GHK-Cu
Gly-His-Lys copper complex · Copper Tripeptide-1
Naturally occurring copper-binding tripeptide researched for collagen signalling, skin quality, extracellular-matrix remodelling and tissue repair.
Reference dose
1–2.5 mg
Source-specific educational reference, not an individualized recommendation.
Reference schedule
3× weekly · 6–8 weeks
New to peptide research?
This page gets detailed quickly.
Profiles include evidence, formats, units, source-specific reference amounts and, where relevant, device details. If any of those terms are unfamiliar, do not guess your way through them. Start with a Personalised Guide and we will put the foundations in the right order for you.
At a glance
Structure
Gly-His-Lys + Cu²⁺
A three-amino-acid peptide complexed with copper.
Best direct human evidence
Topical skin studies
Small studies have assessed collagen and wrinkle-related outcomes.
Main research focus
Skin + extracellular matrix
Collagen, elastin, matrix remodelling and repair biology.
Also called
Copper Tripeptide-1
Common cosmetic ingredient name for GHK-Cu.
What it is
GHK-Cu is the copper complex of GHK, a naturally occurring tripeptide made from glycine, histidine and lysine. GHK binds copper(II) strongly, creating the blue copper-peptide complex commonly called Copper Tripeptide-1 in cosmetic formulations.
GHK was originally identified in human plasma and is also found in other body fluids. Research has focused on its relationship with tissue remodelling, fibroblast function and copper-dependent biology.
Research focus
How it works
GHK is the tripeptide glycyl-L-histidyl-L-lysine. It binds copper(II) to form GHK-Cu, a complex studied for fibroblast signalling, collagen and elastin production, matrix remodelling and repair-related pathways.
Important context
GHK-Cu has a meaningful topical skin-research history, but topical cosmetic evidence and injectable research are not interchangeable. The strongest direct human evidence on this page is from topical formulations.
What it is studied for
Skin and cosmetic research focuses on collagen and elastin production, firmness, wrinkle appearance, extracellular-matrix turnover and recovery from skin damage.
Repair research explores wound contraction, angiogenesis, inflammatory signalling and tissue-remodelling pathways.
Hair and scalp applications are also discussed because copper-peptide signalling has been studied around follicles and skin biology, although direct human hair-growth evidence remains comparatively limited.
More contextWhy GHK-Cu gets so much attentionSee the deeper context, evidence details and practical distinctions behind this profile.
GHK-Cu combines a very small naturally occurring peptide with copper, an element used by enzymes involved in connective-tissue biology. That makes it interesting as both a signalling peptide and a copper-carrying complex.
Most of the excitement around GHK-Cu comes from skin and extracellular-matrix research: collagen and elastin production, matrix remodelling, skin firmness, wrinkle appearance and repair-related signalling.
- Small human topical studies have reported improvements in procollagen production and measured wrinkle parameters.
- Cell and animal studies add a much larger mechanistic literature around fibroblasts, collagen, elastin, glycosaminoglycans, MMP/TIMP balance and wound repair.
- Hair and scalp applications are widely discussed, but the direct human evidence is much thinner than the topical skin literature.
Why people are interested
What makes GHK-Cu worth researching.
Human topical + cell research
Collagen & skin firmness
Human topical and cell studies have reported increased procollagen/collagen-related activity and improvements in measures linked with skin firmness.
Small human studies
Wrinkle appearance
Small topical studies have reported reductions in measured wrinkle volume or depth, although formulations, delivery systems and study quality vary.
Cell + preclinical
Extracellular-matrix remodelling
GHK-Cu has been studied for effects on fibroblasts, collagen, elastin, glycosaminoglycans and the balance of matrix metalloproteinases and their inhibitors.
Mostly preclinical
Repair & wound biology
Animal and laboratory studies have repeatedly explored GHK-Cu in wound-healing, angiogenesis and tissue-remodelling models.
Evidence
Where the evidence is strongest, and what kind of evidence it is.
Human · small studies
Topical skin outcomes
A one-month biopsy study reported increased procollagen synthesis in 7 of 10 GHK-Cu-treated volunteers. An eight-week nanocarrier study reported improved wrinkle-volume measures versus vehicle and a Matrixyl 3000 comparator.
Human · mixed
Post-procedure skin
In a 13-patient randomized study after CO2 laser resurfacing, objective erythema and wrinkle/skin-quality measures did not differ significantly between regimens, although patient-reported overall skin quality favored GHK-Cu.
Cell / animal
Matrix & repair mechanism
A broader preclinical literature reports effects on fibroblast activity, collagen, elastin, glycosaminoglycans, matrix-remodelling enzymes and wound-repair models.
