AHK-Cu is a copper-bound tripeptide (alanine-histidine-lysine) sold for hair-follicle research. Its entire published evidence base is one 2007 laboratory study on human hair follicles and cultured cells; no human trial exists. This guide separates what that study measured from what is repeated about it. Educational use only, not medical advice.
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AHK-Cu Guide: Available Now
Educational use only — not medical advice. This guide summarizes information reported in published research and community practice for educational purposes. It is not medical advice and not a recommendation to use any compound. Any doses, schedules, or combinations shown are examples of what has been reported, not instructions for you. Many peptides described here are research compounds that are not FDA-approved for the uses discussed and may be investigational or restricted. Effects, risks, and legal status vary; individual needs and results vary. Consult a qualified, licensed healthcare professional before making any decision. Do not use this content to diagnose, treat, or dose yourself.
AHK-Cu at a glance
What it is
L-alanyl-L-histidyl-L-lysine bound to a copper(II) ion. PubChem: the complex, as its monohydrochloride, is CID 168431292 (C15H24ClCuN6O4, 451.4 g/mol, CAS 682809-81-0); the copper-free peptide AHK is CID 7408502 (C15H26N6O4, 354.4 g/mol, CAS 126828-32-8, UNII 1AVY5QO8WR). Sold in cosmetics as "copper tripeptide-3"
Researched for
Hair growth, in one laboratory study: human scalp hair follicles kept alive in culture and dermal papilla cells grown in a dish (Pyo et al., Arch Pharm Res 2007, PMID 17703734). No study in people or animals has been published
Plasma half-life
Never measured in any species. The "cleared within hours" estimate this page previously gave had no source and is withdrawn
Regulatory status
Not approved as a medicine anywhere and no US drug label. Unlike its relative GHK-Cu, it is not on either FDA compounding list or FDA's safety-risk page. Not named by WADA, but section S0 covers substances with no approval for human therapeutic use
Educational reference. This page does not publish dose ranges or reconstitution arithmetic.
What it is / mechanism
AHK-Cu is the three-amino-acid peptide alanine-histidine-lysine with a copper(II) ion held by the histidine and the peptide backbone. It is a close relative of GHK-Cu (glycine-histidine-lysine copper), differing in the first amino acid, and it is sold on the idea that the copper-peptide biology described for GHK-Cu in skin can be pointed at the hair follicle. Two identity details matter when checking a product against a registry. First, the copper-free peptide and the copper complex are separate records: AHK alone is PubChem CID 7408502 (C15H26N6O4, about 354.4 g/mol, CAS 126828-32-8), while the name AHK-Cu resolves to CID 168431292, filed as the copper complex's monohydrochloride (C15H24ClCuN6O4, about 451.4 g/mol, CAS 682809-81-0). A certificate of analysis should say which of the two its mass and purity refer to, and whether copper was measured. Second, "copper tripeptide-3" is the name cosmetic suppliers use for that same CAS number, but PubChem does not list it as a synonym, so a search on the cosmetic name alone finds nothing. What the one study actually measured is narrower than the mechanism usually attributed to it. Pyo et al. (2007) report that AHK-Cu at 10⁻¹² to 10⁻⁹ M lengthened human hair follicles kept in culture and increased the proliferation of dermal papilla cells, the specialised fibroblasts at the base of the follicle. In those cells, 10⁻⁹ M raised the ratio of the anti-apoptotic protein Bcl-2 to the pro-apoptotic Bax and lowered cleaved caspase-3 and PARP, markers of programmed cell death; the fall in the number of dying cells itself was not statistically significant. The effects on blood-vessel growth factor (VEGF) and TGF-β1 that are often attached to AHK-Cu come from earlier work on tripeptide-copper complexes in skin fibroblasts, which the paper cites as background — they were not measured on hair follicles in this study. These are laboratory observations, not demonstrated effects in people.
