GHK-Cu and AHK-Cu are one amino acid apart, and that single substitution changes which research question each one is better suited to. If you are deciding between them — or wondering why you would ever need both — this is the short version.
Quick comparison
| GHK-Cu | AHK-Cu | |
|---|---|---|
| Sequence | Gly-His-Lys | Ala-His-Lys |
| Difference | glycine at position 1 | alanine at position 1 |
| Most studied for | extracellular matrix, collagen synthesis, wound models | follicle and dermal papilla biology |
| Typical research setting | dermal and matrix work | ex vivo human follicle studies |
| Price | 50 mg $35 ($0.70/mg) · 100 mg $60 ($0.60/mg) | 100 mg $50 ($0.50/mg) |
| Best fit | skin matrix, broad copper-peptide work | scalp and follicle work |
One residue, different literature
Both are copper tripeptides: a three-amino-acid chain with a copper ion bound at the histidine. GHK begins with glycine. AHK begins with alanine. The metal binding, the charge behaviour and the way they are handled in the lab are close enough that the difference is easy to miss — and far enough apart that the published work diverges.
GHK-Cu has the broader literature. It appears across extracellular matrix research: fibroblast activity, collagen synthesis, matrix metalloproteinase regulation, and wound-healing models. If the research question is about the dermal matrix in general, GHK-Cu is where the citations are. The full pathway overview covers that in detail.
AHK-Cu has a narrower and more specific literature. It is the peptide in the foundational follicle patent — US6017888A, “Stimulation of hair growth by peptide copper complexes” — and it appears in ex vivo human follicle work, where the measured endpoints are follicle elongation, shaft calibre and anagen extension. The AHK-Cu research entry walks through those studies.
What the evidence actually supports
Worth being precise, because the marketing in this category is not. The GHK-Cu skin literature is largely cell culture and wound-model work; the AHK-Cu follicle literature is largely ex vivo — human follicles maintained outside the body, which is a stronger model than a cell line and still not a clinical trial. Neither compound has the kind of controlled human outcome data that would justify a claim about a person’s hair or skin.
That is not a weakness of the compounds. It is what the evidence is, and knowing the difference is the reason to read the studies rather than the reviews.
Which one for which question
If the research question is the dermal matrix
GHK-Cu. Broader literature, more replicated endpoints, and it is the copper peptide most of the matrix research is built on. It is also the practical first purchase, because it covers both skin and follicle work at a lower entry price. The skin-matrix entry covers that research in detail.
If the research question is the follicle specifically
AHK-Cu. The patent and the ex vivo work are both about follicle biology, and the endpoints — elongation, calibre, anagen extension — are follicle-specific in a way the general matrix literature is not.
If you want to study both
They are not substitutes, and combining them in a single research design is a legitimate question rather than a marketing one. Two vials, one carrier, and separate labels is the minimum: if you mix them into the same formulation you can no longer attribute the result to either.
Handling: identical, mostly
Both are water-soluble copper peptides supplied as lyophilised powder. Both reconstitute with bacteriostatic water, both foam if shaken, both are blue in solution and both turn green or brown on oxidation. The dilution arithmetic is the same: 10 mg/ml stock, then dilute into a carrier.
The practical difference is vial size. AHK-Cu is supplied at 100 mg, which makes 100 ml at 0.1% — more than localized work usually needs. GHK-Cu comes in 50 mg and 100 mg, so you can size the batch to the job. The full preparation method applies to both.
Cost per milligram
Published openly, because most listings hide it:
- GHK-Cu 50 mg — $35 — $0.70/mg
- GHK-Cu 100 mg — $60 — $0.60/mg
- AHK-Cu 100 mg — $50 — $0.50/mg
AHK-Cu is the cheaper peptide per milligram; GHK-Cu is the cheaper first purchase. If you are running a dual design, the 100 mg GHK-Cu tier is the better rate.
Frequently asked questions
Is AHK-Cu just a stronger GHK-Cu?
No. They are different sequences with different literatures. “Stronger” is not a meaningful comparison for compounds studied in different models with different endpoints.
Can I substitute one for the other in a protocol?
Only if the research question is about copper peptides generally rather than a specific tissue. If the endpoints are follicle-specific, the AHK-Cu literature is the relevant one; if they are matrix-specific, GHK-Cu is.
Do they need different diluents?
No. Both reconstitute in bacteriostatic water. Neither needs an acid adjustment at normal working concentrations.
Which should I buy first?
GHK-Cu at 50 mg if you are starting out — it covers more ground for less money and the method is documented end to end. AHK-Cu if the follicle is the question.
Both, priced openly. GHK-Cu 50 mg $35 ($0.70/mg) · 100 mg $60 ($0.60/mg). AHK-Cu 100 mg $50 ($0.50/mg). Certificate of analysis available for the batch, Canadian stock, orders before 2 PM EST dispatch the same day.
For laboratory research only. Not for human or veterinary use.
Free resource
New to peptide research?
The free 51-page guide covers 12 compound profiles, reconstitution math, COA reading and storage — without the hype.
Get the free guide →Or start with the 2-page checklist
2 comments