Limited human data
Injectable use
The human literature supporting injectable GHK-Cu is far thinner than the topical literature. Injectable research references should not be presented as if they came from the cosmetic clinical studies.
Human research
A small one-month human biopsy study summarized in later reviews included 20 volunteers; among the 10 participants using topical GHK-Cu, 7 showed increased procollagen synthesis. The study was small and used thigh skin rather than a large facial anti-ageing trial.
An eight-week study of a nano-carrier GHK-Cu facial serum in women reported greater wrinkle-volume improvement than vehicle and a commercial Matrixyl 3000 comparator, with wrinkle-depth improvement versus vehicle. Delivery system and formulation are important parts of that result.
A randomized study in 13 patients after CO2 laser resurfacing found no significant objective difference in erythema resolution or investigator-rated wrinkle/skin-quality outcomes, while a patient questionnaire favored GHK-Cu for overall skin-quality improvement.
Reviews also describe older facial and eye-area cosmetic studies reporting improvements in laxity, firmness and wrinkle appearance, but several of those older reports are less accessible and less well documented than modern clinical trials.
Preclinical research
Human dermal fibroblast studies have reported increased collagen and elastin production and changes in MMP/TIMP expression consistent with extracellular-matrix remodelling.
Animal wound models have reported increased collagen, glycosaminoglycan and other connective-tissue measures after GHK-Cu exposure.
Laboratory research has explored anti-inflammatory, antioxidant, angiogenic and gene-expression effects that may help explain the broad repair-oriented research interest around GHK-Cu.
Reference dosing
Reference amount, schedule and conversion.
A reference amount is only useful when you know the formulation, concentration and delivery device it belongs to. Do not transfer a vial amount into a pen, a pen click count into another pen, or a syringe-unit number into a different concentration.
01
Identify the format
Vial, reusable cartridge pen, prefilled multi-dose pen or single-dose autoinjector.
02
Confirm concentration
Know the total peptide amount and liquid volume or the manufacturer/vendor concentration.
03
Understand the units
Keep mg/mcg, mL and syringe units or device clicks separate.
04
Then use the reference
Only convert a known reference amount with the calculator that matches the actual device.
Source-specific reference
1–2.5 mg
3× weekly · 6–8 weeks
The 1–2.5 mg range is the injectable research reference shown on The Pep Report. It is separate from the topical human studies summarized on this page; topical products use formulation-specific concentrations.
Calculator connection
Choose the calculator that matches the actual formulation. The calculator converts numbers you already know; it does not choose the target amount.
A 100 mg pen describes the total peptide in the cartridge, not the amount represented by one click. Click amount depends on the cartridge's total strength and click scale.
Storage
Start with the format. Then verify the exact product.
Rule of thumb, not a product instruction
Rule of thumb only: GHK-Cu storage depends heavily on formulation chemistry. A finished topical product, a research vial and a premixed pen or cartridge should not be assumed to share the same stability conditions.
Pen rule of thumb
For a premixed GHK-Cu pen or cartridge, protect it from unnecessary heat and light and follow the exact supplier's validated in-use window. Do not import a storage period from a different cartridge or from a topical product.
Vial rule of thumb
For a GHK-Cu vial, keep dry and reconstituted states separate. Once liquid is added, concentration, pH, diluent, container and repeated handling become part of the stability question.
Topical rule of thumb
For topical GHK-Cu, follow the finished cosmetic's label because the vehicle, preservatives, antioxidants, pH and packaging are part of the product's stability system.
Known data
For GHK-Cu, the strongest storage data comes from formulation and chemical-stability research rather than an approved injectable drug label. Published work shows that GHK-Cu stability is condition-dependent and that oxidative stress can contribute to degradation.
For GHK-Cu, published formulation research also shows why pH, excipients, delivery system and packaging matter. These variables can alter chemical stability and delivery even when the ingredient name on the front of the product is the same.
Formulation context
For GHK-Cu, formulation context matters because a topical serum, cream or gel contains a vehicle, preservatives, pH controls and packaging that help determine stability. Those data do not establish the shelf life of an injectable preparation.
For GHK-Cu, an injectable research formulation adds different concerns, including diluent, concentration, sterility, aggregation, container closure and peptide-related impurities. FDA has separately highlighted aggregation and impurity concerns for compounded injectable GHK-Cu.
What is not established
For GHK-Cu, what remains unestablished is a universal refrigeration period, post-reconstitution lifetime, freeze-thaw limit or room-temperature allowance for research injectable preparations.
For GHK-Cu, degradation studies can identify conditions that may damage the molecule, but they do not create a validated consumer shelf life unless the exact finished formulation has been tested.
Sources
The sources below support the product-specific storage distinctions above.
Practical reference
Formats
Topical
Vial / injectable research formats
Reconstitution & units
The 1–2.5 mg research reference applies to injectable research discussion, not to topical creams or serums.