Researched effects
In the one published study, AHK-Cu made human hair follicles grow longer in culture and made dermal papilla cells multiply faster, across a concentration range of one picomolar to one nanomolar (Pyo et al., Arch Pharm Res 2007, PMID 17703734). That is the whole of the published evidence. No study has applied AHK-Cu to anyone's scalp, injected it into a person or an animal, or measured hair count, hair density or shedding in a living organism. Claims that it thickens hair, extends the growth phase in people or works better than GHK-Cu are marketing and community anecdote, not study results. Two statements this page previously made are withdrawn: that the study showed a biphasic response in which higher concentrations inhibited growth (its published abstract reports stimulation across the range tested and no inhibition, and we could not trace the inhibition claim to any publication), and that it extends the follicle's growth (anagen) phase in tissue models (the study did not measure hair-cycle phase).
Evidence & regulatory status
One study, in a dish. Pyo HK, Yoo HG, Won CH et al., "The effect of tripeptide-copper complex on human hair growth in vitro", Arch Pharm Res 2007;30(7):834-9 (PMID 17703734; Seoul National University Department of Dermatology). Human scalp hair follicles kept alive in organ culture and cultured dermal papilla cells were exposed to AHK-Cu at 10⁻¹² to 10⁻⁹ M. Follicles lengthened and papilla cells proliferated. At 10⁻⁹ M, the Bcl-2/Bax ratio rose and cleaved caspase-3 and PARP fell; the reduction in apoptotic cells measured by flow cytometry was not statistically significant.
What the study did not measure: hair-cycle phase (anagen or catagen), VEGF or any growth factor in the follicle, hair growth in a living animal or person, or any concentration above 10⁻⁹ M. The widely repeated "biphasic" claim — stimulation at low concentrations, inhibition at higher ones — is not in the study's published abstract and we found it in no other publication, so it is withdrawn here.
The literature is one paper deep. On 24 September 2026 a PubMed search for "AHK-Cu" or "copper tripeptide-3" returned that single paper. Searches pairing the peptide's full name with copper return copper-binding chemistry — mostly on DAHK, a fragment of human albumin — and nothing on hair or skin. The same search for GHK-Cu and its synonyms returned 212 records, so the search works; AHK-Cu is simply unstudied.
No human trials. ClinicalTrials.gov returns no study for "AHK-Cu" or "copper tripeptide" (the same site returns 758 for semaglutide as an intervention). The records a search on "Ala-His-Lys" returns are unrelated amino-acid and nutrition studies that match on the words, not on the peptide.
Regulatory, United States: AHK-Cu is on neither FDA list of bulk substances nominated for compounding — the 503A list for pharmacies (updated 14 May 2026) or the 503B list for outsourcing facilities (updated 21 March 2025) — and it is not on FDA's page of bulk substances that may present significant safety risks (current as of 22 April 2026). Its relative GHK-Cu is on both: the injectable form is on the safety-risk page, with FDA citing possible immunogenicity from aggregation and peptide-related impurities, and non-injectable GHK-Cu is back in 503A Category 1, under evaluation. Absence from these lists means nobody has asked FDA about AHK-Cu, not that FDA has cleared it. An openFDA drug-label search for AHK-Cu or copper tripeptide-3 returns nothing; the same search for semaglutide returns 5.
Cosmetic labels: "copper tripeptide-3" is the name cosmetic suppliers use for this copper complex. Several US sunscreen and skin-care labels list a "tripeptide-3" among their inactive ingredients; a name without "copper" does not identify a copper complex, and the label does not state the sequence.
Regulatory, sport: AHK-Cu is not named on the World Anti-Doping Agency's Prohibited List, but "not named" is not "permitted". Section S0 prohibits, at all times, any pharmacological substance not addressed elsewhere on the list and with no current approval by a government health authority for human therapeutic use. Athletes should put the question to their anti-doping organisation rather than read absence as clearance.
Research use: sold and handled as a research chemical only; not intended for human or veterinary use, and not approved to treat, cure or prevent any condition.
Research timeline
Dated milestones taken from the primary records: the molecule's discovery, its first registered human study, the trials that shaped the evidence and the regulatory decisions. Each entry links to the record it comes from.
A laboratory study from Seoul, the only study of AHK-Cu a PubMed search returns, reports that it lengthened human hair follicles kept alive in culture and made dermal papilla cells multiply in a dish; PubMed lists no study in animals or people since. PMID 17703734
Records checked Oct 4, 2026
Claims at a glance
The claims most often made about this compound, each with the strongest kind of evidence we found for it. The grade says what was studied, not whether the claim is true; the line beside it says what that study showed.
