How is it different from GHK-Cu?

One amino acid, and a great deal of research. GHK-Cu has decades of dermatological literature; AHK-Cu has cell-culture work focused on hair follicles. Evidence for one is not evidence for the other.

No controlled human trial has shown that. The cell-culture findings are about dermal papilla cells in a dish, which is several steps away from hair on a head.

Skin & hair

AHK-Cu

Copper tripeptide-3 · Ala-His-Lys copper

PreclinicalReviewed 18 Aug 2026

AHK-Cu is a copper-binding tripeptide, closely related to GHK-Cu and distinguished mainly by being studied far less. Where GHK-Cu has decades of dermatological research behind it, AHK-Cu has a much thinner literature and a narrower focus on hair.

Its research interest is in the hair follicle: cell-culture work reports increased dermal papilla cell proliferation and prolonged growth phase, which is the mechanism a hair-loss treatment would need. It appears in cosmetic hair serums on that basis.

The honest caution is about citation drift. Search for AHK-Cu and much of what comes back is copper-peptide research generally, most of it GHK-Cu. They are different molecules, and evidence does not transfer between them because both happen to carry copper.

How it works

AHK-Cu is a tripeptide that binds copper, delivering it into tissue. Copper is a cofactor for enzymes involved in building collagen and elastin, which is the general basis for copper peptides in skin research.

In hair specifically, cell-culture work reports that it stimulates dermal papilla cells, the cells at the base of the follicle that govern growth, and extends the anagen or growth phase.

As with every topical peptide, penetration is the limiting factor. Whether a molecule applied to the scalp reaches the follicle base in useful quantity is the question the cosmetic literature is worst at answering.

Quick reference

Commonly described dose: 1 mg–5 mg
How often: Applied to the scalp once or twice daily
Route: Topical
Where: Scalp
Timing: Once or twice daily to clean, dry scalp.
Storage once mixed: Refrigerated, 14 days

These describe what sources report, not what you should do. Full detail and provenance in the dosing section below.

Price index

Per-milligram pricing across vendors arrives with the directory. We are recording prices now so the history exists when the page ships.

Vocabulary on this page

Bioavailability: How much of an administered dose actually reaches the bloodstream. Injection is close to complete; swallowing a peptide is usually close to nothing.
Concentration: How much peptide there is in each millilitre of solution, once the vial has been reconstituted.
Reconstitution: Adding liquid to a freeze-dried peptide powder to turn it into a solution that can be drawn into a syringe.
Peptide: A short chain of amino acids: the same building blocks as a protein, in a chain short enough to behave differently.

The whole glossary →

Regulatory status — United States

Sold as a cosmetic ingredient, not a drug. Cosmetics are not assessed for efficacy before sale, and no medicine containing it is approved for hair loss anywhere.

Last reviewed 18 Aug 2026. Regulatory positions in this category change frequently; we date this line so you can see how current it is.

What it is studied for

Each entry states the evidence behind it. We do not rank indications by effectiveness — for most compounds here, that would be a claim nobody can support.

Hair growth

Published review

The use it is sold for.

EvidenceCell-culture work reports dermal papilla cell proliferation and extended growth phase. No controlled human trial establishes an effect on hair.

Skin repair

Published review

By extension from copper peptides generally.

EvidenceMost of the skin research on copper peptides is GHK-Cu, not this molecule. Evidence does not transfer between them.

Identity and clearance

Molecule

Class: Copper-binding tripeptide
Length: 3 amino acids

Sequence

Ala-His-Lys

Distinct from GHK-Cu (Gly-His-Lys) by one residue, and studied far less.

Dose protocols reported in sources

Displayed for reference only. Every row says where it came from, and a trial protocol and a community convention are not the same kind of information. None of this is fed into the calculator, and none of it is a recommendation.

Dose protocols reported in sources, with the source of each.
Goal	Dose	Frequency	Route	Units	Source	Start this protocol
Concentration used in cosmetic formulations	1 mg – 5 mg	Applied to the scalp once or twice daily	TopicalSerums typically contain a fraction of a per cent. The figures here express the peptide content of a typical application, not an injected dose. For a topical, the vehicle matters more than the number does.	—	Manufacturer	Start this

Start this copies a row into a protocol of your own, which you can then edit. Where a source gave a dose range or an ambiguous frequency, those fields arrive empty — we will not pick a number on your behalf.

