AHK-Cu_Dosage, benefits & legal status
Also known as AHK copper, Ala-His-Lys copper, copper tripeptide-2
GHK-Cu's less-studied cousin, sold mainly for hair.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is AHK-Cu?
Plain language first. The technical label stays, but it never stands alone.Overview
It is the same idea as GHK-Cu with far less research behind it.
AHK-Cu is a copper peptide, the same family as GHK-Cu. It is three amino acids holding a copper atom, and copper is genuinely needed for building skin and blood vessels. It is sold mostly for hair rather than skin.
What it's used for
Applied to the scalp or skin, mostly marketed for hair thickness.
How does AHK-Cu work?
What it does in the body, and where.Copper peptides work as a delivery system. The peptide part holds the copper and carries it where a plain copper salt could not go.
- 01Three amino acids hold a copper atomThat bond is the whole point. Loose copper is irritating and does not absorb well.
- 02Copper is needed to build skin and blood vesselsSeveral enzymes involved in making collagen and elastin will not work without it.
- 03The hair claim is the thinnest partMost of what is written about AHK-Cu leans on studies of GHK-Cu, which is a different molecule with a different first amino acid.
Where this compound is thought to act.
What else is it used for?
Each use below carries its own evidence level. Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
- Hair thickness and follicle support, which is the main marketing claimEarly research
- Skin repair and collagen, borrowed from GHK-Cu research rather than its ownResearch only
How much, and do you cycle it?
The range, and whether you take breaks.Topical serum, per product, daily. Applied daily, with no established courseCommunity practice
Treated like a skincare ingredient rather than a course of treatment. No study has tested a duration.
How long does it stay in the body?
The half-life, and where the figure comes from.Not measured, and not the right questionNo figure
This is a topical cosmetic ingredient. A blood half-life measures how fast something leaves the bloodstream, and these are not intended to reach it in meaningful amounts. What matters for a topical is how much penetrates the skin and how long it stays in the tissue, which is a different measurement and one that is rarely published.
You can compare this against the whole library to see where it sits.
What does it cost?
Typical dose and cost, in plain numbers.AHK-Cu is not injected
It is taken on the skin (topical). Applied as a topical product. There is no injected dose and no tested strength.
AHK-Cu starts at $47.99 across 8 vendors, typically $0.48 – $1.01 per mg.
8 listings, last read Aug 24, 2026. Shipping and card fees are not included.
How do you store it?
Before mixing, and after.Room temperature, out of light. Cap it tight after each use.
AHK-Cu ships as a cream, gel, or serum. Keep it at room temperature away from sun and heat unless the label says otherwise. Refrigerating an emulsion can split the texture. Watch for color, smell, or separation changes and stop using it if any appear.
What are the side effects and cautions?
Known cautions and warnings for this compound.Copper peptides and strong acids or vitamin C do not sit well together in the same routine, because the acid can pull the copper off the peptide. Use them at different times of day. Also check what you are buying: a lot of what is marketed as AHK-Cu is sold on the strength of GHK-Cu research, and they are different molecules.
Who should avoid it
- Known copper allergy
- Wilson's disease, a condition where copper builds up in the body
- Broken or badly irritated skin
Stop and get help
- A spreading rash or burning where it was applied
- Signs of an allergic reaction
Common effects
- Mild stinging or redness when first used
- A blue-green tint to the product, which is normal for copper
- Beyond that, little is documented, because little has been published
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is AHK-Cu approved?
And where the numbers on this page come from.Not as a medicine. AHK-Cu is sold without a prescription as a supplement or cosmetic ingredient, which is a different thing from being approved as a drug.
- Approval statusOTC / supplement
- RouteOn the skin (topical)
- CheckedAugust 2026
What has happened recently
We have not yet written a full regulatory note for this compound. The status above is current as of the date shown.
You can compare this against the whole library, or read how to check a seller.
- DoseFrom product labeling and published use.
- Vial sizeFrom what vendors typically list; not a recommendation.
- Reviewed14 August 2026
What else is like AHK-Cu?
Others in Skin and cosmetic, side by side.If you're weighing AHK-Cu, it's worth reading Acetyl Tetrapeptide-3, Biotinoyl Tripeptide-1, and Palmitoyl Tetrapeptide-7 in the same class.
