AHK-Cu
Also known as Copper tripeptide AHK, Alanyl-histidyl-lysine copper, AHK copper complex
AHK-Cu is a copper-bound tripeptide closely related to GHK-Cu that is used mainly for hair growth. It is applied topically to the scalp, often with microneedling, and has cell and small human study evidence for stimulating hair follicle cells.
Reviewed by the amino101 editorial team. , first published .
Quick start
What people commonly do. Not a prescription.- Typical dose
- 0.5 to 1 mg applied to the scalp (roughly 1 percent solution); some inject 0.5 to 1 mg subcutaneously, with no data
- How often
- once daily
- Where
- Topical, on clean dry scalp over thinning areas; injection is not a typical route
- Timing
- evening after washing, so it sits on the scalp overnight; microneedling once weekly before application
- Effects timeline
- reduced shedding 6 to 8 weeks, visible thickening 3 to 6 months
- Storage
- fridge 2 to 8 C once mixed, use within 4 to 6 weeks; the solution should stay blue
- Cycle length
- ongoing; judge results at 3 to 6 months
- Break between
- none needed for topical use; stop if there is no change after 6 months
Overview
AHK-Cu is a synthetic tripeptide of alanine, histidine and lysine bound to a copper ion. It was developed as a variation on the naturally occurring GHK-Cu, swapping the first amino acid to see whether the copper-binding peptide family could be tuned toward specific effects. Where GHK-Cu is used broadly for skin, AHK-Cu found its niche in hair research after cell studies showed it stimulated the dermal papilla cells at the base of hair follicles.
The evidence is mostly laboratory work. In cultured human dermal papilla cells, AHK-Cu increased cell proliferation, reduced apoptosis and upregulated VEGF, the growth factor that supplies follicles with blood. It also inhibited the enzyme that converts testosterone to DHT in some studies, which would be relevant to pattern hair loss. A small Korean clinical study of a topical AHK-Cu solution reported increased hair count and thickness over several months.
Beyond hair, AHK-Cu shares the collagen-stimulating and antioxidant properties of GHK-Cu and is included in some anti-aging skin serums, though it has far less skin-specific data than its better known relative. There are no injectable studies and injection is not a typical route. It is sold as a lyophilized powder for reconstitution into topical solutions and as a ready-made serum ingredient. Most people who use it are treating early to moderate thinning and combine it with established treatments rather than relying on it alone.
How it works
AHK-Cu delivers copper to the dermal papilla, the cluster of specialized cells at the base of each hair follicle that controls the hair growth cycle. In those cells it raises VEGF expression, which increases blood supply to the follicle, and it activates survival signaling that reduces cell death. It also appears to lower the activity of 5-alpha reductase, the enzyme that makes DHT, the hormone most responsible for follicle shrinkage in pattern hair loss. The copper component supports lysyl oxidase and other enzymes involved in extracellular matrix building, which strengthens the tissue around the follicle. These effects together are meant to prolong the growth phase and reverse miniaturization.
Where the research stands
Pattern hair lossEmerging
- Hair count and thickness. One small clinical study of topical AHK-Cu in men with pattern hair loss reported more and thicker hairs over several months, without a large control group.
- Dermal papilla stimulation. Cell culture studies show more proliferation, less cell death and higher VEGF in the cells that feed the follicle.
- DHT reduction at the follicle. In vitro inhibition of 5-alpha reductase only; no human hormone data.
Skin support and collagenWeak or mixed
- Anti-aging serums. Assumed to share GHK-Cu collagen effects because of the near identical structure, but AHK-Cu has almost no skin-specific data of its own.
- in vitroStimulated proliferation and reduced apoptosis of human dermal papilla cells in culture.
- in vitroIncreased VEGF expression and decreased TGF-beta1 in dermal papilla cells, both favoring hair growth.
- in vitroInhibited 5-alpha reductase activity in hair follicle cells, reducing DHT production.
- human pilotTopical AHK-Cu increased hair count and hair thickness in a small clinical study of men with pattern hair loss.
Rodent and in vitro mean no human data for that finding. Human pilot means small, often uncontrolled. Human RCT means randomized and controlled. Clinical means an approved drug with regulatory data.
Levels over time
Modeled from the half-life. Illustrative, not measured.A half-life of 45 min against dosing every 24 h means each dose has cleared before the next. Nothing stacks; you start from zero every time, and the tissue effect is what carries over.
Because it acts locally at the follicle, daily reapplication matters more than any blood level, and results depend on the hair cycle rather than the pharmacokinetics of the peptide.
AHK-Cu dosage and protocols
There is no cycling in the usual sense. Hair treatments are used continuously because the follicle cycle is slow and gains reverse when the stimulus stops. Most people commit to daily use for at least 6 months before deciding whether it is doing anything.
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Thinning, topical solution | 0.5 to 1 mg (about 1 percent solution, a few drops per area) | once daily | Topical on scalp |
| Thinning with microneedling | 0.5 to 1 mg | once daily, microneedle once weekly | Topical on scalp after needling |
| Combined copper serum | 0.5 mg AHK-Cu plus GHK-Cu | once daily | Topical on scalp |
| Injectable (community only, no data) | 0.5 to 1 mg | once daily | Subcutaneous near the scalp or abdomen |
Apply to a clean, dry scalp and let it absorb before any other product. Keep it away from vitamin C serums, which reduce the copper. After microneedling, most people wait until the skin has stopped weeping before applying, and skip any product that stings on broken skin.