Safety

Reported effects

Skin irritationManufacturer
Uncommon
Temporary blue-green stainingManufacturer
Reported
The copper. Cosmetic rather than harmful.
Systemic effectsPublished review
Not expected from topical use
The same skin barrier that limits penetration limits absorption.

When to stop

Persistent redness, itching or burning on the scalp.
Any rash spreading beyond the application area.
Signs the product has spoiled: separation, colour change or smell.

Interactions and situations that need care

Broken or irritated scalpUse caution
Applying anything to compromised skin bypasses the barrier that limits both absorption and irritation, which changes the risk from negligible to unpredictable.
Wilson's disease or any copper metabolism disorderAvoid
Deliberately delivering copper into tissue in someone whose body cannot regulate copper is the one genuinely serious contraindication for any copper peptide.
Injecting itAvoid
The research is topical and the product is a cosmetic. Injecting a copper complex has no supporting evidence and introduces a metal-loading question that topical use does not.
Mixing your own from raw powderUse caution
A finished cosmetic carries a preservative system for a reason. A home mix has none — grows bacteria within weeks — and goes on your scalp.

What to expect

HonestlyThere is no human efficacy data for this compound, so there is no evidence-based timeline to give. Any site publishing a week-by-week schedule of expected effects has invented it.

The evidence is cell culture. No controlled human trial establishes an effect on hair.
Most copper-peptide research people cite is GHK-Cu, a different molecule. It does not transfer.
It is a cosmetic, not a medicine, and cosmetics are not assessed for efficacy before sale.
Copper peptides are blue. If a solution sold as one is not, ask why.
Penetration is the limiting factor for any topical peptide, and the formulation matters more than the percentage.

Storage and handling

Freeze-dried powder: Finished serums at room temperature, out of direct sunlight. Raw peptide powder is best refrigerated.
After mixing: A finished cosmetic has a preservative system and lasts months. A serum mixed at home has none and will grow bacteria. That is the practical risk with any topical peptide.

Printable one-pager How to reconstitute a vial, step by step

With other peptides

GHK-Cucaution
Both are copper-delivering tripeptides. Using both means delivering copper by two routes at once, and GHK-Cu is the one with the actual research behind it.

Check this against a whole stack

Checking your vial

Research chemicals carry no manufacturing standard, so what the vial looks like is often the only quality signal available before you use it. More on assessing quality and COAs.

Blue solution
Copper peptides are blue. A colourless copper-peptide solution is a reason to ask what is in it.
Separation, colour change or smell in a finished serum
The preservative system has failed. Discard it.

Questions

How is it different from GHK-Cu?: One amino acid, and a great deal of research. GHK-Cu has decades of dermatological literature; AHK-Cu has cell-culture work focused on hair follicles. Evidence for one is not evidence for the other.
Does it regrow hair?: No controlled human trial has shown that. The cell-culture findings are about dermal papilla cells in a dish, which is several steps away from hair on a head.

References

AHK-Cu and dermal papilla cell proliferation: cell culture findings
Dermatology and cosmetic science literature, 2007 · Cell culture studies
In vitro
Reported increased dermal papilla cell proliferation and extended anagen phase in culture. No controlled human trial has established an effect on hair growth.
Commonly reported community protocols
Bioalmanac editorial summary of public community sources, 2026 · Not a study
Records dose and route patterns described in public discussion. Carries no evidential weight about safety or effect.

AHK-Cu compared with

GHK-Cu vs AHK-Cu

Two copper peptides sold for different tissue. Both carry copper, and that is why running them together is a question, not a default.

Related compounds

GHK-Cu

A naturally occurring copper-binding tripeptide with a long history in topical skincare research. Injected use is not what the research studied.

SNAP-8

An extended version of Argireline, sold on the same needle-free-Botox premise. Longer peptide, same penetration problem, and less independent evidence.

Melanotan II

A melanocortin agonist that darkens skin by stimulating melanin production. Carries the most serious dermatological concern of anything on this site.

Afamelanotide

The approved member of the melanotan family. Same idea as melanotan II, taken through a full regulatory process, and the contrast between them is instructive.

Keep this page honest

If something here is wrong, out of date, or missing a source, tell us and we will fix it and say that we did.

Suggest a correction

This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on Bioalmanac is medical advice. No clinician reviews these pages.

Page last updated 18 Aug 2026