GHK-Cu's less-studied cousin, sold mainly for hair.
- Dose
- Topical serum, per product
- How often
- Daily
A hair peptide sold for thinning, with evidence that mostly belongs to a combination product.
- Dose
- Serum or scalp treatment, 0.1 to 5%
- How often
- Daily
GHK with a biotin tail, sold for hair and lashes rather than skin.
- Dose
- Serum, 2 to 6 ppm typical in a finished product
- How often
- Daily
An anti-inflammatory skin peptide, almost always sold alongside Matrixyl.
- Dose
- Serum or cream, typically 200 mg of active per formulation batch
- How often
- Daily
10What these words mean
Show glossary +
What these words mean
- 503A and 503B
- The two kinds of compounding pharmacy in US law. A 503A pharmacy prepares medicine for one named patient. A 503B outsourcing facility makes larger batches under stricter manufacturing rules.
- Agonist
- Something that switches a receptor on. The opposite is an antagonist. It blocks the receptor instead.
- Amino acid
- The building blocks that link together in a chain to make a peptide or a protein. The order they sit in is what makes one peptide different from another.
- Amylin
- A hormone released alongside insulin that slows the stomach emptying and reduces appetite. Several weight loss compounds copy it.
- Analog
- A compound built to copy a natural one with small deliberate changes, usually so it lasts longer or holds onto its target more tightly.
- Animal study
- Research done in rats, mice or other animals. Most findings do not repeat in people, so an animal result is a reason to keep looking. It is not a reason to act.
- Antibody
- A large immune protein, far bigger than a peptide, engineered to lock onto one specific target. These are made by drug companies and are not sold as research powders.
- Bacteriostatic water
- Sterile water with a tiny amount of preservative, used to mix powdered peptides.
- Banned in drug-tested sport
- Prohibited by the World Anti-Doping Agency (WADA); using it can disqualify a competing athlete.
- Bioavailability
- How much of a dose actually reaches your bloodstream. Most peptides survive stomach acid badly, so most of them are injected instead of swallowed.
- Bioregulator
- Very short peptides from a Russian research tradition, usually two to four amino acids long, sold for supporting a specific organ. Human evidence is thin and most of it is published in Russian.
- Blend
- One vial holding more than one compound, mixed together by the seller. Working out a dose means working out each ingredient separately, because they are rarely present in equal amounts.
- Boxed warning
- The most serious warning the FDA puts on a drug label, printed inside a black border. It flags a risk considered severe enough to sit above everything else on the label.
- Bulks list
- The FDA's list of ingredients that compounding pharmacies are allowed to use. A substance can sit under review on it for years without anything being decided either way.
- Certificate of analysis (COA)
- A lab report on a batch of product. It only means something if it names the batch you actually received, comes from an independent lab, and can be checked with that lab.
- Clinical trial
- A study that gives a treatment to people under a written plan and measures what happens. It is the only kind of evidence that can show something works in humans.
- Compounding
- A licensed pharmacy preparing a medicine to order. Being allowed to compound something is not the same as the FDA approving it, and the two get mixed up constantly.
- Concentration
- How strong the mixed peptide is, in milligrams per milliliter (mg/mL). More water makes it weaker; less water makes it stronger.
- Cycle
- A stretch of time using a compound followed by a break. Most cycling patterns come from community practice. Very few have been tested.
- DAC
- Short for Drug Affinity Complex. An attachment added to a peptide so it grabs onto a blood protein and stays in the body for days instead of minutes.
- Dead space
- The small amount of liquid left sitting inside the needle and hub after you inject. On very small doses it can be a real share of what you meant to take.
- Dilute
- Adding more liquid to make a mix weaker. The amount of peptide in the vial does not change. It is just spread through more water, so each draw is bigger.
- Endpoint
- The result a trial said in advance that it would measure. A study can be reported as positive and still have missed the endpoint it set out to hit.
- FDA approved
- Reviewed by the FDA and cleared for a specific use, in a specific form, at a specific dose. Approval for one use is not approval for another, and approval in another country is not approval here.
- Fragment
- A short piece cut out of a larger natural protein. A fragment can behave very differently from the whole protein it came from, so evidence about one does not transfer to the other.
- Ghrelin
- The hunger hormone. Some growth hormone compounds work by copying it, so they can make you noticeably hungrier.