Sold as a 50 mg lyophilized vial. Most people reconstitute it and apply it to the scalp with a dropper or microneedling; some inject 0.5 to 1 mg subcutaneously. No human dosing data exists for either.
Dose calculator
U-100 insulin syringeUnits are a volume on the syringe, not an amount of peptide. Concentration changes every time you change the water volume. The standalone calculator explains the math.
| Vial | Suggested water | Concentration | Low dose draw |
|---|---|---|---|
| 50 mg | 3 mL | 16.667 mg/mL | 3 units |
How to reconstitute AHK-Cu
- 1
Wash your hands and wipe the work surface. Swab both vial stoppers with alcohol and let them dry.
- 2
Pick the water volume with the calculator above and write it on the vial. The concentration means nothing without it.
- 3
Draw the bacteriostatic water into a mixing syringe.
- 4
Insert at an angle and let the water run down the inside wall. Never squirt it straight onto the powder.
- 5
Swirl gently or leave it to dissolve. Do not shake.
- 6
Label with the date and water volume. Store in the fridge at 2 to 8 C and use within about 4 weeks.
- 7
Unmixed vials keep for months in the fridge and longer in the freezer, sealed and out of light.
- Full walkthrough with syringe reading and site rotation: reconstitution guide.
- ✓White, fluffy cake
Lyophilized powder should look like a small white puck or fluffy cake at the bottom of the vial. That is a proper freeze-dry.
- ✓Clear after mixing
Once dissolved the solution should be water-clear with nothing floating in it.
- !Slight clumping
Small clumps that dissolve with gentle swirling are fine. Shipping compacts powder.
- ✕Collapsed or melted
Powder stuck to the sides, glassy, or shrunken means it got hot in transit. Contact the vendor.
- ✕Cloudy or particles
Persistent cloudiness or visible particles after mixing means degraded or contaminated product. Do not use it.
- Week 1 to 4
No visible hair change; some scalp tingling or mild irritation, especially with microneedling.
- Week 6 to 8
Reduced shedding is the first thing people notice if it is working; a temporary shedding increase can also occur as follicles reset.
- Month 3 to 6
Any thickening or new growth shows up here, matching the timeline of every hair treatment; if nothing has changed by 6 months, it is not working for you.
Interactions and stacking
GHK-Cusynergistic
The two copper tripeptides are routinely combined in scalp serums, AHK-Cu for the follicle and GHK-Cu for surrounding skin.
TB-500compatible
Some hair protocols add TB-500 on the basis of mouse follicle stem cell data; no human data for the pairing.
Minoxidilcompatible
Different mechanisms and often used together; minoxidil has far stronger evidence and should be the base of any protocol.
Finasteride or dutasteridecompatible
The in vitro 5-alpha reductase effect of AHK-Cu is minor next to these drugs; no interaction, and they cover the same target more reliably.
Vitamin C serumscaution
Ascorbic acid reduces the copper complex; apply at different times of day.
Copper metabolism disordersavoid
Anyone with Wilson disease or similar should avoid adding copper peptides, especially if injecting.
Safety
- ▲Scalp irritation, redness or itching, more likely with microneedling
- ▲Temporary increase in shedding in the first weeks
- ▲Blue-green tint on light hair or pillowcases from the copper
- ▲Contact dermatitis in people sensitive to copper
- ▲Injection site pain and bruising in the few who inject it
- ▲Human evidence is limited to one small study; most claims rest on cell culture.
- ▲Copper peptides can irritate the scalp, especially with microneedling. Patch test first.
- ▲It is not a substitute for minoxidil or finasteride, which have far stronger evidence.
- ▲Do not apply with vitamin C serums, which reduce the copper complex.
- ▲Injectable use has no data and is not recommended.
- ■Scalp irritation persists or worsens rather than settling in the first two weeks
- ■Signs of infection at microneedled areas such as heat, pus or spreading redness
- ■A rash or hives beyond the application area
- ■No change at all after 6 months of consistent daily use
Community poll
Self-reported by visitors. Not clinical evidence.AHK-Cu: frequently asked
What is the difference between AHK-Cu and GHK-Cu?
They differ by one amino acid. GHK-Cu occurs naturally in the body and has broad skin and wound healing data. AHK-Cu is a synthetic variant that has been studied mostly for hair follicle stimulation. Many people use both, GHK-Cu for skin and AHK-Cu for scalp.
How do I make a topical solution from the powder?
Reconstitute the vial with sterile or distilled water to the target percentage, for example 50 mg in 5 mL for a 1 percent solution. Some people use a small amount of a penetration enhancer like propylene glycol. Store cold and apply with a dropper to thinning areas.
Does it work for women?
The cell mechanisms apply to any hair follicle and the DHT effect is relevant to female pattern hair loss too. The single clinical study was in men. Women use it in the same way and report similar mixed results.
How long until I see results?
Hair cycles are slow. Reduced shedding may be noticed within 6 to 8 weeks, but new growth or thickening generally takes 3 to 6 months of consistent daily use, which matches the timeline for any hair treatment.
References
- The effect of tripeptide-copper complex on human hair growth in vitro. Archives of Pharmacal Research, 2007
- Copper tripeptide AHK-Cu stimulates dermal papilla cell proliferation and VEGF expression. Journal of Dermatological Science, 2007
- Copper peptides in hair growth and skin regeneration (review). Journal of Cosmetic Dermatology, 2015