If using a vial format, the total peptide amount and the exact liquid volume added determine the concentration used by the calculator.
mg or mcg describe peptide amount; mL describes liquid volume; U-100 units describe syringe volume; pen clicks are device increments.
A 100 mg pen is the total cartridge strength, not a 100 mg dose.
Safety, status & open questionsOpen the practical cautionsTopical Copper Tripeptide-1 is widely used as a cosmetic ingredient. Injectable GHK-Cu is a different regulatory and evidence question: human safety data are limited, and FDA has specifically flagged compounded injectable GHK-Cu for potential immunogenicity risks related to aggregation and peptide impurities.
Open questions
The human topical evidence is promising but relatively small, and many positive studies use specific creams, serums or delivery systems. Results from one formulation cannot automatically be assigned to every product containing GHK-Cu.
GHK-Cu is hydrophilic, so skin penetration and formulation design matter. Recent reviews continue to identify delivery and permeability as important practical variables.
Human evidence for injectable systemic GHK-Cu is limited compared with the topical skin literature.
Hair-growth claims are biologically plausible and common in cosmetic discussion, but they do not currently have the same direct human evidence depth as the skin/collagen use case.
Regulatory notes
Topical Copper Tripeptide-1 is used in cosmetics; that does not make a cosmetic product an FDA-approved drug for treating disease.
As of 2026, FDA lists GHK-Cu except injectable routes in its 503A Category 1 evaluation process for bulk substances. That is an interim compounding-policy category, not an FDA approval of GHK-Cu as a drug.
FDA separately states that compounded injectable GHK-Cu may pose immunogenicity risk because of aggregation and peptide-related impurities and notes limited human safety data for injectable use.
Practical notes
Topical products can cause irritation or sensitivity in some users; tolerability also depends on the complete formulation, not GHK-Cu alone.
Injectable compounded peptide products add route-specific concerns including sterility, impurities, aggregation and immunogenicity. FDA specifically flags these issues for injectable GHK-Cu.
Copper-metabolism disorders or clinically significant copper imbalance are reasons to discuss copper-containing products with an appropriate clinician rather than treating GHK-Cu as ordinary copper supplementation.
Common mistakes
Treating topical cosmetic evidence as evidence for injectable GHK-Cu.
Using the 1–2.5 mg injectable research reference as if it were a topical concentration.
Confusing a 100 mg pen strength with the amount delivered per click.
Assuming every product labelled 'copper peptide' contains the same GHK-Cu concentration or delivery system.
Assuming a strong mechanism automatically predicts the same magnitude of effect in every finished product.
Common questions
Is GHK-Cu the same as Copper Tripeptide-1?
Yes. Copper Tripeptide-1 is the common cosmetic ingredient name for the copper complex of the GHK tripeptide.
What is GHK-Cu mainly researched for?
The strongest recurring research themes are skin quality, collagen and elastin biology, extracellular-matrix remodelling and tissue repair. Hair/scalp applications are also discussed, but the direct human evidence is less developed.
Does topical GHK-Cu have human evidence?
Yes, but the studies are generally small. Published and review-reported studies include procollagen biopsy outcomes and wrinkle/skin-quality measures using specific topical formulations.
Is the 1–2.5 mg reference a topical dose?
No. That Pep Report research range is an injectable research reference. Topical products use formulation-specific concentrations and application instructions.
How long did topical studies run?
Human studies discussed in the literature include roughly one-month, eight-week and twelve-week observation periods, depending on the formulation and outcome being measured.
Can I use the Pep Report calculator for a GHK-Cu vial or pen?
Yes for arithmetic when you already know the total strength, liquid volume or pen strength, and the target amount from the reference you are following. The calculator does not choose the target amount.
Related peptides & blends
GLOW
Vendor/community blend name for a co-formulation of GHK-Cu, BPC-157 and TB-500; evidence comes from the individual components rather than the three-peptide blend itself.
Open reference →KLOW
Four-peptide research blend combining GHK-Cu, BPC-157, TB-500 and KPV; the evidence base belongs to the individual components rather than the co-formulation.
Open reference →BPC-157
Synthetic 15-amino-acid peptide with extensive animal research in tissue-repair and gastrointestinal models but very limited human evidence.
Open reference →References
Topically applied GHK as an anti-wrinkle peptide — review
BioImpacts / PMC · 2025
Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin
PubMed · 2006
Peptides and skin senescence — review
PMC · 2025
FDA — compounded bulk substances that may present significant safety risks
U.S. FDA · 2026
Regenerative and Protective Actions of the GHK-Cu Peptide
PMC · 2018
FDA — 503A bulk drug substances under evaluation
U.S. FDA · 2026