Regrows and thickens hairCell or tissue studies only. Human scalp follicles kept alive in a dish grew longer with it, in one 2007 study; nobody has tested it on a living scalp. PMID 17703734
Lengthens the hair growth phaseNo study found. The one study of AHK-Cu did not score hair-cycle phases, and no other study of it exists. PMID 17703734
Boosts blood supply to follicles by raising VEGFNo study found. The one study mentions VEGF only as background from earlier copper-peptide work on skin cells; it did not measure it in follicles. PMID 17703734
Works better on hair than GHK-CuNo study found. The two have never been compared: a PubMed search for AHK-Cu returns one record, the 2007 study, which had no GHK-Cu group. PubMed search, Oct 7, 2026
Firms skin and reduces wrinklesNo study found. No study has applied AHK-Cu to skin; the only PubMed record for it is a hair-follicle study in a dish. PubMed search, Oct 7, 2026
Works when injectedNo study found. No animal or person has been given AHK-Cu by any route in a published study, and how long it lasts in the body has never been measured. PubMed search, Oct 7, 2026
The reasoning behind each grade, study by study, is in this guide's Benefit & Outcome Review.
Grades checked Oct 7, 2026
A printable reference sheet with the compound's key facts, storage guidance and a vial record comes with All-Access Lifetime.
Half-life & pharmacokinetics
No half-life has been measured for AHK-Cu in people, in animals or in any published experiment. This page previously said small copper-peptide complexes are believed to be cleared within hours; that estimate had no source and is withdrawn. The only related measurement concerns GHK, not AHK: GHK occurs naturally in human plasma, saliva and urine, and declines with age (Pickart et al., Biomed Res Int 2015, PMID 26236730). Nothing about how long applied or injected AHK-Cu persists can be inferred from that.
Reported side effects & toxicology
There is no human safety data for AHK-Cu: no trial has given it to anyone, so no side-effect rate exists. What can be said comes from copper itself. Every application adds copper to whatever the body already receives from food and supplements, and copper in excess is toxic. Wilson's disease, an inherited disorder in which the body cannot clear copper, is the condition in which any added copper source matters most. Skin irritation, redness and itching are reported anecdotally with copper-peptide cosmetics generally. None of this is a characterised safety profile.
Storage & handling
Lyophilized (freeze-dried) powder: reported as stable refrigerated; longer-term storage at -20C (about 1 year) or -80C (up to ~2 years), kept away from heat, light, and moisture.
Reconstituted or in-solution serum: store refrigerated at 2-8C, protect from light, and use within roughly 28-30 days; do not refreeze.
References
Pyo HK et al., Arch Pharm Res 2007;30(7):834-9 (PMID 17703734); PubChem CID 168431292 and CID 7408502; PubMed and ClinicalTrials.gov searches run 24 September 2026 with named controls; FDA's 503A bulk-substances list (updated 14 May 2026), 503B list (updated 21 March 2025) and its page on bulk drug substances that may present significant safety risks (current as of 22 April 2026); openFDA drug-label search; the WADA Prohibited List. Educational only; not a substitute for professional or medical advice.
Evidence File
The AHK-Cu Evidence File: One Paper, Nineteen Years, and No Second Study
The entire published record of AHK-Cu is one laboratory paper from 2007. PubMed returns it for every spelling of the name, and returns nothing for the cosmetic name copper tripeptide-3. A search on the three-amino-acid sequence returns 29 records, and reading them shows why the count misleads: almost all concern the first four residues of human albumin and how they bind copper. The one human scalp study of a "copper tripeptide" used a different peptide, GHK-Cu, in a multi-ingredient serum. ClinicalTrials.gov lists nothing. This file sets out exactly what the one study measured, what it could not, and what the other records are.
