboratory, not through us. Open the certificate index, find the lot, and read the laboratory's report; it is the laboratory's own document, not ours, and the laboratory will confirm it against its records.

The product page reads the live stock feed on load (stock, lot and certificate state for every size), so what you see when you order is what ships. The lot is printed on the label and encoded in the QR patch on its right-hand side; scanning it opens that lot's record.

How should AHK-Cu be stored, and how does it ship?

Dry AHK-Cu is a stable blue-violet powder when sealed and refrigerated at 2 to 8 C out of light, and its color is the built-in indicator: a cake that has turned green or brown has taken on water or lost its copper coordination. The complex is hygroscopic, more so than a bare peptide, so a vial opened in humid air should be used and not re-sealed for storage. The copper is the reactive part of the complex; it binds to anything that chelates metal, including phosphate buffers, EDTA and some plastics. Blue means intact; anything else means ask the certificate what changed.

Orders ship within the United States, Ground Advantage at a flat $15 under $200 and free above it, same day when placed before 12 PM Pacific on a business day, and the shipping page states the cutoff, the carriers and what is and is not promised.

The record a laboratory keeps on arrival is what makes the certificate usable later, and it is short:

• the lot number as printed on the vial, and the certificate's accession or search code beside it;
• the date received and the condition of the seal;
• the storage location and temperature it went into;
• the number of vials, and later the date each one was opened and by whom.

An AHK-Cu vial with that record behind it can be traced from the bench to the laboratory report in one step; without it, the certificate is a document about a vial that can no longer be identified.

What is the regulatory status of AHK-Cu?

No approved medicine contains AHK-Cu and no USP or Ph. Eur. monograph defines an acceptable lot. Unlike its relative GHK-Cu, AHK-Cu was not among the substances the FDA moved to Category 2 of its interim 503A bulk substances list in September 2023, which means only that it was not on that list, not that any standard exists for it; the FDA page cited below carries the current entries, and they concern pharmacies rather than laboratory vials. It is sold here as laboratory material only, and the copper assay on the certificate is the only thing that says what a vial of it contains.

FOR LABORATORY AND IN-VITRO RESEARCH USE ONLY. NOT FOR HUMAN OR ANIMAL CONSUMPTION. LabFirst sells AHK-Cu to laboratories and researchers as material for in-vitro work, gives no guidance on use, and ships only against that understanding. Nothing on this page or on the product page describes preparing or administering anything.

Bottom line

Buy AHK-Cu only from a listing whose certificate matches the lot on the vial and reports two things: the peptide mass, 354.202 Da monoisotopic, and a copper percentage near 15.3%. A blue-violet powder is a good sign and proves nothing on its own. Compare prices per milligram only once you know each listing measured the same thing.

What is AHK-Cu studied for?

Published research on AHK-Cu investigates the areas below, which is a different question from what AHK-Cu will do for anyone, a claim about a living system that nothing on this site is sold for.

What it is. A three-building-block peptide (alanine, histidine, lysine) joined to copper.

What the research looks at. A smaller body of cell-culture work than GHK-Cu, on copper-peptide chemistry and skin structure.

How it is thought to work. A close relative of GHK-Cu, differing at the first building block. Like GHK-Cu it grips copper, and the copper-carrying form is what has been studied.

What is not established. No approved product, and a noticeably thinner evidence base than its better-known relative. The two get marketed as interchangeable; the published record does not support treating them that way.

The full record, including the certificate for the lot in stock, is on the AHK-Cu product page.

Common questions

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Sources

• PubChem, L-alanyl-L-histidyl-L-lysine (free tripeptide), CID 7408502. Public record for the molecular formula (C15H26N6O4), average molecular weight (354.41 Da) and monoisotopic mass (354.202 Da) quoted here as the identity reference.
• Pyo and colleagues, The effect of tripeptide-copper complex on human hair growth in vitro, Archives of Pharmacal Research 2007. Primary description of the compound in the literature; supports the class and naming stated here, not any use.
• FDA, Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act. The FDA page that carries the current 503A category lists; read for AHK-Cu's entry rather than assumed.
• ICH Q2(R2), Validation of Analytical Procedures (2023) 2023-11. Why a purity figure is only interpretable with its method, and what "fit for purpose" means for the HPLC and mass spectrometry results a certificate reports.