- GHRH
- A natural signal telling the pituitary gland to release growth hormone. Several compounds copy it.
- GHRP
- A second, separate signal that also triggers growth hormone release, through a different door than GHRH. This is why the two types are often used together.
- GLP-1
- A natural gut hormone that lowers appetite and blood sugar. Drugs that copy it, like semaglutide, are used for weight loss.
- Growth hormone secretagogue
- A compound that nudges your body to release more of its own growth hormone, rather than injecting the hormone itself.
- Half-life
- How long a compound stays active in your body. A longer half-life means you inject less often.
- HPLC
- A lab method that separates out everything in a sample so the amounts can be measured. It shows how much of the main ingredient is there. It does not confirm that the main ingredient is the right molecule.
- In vitro
- Done in a dish or a test tube, on cells outside a living body. It is the earliest kind of evidence there is.
- Injection site
- The spot on the body where you inject. Moving it around gives the skin and fat underneath time to recover between doses.
- Intramuscular (IM)
- An injection into a muscle, using a longer needle.
- Intravenous (IV)
- An injection into a vein. It needs training and equipment and is not something to do at home.
- Investigational
- Still being tested in clinical trials and not yet approved or legally sold for general use.
- Lyophilized
- Freeze-dried into a powder so it keeps longer. That is the white cake or dust in the bottom of an unmixed vial.
- Mass spectrometry
- A lab method that weighs molecules to confirm what they are. HPLC answers how much is in the sample. This answers what it is.
- mcg and mg
- Units of dose. 1 milligram (mg) equals 1,000 micrograms (mcg).
- Myostatin
- A natural brake on muscle growth. Several compounds are built to block it, though human results have been far smaller than the animal work suggested.
- Off-label
- A doctor prescribing an approved drug for something other than its approved use. This is legal and common, and it is different from a compound having no approval at all.
- Orphan drug designation
- A status given to treatments for rare conditions to make them worth developing. It is an incentive, not an approval, and a compound can hold it while being approved for nothing.
- PCAC
- The FDA advisory committee that reviews compounding ingredients. It recommends. It does not approve, and the FDA does not have to follow what it says.
- Peer review
- Other scientists checking a paper before a journal publishes it. It filters out some bad work. It does not make a finding true.
- Peptide vs small molecule
- A peptide is a short chain of amino acids. A few items here (like MK-677 or methylene blue) are small molecules, not true peptides, but people use them the same way.
- Placebo
- A dummy treatment given for comparison. Without one it is very hard to tell a real effect apart from expectation and time passing.
- Purity
- The share of a sample that is the intended compound, usually given as a percentage. A high purity number on the wrong molecule is still the wrong molecule.
- Randomized
- Deciding by chance who gets which treatment, so the two groups are comparable. Studies that skip this are much easier to read the wrong way.
- Receptor
- A docking point on a cell that a compound attaches to. If a cell has no matching receptor, the compound does nothing to it.
- Reconstitution
- Mixing a powdered peptide with liquid (bacteriostatic water) so it can be drawn into a syringe.
- Research only
- No approved dose or use in people. Sold for research and not reviewed by the FDA for safety or quality.
- Stack
- Using more than one compound at the same time. Almost no combinations have been tested together in people, so a stack is usually built on guesswork.
- Sterile water
- Water with nothing added to stop bacteria growing. It works for a single dose, but a vial mixed with it should not be kept and used again.
- Subcutaneous
- An injection just under the skin, into the fat layer, usually with a short, thin insulin needle.
- Titrate
- Starting at a low dose and increasing it slowly over time so your body adjusts and side effects stay mild.
- Trial phases
- The stages of human testing. Phase 1 checks safety in a small group, phase 2 looks for an effect, and phase 3 tests it against a comparison in a large group.
- Units (on the syringe)
- The marks on an insulin syringe. 100 units equals 1 mL. They measure how much liquid you draw, not the dose in milligrams.
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- Why Does My Peptide Injection Itch or Welt
Injection-site irritation, a histamine reaction, or a true allergy, and how to tell them apart.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Last reviewed 14 August 2026
Peptide Decoding is published by Decoded Sciences LLC. We take no payment from vendors for coverage, inclusion or ranking, and our affiliate relationships are disclosed in full.