A researcher's guide to sourcing high-purity GHK-Cu copper peptide: quality indicators, Certificate of Analysis verification, copper content analysis, and what distinguishes research-grade material from inferior products. For laboratory research use only.
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GHK-Cu (glycyl-L-histidyl-L-lysine copper(II)) is a naturally occurring tripeptide-copper complex first isolated from human plasma in 1973. The peptide consists of three amino acids — glycine, histidine, and lysine — chelated to a copper(II) ion with a high binding affinity (log K = 16.44). With a molecular weight of approximately 403.93 g/mol and the CAS registry number 49557-75-7, GHK-Cu is one of the most widely studied copper-binding peptides in laboratory research.
GHK-Cu is investigated across multiple research domains including gene expression profiling, extracellular matrix biology, copper homeostasis, and dermatological science. Microarray studies have demonstrated that GHK-Cu affects the expression of over 4,000 human genes, making it a valuable tool for transcriptomics and gene regulation research. For a comprehensive overview of GHK-Cu's molecular structure, mechanisms, and laboratory applications, see our GHK-Cu research peptide guide.
Because GHK-Cu's biological activity depends directly on proper copper chelation, sourcing decisions carry more significance than with many other research peptides. Improperly manufactured or degraded GHK-Cu can compromise experimental outcomes, making supplier evaluation a critical step in any research protocol involving this compound.
GHK-Cu presents unique sourcing challenges that distinguish it from standard research peptides. The presence of the copper(II) ion introduces additional quality variables that researchers must account for when selecting a supplier.
First, the copper chelation itself must be verified. Unlike single-chain peptides where purity analysis confirms the product, GHK-Cu requires confirmation that the copper ion is properly bound to the tripeptide in the correct stoichiometric ratio. Free copper and uncomplexed GHK peptide behave differently in research assays and can introduce confounding variables into experimental results.
Second, copper peptides are susceptible to degradation pathways that do not affect standard peptides. Exposure to chelating agents, improper pH conditions during manufacturing, or inadequate lyophilization can disrupt the copper-peptide bond. These degradation products may not be immediately obvious without proper analytical testing.
Third, the visual characteristics of GHK-Cu provide a baseline quality indicator that researchers can use immediately upon receipt. Genuine GHK-Cu lyophilized powder is blue to blue-green in color due to the copper ion. White, colorless, or off-white powder indicates that the copper is absent or improperly chelated — a clear sign of a substandard product.
For researchers who are new to evaluating peptide suppliers, our guide on how to evaluate a peptide vendor provides a detailed framework covering COA interpretation, red flags, and quality benchmarks applicable across all research peptides.
When evaluating where to buy GHK-Cu, the following analytical quality indicators should be verified before purchase. These represent the minimum standards for research-grade copper peptide material.
High-Performance Liquid Chromatography (HPLC) is the standard method for assessing peptide purity. Research-grade GHK-Cu should demonstrate ≥98% purity on HPLC analysis, with clearly identified peaks and minimal impurity signals. The HPLC chromatogram should be included in the supplier's Certificate of Analysis for each production batch.
HPLC testing confirms the absence of synthesis byproducts, truncated sequences, and other peptide-related impurities. However, HPLC alone does not confirm copper chelation status, which is why additional analytical methods are required for GHK-Cu specifically.
Mass spectrometry (MS) provides molecular weight confirmation and sequence verification. For GHK-Cu, the expected molecular weight is 403.93 g/mol for the copper complex. If the MS data shows a molecular weight closer to 340.38 g/mol, this indicates the free GHK peptide without copper — a fundamentally different research material.
Electrospray ionization mass spectrometry (ESI-MS) or matrix-assisted laser desorption/ionization (MALDI) are both suitable techniques for GHK-Cu identity confirmation. The mass spectrum should be available as part of the supplier's quality documentation.
This is the quality indicator most specific to GHK-Cu and the one most commonly overlooked by researchers unfamiliar with metallopeptides. Copper content analysis confirms that the Cu²+ ion is present in the correct stoichiometric ratio with the GHK peptide.
Analytical methods for copper verification include inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectroscopy (AAS), and elemental analysis. These techniques quantify the copper content and confirm that the copper-to-peptide ratio matches the expected value for properly chelated GHK-Cu.
Suppliers that provide copper content data alongside HPLC and MS results demonstrate a thorough understanding of the compound and a commitment to quality that extends beyond standard peptide testing.
The Certificate of Analysis (COA) is the single most important document when evaluating a GHK-Cu supplier. A comprehensive COA for GHK-Cu should include the following elements:
Suppliers that provide incomplete COA documentation — or no COA at all — should be avoided regardless of pricing. The absence of batch-specific quality data introduces unacceptable uncertainty into research outcomes and undermines experimental reproducibility.