1 PubMed record for AHK-Cu, under every spelling
29 records for the sequence Ala-His-Lys — none on AHK-Cu, hair or skin
0 animal studies, 0 human studies, 0 registered trials
203 records for GHK-Cu under the same search design
How large this literature is: one paper, found under every name
What the one study measured, and what it did not
The 29 sequence records and the 16 "tripeptide-copper" records, sorted
The registries, the human hair studies that are about something else, and what would change the picture
4 more sections in the Evidence File for AHK-Cu
Unlock the Evidence File, Sourcing File and Benefit & Outcome Review for AHK-Cu for $14 — or every compound in the library, plus the printable reference sheets, for $99.
The sections above this one stay free to read without an account.
Sourcing File
The AHK-Cu Sourcing File: Two Registry Records, a Copper Signature, and Six Sequences With the Same Mass
AHK-Cu is two things that must both be verified: a three-amino-acid peptide and the copper ion it holds. They sit in PubChem as separate records with different masses, and a certificate that reports only one of them has not described the product. Copper leaves a distinctive two-peak signature in a mass spectrum, which makes the complex easier to confirm than most peptides. The peptide is harder: the same three amino acids in any of six orders weigh exactly the same, and PubChem lists eight records with AHK's atoms and bonds, five of them built from mirror-image residues. This file turns those facts into questions for a certificate of analysis.
2 PubChem records: the peptide at 354.41 and the copper complex at 451.39
14.1% of the complex's weight is copper, 7.9% chloride
6 orders of A, H and K, all 354.20 daltons
8 PubChem records share AHK's connectivity, 5 with D-residues
Identity numbers: which record a certificate is describing
The copper signature, and the copper that is not bound
Sequence and mirror-image variants: what a mass cannot tell apart
What to ask a supplier, in order
4 more sections in the Sourcing File for AHK-Cu
Unlock the Evidence File, Sourcing File and Benefit & Outcome Review for AHK-Cu for $14 — or every compound in the library, plus the printable reference sheets, for $99.
The sections above this one stay free to read without an account.
Benefit & Outcome Review
The AHK-Cu Benefit & Outcome Review: Every Claim Traced to One Dish Study or to a Different Peptide
AHK-Cu is sold for hair regrowth, thicker hair, a longer growth phase, and as a more hair-specific alternative to GHK-Cu, applied to the scalp or injected. Trace each claim and it leads to one of two places: a 2007 laboratory study of hair follicles and cells in a dish, or research on GHK-Cu. No study has put AHK-Cu on a living scalp, injected it into an animal or a person, or compared it with anything. The human hair studies that circulate used GHK-Cu, mixed with other actives. This review takes the claims one at a time and says what, if anything, stands behind each.
0 studies measuring hair count, density or shedding after AHK-Cu
0 head-to-head comparisons with GHK-Cu, minoxidil or anything else
0 people or animals ever given AHK-Cu in a published study
1 laboratory study behind every hair claim
Hair growth: what "stimulated follicle elongation" can and cannot carry
A longer growth phase, VEGF and the other mechanisms attributed to it
"More hair-specific than GHK-Cu": a comparison nobody has run
Injected, on skin, and safety: nothing measured in a living body
4 more sections in the Benefit & Outcome Review for AHK-Cu
Unlock the Evidence File, Sourcing File and Benefit & Outcome Review for AHK-Cu for $14 — or every compound in the library, plus the printable reference sheets, for $99.
Quick answers about guide scope, access, and educational use context.
What is AHK-Cu?
AHK-Cu is the tripeptide alanine-histidine-lysine bound to a copper ion, sold in cosmetics as copper tripeptide-3. In PubChem the copper complex is CID 168431292 (CAS 682809-81-0) and the peptide without copper is CID 7408502 (CAS 126828-32-8). It is not an approved medicine anywhere.
What does the research on AHK-Cu actually show?
One laboratory study (Pyo et al., Arch Pharm Res 2007, PMID 17703734) found that AHK-Cu at picomolar to nanomolar concentrations lengthened human hair follicles kept in culture and made dermal papilla cells multiply faster, with less molecular evidence of cell death. That is the entire published evidence. No study in animals or people exists.
Does AHK-Cu regrow hair?
That has never been tested. The one study used isolated follicles and cells in a dish; no one has measured hair count, density or shedding after applying AHK-Cu to a living scalp. Regrowth claims are marketing and anecdote, not study results.