Proper storage is essential for maintaining GHK-Cu integrity after purchase. Incorrect storage conditions can degrade the copper-peptide bond or the peptide backbone itself, rendering the compound unsuitable for research. Understanding these requirements before purchase ensures your laboratory is prepared to handle the material upon arrival.
Unreconstituted GHK-Cu in lyophilized form should be stored at -20°C, protected from light and moisture. Under these conditions, the compound remains stable for 24 months or longer. The sealed vial should be kept in a desiccated environment to prevent moisture absorption, which can initiate degradation. Upon removal from cold storage, allow the sealed vial to equilibrate to room temperature before opening to prevent condensation from contacting the powder.
Once reconstituted with bacteriostatic water, GHK-Cu solutions should be stored at 2-8°C (standard refrigerator temperature) and used within 3-4 weeks. The benzyl alcohol preservative in bacteriostatic water inhibits microbial growth and extends the usable life of the reconstituted peptide compared to sterile water. For detailed reconstitution protocols, refer to our complete guide to peptide reconstitution.
GHK-Cu requires additional handling precautions beyond standard peptide protocols. Avoid contact with chelating agents such as EDTA, DTPA, or EGTA, as these compounds can strip the copper ion from the GHK peptide. Additionally, extreme pH conditions (below pH 4 or above pH 9) can destabilize the copper-peptide bond. When preparing buffers for GHK-Cu research, verify that no components in the buffer system have chelating properties that could interfere with the copper complex.
A faint blue tint in the reconstituted solution is normal and expected — it confirms the presence of the copper(II) ion. Loss of the blue color over time may indicate copper dissociation and compound degradation.
PeptidesATX provides research-grade GHK-Cu (50mg) manufactured to meet the quality standards that copper peptide research demands. Every batch is verified through HPLC purity analysis, mass spectrometry identity confirmation, and copper content testing to ensure proper Cu²+ chelation.
All products ship with batch-specific Certificates of Analysis documenting purity, identity, and analytical results from third-party testing. This documentation provides the quality assurance researchers need for reproducible experimental outcomes.
For researchers investigating multi-pathway approaches to dermatological and extracellular matrix research, PeptidesATX also offers the GLOW research blend (70mg), which combines GHK-Cu with BPC-157 and TB-500 for studying complementary tissue remodeling pathways. Supporting materials including bacteriostatic water (10mL) are available to streamline laboratory preparation.
PeptidesATX compounds are intended exclusively for laboratory research use. All products are supplied as lyophilized powders with proper cold-chain shipping to preserve compound integrity during transit.
Whether purchasing from PeptidesATX or evaluating alternative sources, use the following criteria to assess any GHK-Cu supplier:
GHK-Cu research peptide can be purchased from specialized peptide suppliers such as PeptidesATX. When selecting a supplier, verify that they provide third-party Certificates of Analysis (COA), HPLC purity testing showing ≥98% purity, and mass spectrometry confirmation. Research-grade GHK-Cu should include copper content verification to ensure proper Cu²+ chelation. All purchases are for laboratory research use only.
Quality verification for GHK-Cu requires reviewing the supplier's Certificate of Analysis (COA) for HPLC purity data (≥98%), mass spectrometry results confirming the correct molecular weight of 403.93 g/mol, and copper content analysis verifying proper Cu²+ chelation. The lyophilized powder should be blue to blue-green in color — white or colorless powder indicates absent copper. Endotoxin testing is recommended for cell culture research applications.
Copper content verification is critical because GHK-Cu's research utility depends on the copper(II) ion being properly chelated to the tripeptide. Improperly manufactured GHK-Cu may contain free (uncomplexed) copper, which behaves differently in research assays, or the peptide may lack copper entirely. Analytical methods such as ICP-MS or atomic absorption spectroscopy confirm the copper-to-peptide stoichiometry in research-grade material.
Lyophilized GHK-Cu should be stored at -20°C, protected from light and moisture. Once reconstituted with bacteriostatic water, store the solution at 2-8°C and use within 3-4 weeks. Avoid repeated freeze-thaw cycles and contact with chelating agents such as EDTA that can strip the copper ion from the peptide complex. The strong copper chelation bond contributes to the compound's stability in proper storage conditions.
GHK-Cu is the copper-complexed form of the tripeptide with a molecular weight of 403.93 g/mol, while free GHK (without copper) has a molecular weight of 340.38 g/mol. The copper(II) ion is essential for many of GHK-Cu's studied biological activities, including its roles in metalloprotein support and gene expression modulation. When purchasing for research, ensure the product is the copper-chelated form (CAS 49557-75-7) unless your protocol specifically requires the free peptide.
Access quality documentation and research-grade GHK-Cu for your laboratory investigations.
View Certificate of Analysis Explore Research-Grade PeptidesDisclaimer: This compound is intended for laboratory research use only. It is not approved for human or veterinary use. All research should be conducted in accordance with institutional guidelines and applicable regulations. No information in this article constitutes medical advice, dosing guidance, or therapeutic recommendation.