Is AHK-Cu applied to the skin or injected?
Cosmetic products apply it to the skin, and some community sources describe injecting it. Neither route has been studied: no trial, animal study or pharmacokinetic study of AHK-Cu by any route has been published, and it is not approved for injection anywhere.
How is AHK-Cu different from GHK-Cu?
They differ by one amino acid: alanine instead of glycine at the start. GHK-Cu occurs naturally in human plasma and has a substantial literature — 212 PubMed records on 24 September 2026, against one for AHK-Cu — and FDA has taken positions on it: injectable GHK-Cu is on its safety-risk page, and non-injectable GHK-Cu is under evaluation for compounding. AHK-Cu has no FDA position at all. The claim that AHK-Cu is more hair-specific than GHK-Cu has never been tested head to head.
Where does the withdrawn “biphasic” dose-response claim come from?
Not in the published evidence. The one study reports stimulation across every concentration it tested, 10⁻¹² to 10⁻⁹ M, and tested nothing higher. This page previously repeated the biphasic claim; we could not trace it to any publication, and it is withdrawn.
What is the half-life of AHK-Cu?
It has never been measured, in people or in animals. The "cleared within hours" estimate this page used to give had no source and is withdrawn.
Is AHK-Cu banned in sport?
It is not named on the WADA Prohibited List, but section S0 prohibits any pharmacological substance with no current approval for human therapeutic use, which describes AHK-Cu. Athletes should ask their anti-doping organisation rather than treat absence from the list as permission.
Compliance and trust notes
Educational content only; no personalized health or outcome claims.
No personalized use recommendation outputs.
Use this material for general learning and research-context literacy.
A certificate of analysis (COA) is a laboratory’s report on one sample of one batch. The single most useful thing to know about it is that purity and identity are two separate results that fail in different ways. A high purity figure says the sample was mostly one substance; it does not say that substance was AHK-Cu. Identity — normally a mass-spectrometry result matching the expected molecular weight — is what establishes what the material actually is, and a certificate reporting purity alone has not answered that question.
Two further limits are worth holding onto. Mass per vial is its own test: a vial can be 99% pure and still contain less material than the label claims. And sterility, endotoxin, heavy metals and residual solvent screening are separately commissioned tests, usually priced individually — so a “third-party tested” badge asserts none of them unless the certificate names them. Check that the batch or lot number on the document matches the vial in front of you; an unmatched certificate describes someone else’s material.
Specific to AHK-Cu
As with GHK-Cu, a purity figure for the AHK peptide does not by itself establish the copper component of the complex. AHK-Cu is also predominantly a topical research material, so sterility and endotoxin testing — usually priced separately from purity — carry different weight here than for an injectable.
Medibact does not test, endorse or resell peptides, and publishes no rating of any laboratory. How to read a peptide certificate of analysis walks through the document section by section, and what each COA field establishes covers the field-by-field detail and the laboratories that publish their methods.
You’ll need bacteriostatic water
The diluent for reconstituting AHK-Cu
Reconstitution is volume arithmetic — it assumes a lyophilized vial is dissolved in bacteriostatic water, which is sterile water preserved with 0.9% benzyl alcohol. The preservative is what allows a vial to be entered more than once; plain sterile water carries none and is single-entry by design. Medibact supplies USP-grade Bacteriostatic Water for Injection in a 30 mL multi-dose vial, made in the United States and shipped from the United States, for research use only. One 30 mL vial covers 30 reconstitutions at 1 mL each, 15 at 2 mL, or 10 at 3 mL — division only, not a dosing recommendation.
Educational use only — not medical advice. This guide summarizes information reported in published research and community practice for educational purposes. It is not medical advice and not a recommendation to use any compound. Any doses, schedules, or combinations shown are examples of what has been reported, not instructions for you. Many peptides described here are research compounds that are not FDA-approved for the uses discussed and may be investigational or restricted. Effects, risks, and legal status vary; individual needs and results vary. Consult a qualified, licensed healthcare professional before making any decision. Do not use this content to diagnose, treat, or dose yourself.
