A Certificate of Analysis (CoA) for Copper Peptides (GHK-Cu; glycyl-histidyl-lysine with copper) typically contains the following information: * **Product Name:** Copper Peptide (GHK-Cu) * **CAS Number:** (The CAS number for GHK-Cu) * **Molecular Formula:** (The molecular formula of GHK-Cu) * **Molecular Weight:** (The molecular weight of GHK-Cu) * **Batch/Lot Number:** A unique identifier for the specific batch of product. * **Date of Manufacture:** The date the batch was produced. * **Date of Expiry/Retest Date:** The recommended date for re-evaluation or expiration. * **Appearance:** A description of the physical state and colour of the product (e.g., white to off-white powder). * **Purity:** The percentage of GHK-Cu in the sample, usually determined by High-Performance Liquid Chromatography (HPLC). Often expressed as ≥ 98% or ≥ 99%. * **Identity Confirmation:** * **HPLC Retention Time:** The time it takes for GHK-Cu to pass through the HPLC column, compared to a reference standard. * **Mass Spectrometry (MS) or Nuclear Magnetic Resonance (NMR):** Spectroscopic data confirming the molecular structure. * **Copper Content:** The percentage of copper present in the peptide complex. This is crucial for confirming it is indeed the copper complex. * **Moisture Content/Water Content:** The amount of water present in the sample, often determined by Karl Fischer titration. * **Solubility:** Information on how well the peptide dissolves in specific solvents (e.g., water, DMSO). * **pH:** The pH of a solution of the peptide at a specified concentration. * **Endotoxin Level (if applicable):** For certain applications (e.g., research in cell culture), the level of bacterial endotoxins may be tested and reported. * **Storage Conditions:** Recommended conditions for storing the product to maintain its stability and integrity (e.g., refrigerated, protected from light). * **Manufacturer Information:** Name and address of the company that manufactured and/or supplied the product. * **Analyst's Signature/Name and Date:** The name or signature of the quality control analyst who performed the tests and the date the analysis was completed. * **Quality Control Approval:** The name or signature of the person responsible for approving the CoA.

A Certificate of Analysis, also known as a CoA, presents the test results for a sample associated with a specific batch of material. In the case of GHK-Cu, it helps to verify which properties of the copper peptide were assessed, using which methods and with what outcome. Its value derives from concrete data, rather than the title of the document itself.

A CoA may contain information on identity, purity, the content of individual ingredients and additional quality parameters. The scope of analyses depends on the adopted specification, which is a set of requirements for the material. It should not be assumed that every certificate for GHK-Cu includes all the tests listed below.

Identification data: which party do the results concern?

Basic information includes the material name, batch number and document designation. Issuer details, sample identifier and dates related to the analysis and approval of results are also useful. The batch number allows the certificate to be linked to the material described on the label.

The manufacturing date, the analysis date and the document issue date refer to different events. Not every CoA provides the synthesis date. If there are several dates, their descriptions should clearly indicate what they refer to.

Such elements are also described by the CoA model published by the WHO. The WHO document concerns quality control in the pharmaceutical sector; it does not constitute a ready-made, mandatory specification for every research-grade GHK-Cu material. Source: WHO — model certificate of analysis.

Name and chemical description of GHK-Cu

GHK stands for the peptide with the sequence Gly-His-Lys, composed of glycine, histidine and lysine residues. GHK-Cu refers to its copper complex. In documentation, therefore, it is worth checking whether the description and results relate to the peptide itself or to a material containing the copper complex. Chemical studies of GHK-Cu use various methods to characterise its interactions with copper. Source: Ufnalska et al., 2021.

The empirical formula and molar mass may form part of the description, but on their own they do not represent the full structure. It is also important to indicate the form of the material, especially when it contains water or additional components. Parameters assigned to a specific molecule do not necessarily describe the entire contents of the sample.

Method, requirement and result — how to read an analytical table?

In a clear CoA, next to the test name, there is a reference to the method, the acceptance criterion, and the obtained result. The criterion states which result was considered appropriate. The result shows what was found in the tested sample. Distinguishing these elements is the basis for describing the analytical specification. Source: ICH Q6A.

For example, the entry „requirement: at least 98%” is not yet a measurement result. Only a separate value in the results column shows the outcome of the analysis. The number 98% is an example here, not a universal threshold for GHK-Cu.

Document element	Question answered by
Batch number	With which material were the results associated?
Test name	What property was assessed?
Method or its designation	How was the assessment carried out?
Acceptance criterion	Which result meets the accepted requirement?
Result and unit	What was established during the analysis?
Application of conformity	Does the result fall within the specified criterion?

HPLC purity: what does the percentage value mean?

HPLC is a method for separating sample components. The result is often presented as a chromatogram, which is a graph of signals recorded during analysis. The peaks visible on it help to assess the composition of the sample within the capabilities of the method used.

Chromatographic purity can be calculated as the proportion of the peak area assigned to the tested compound in the sum of selected peak areas. It does not automatically represent the percentage content of GHK-Cu in the total mass of the material. Water, counterions and other components may not be included in such a result. The difference between peptide purity and its content is explained in the Bachem technical documentation. Source: Bachem — peptide content.

The largest peak does not automatically become a confirmed GHK-Cu signal just because it dominates the chart. One needs to know how it was assigned to a specific component. Smaller peaks also require interpretation; their size alone does not explain their origin.

A chromatogram can be an attachment to a CoA. It is essential that it can be linked to the correct sample and analysis. The chart image alone without a description does not provide a full basis for evaluation.

Mass spectrometry: what information does MS provide?

Mass spectrometry, abbreviated as MS, analyses ions based on their mass-to-charge ratio. Agreement with the expected value can support the identification of the test component. However, it is not standalone evidence for all the details of its structure.

With GHK-Cu, it is important to indicate which chemical form the signal has been assigned to. The result for the peptide moiety and the result for the copper complex answer different questions. The interpretation should take into account the analysis conditions and the possibility of changes in the system under investigation during the measurement.

Therefore, the statement „PLC and MS confirm the correct structure” requires clarification. These methods can provide complementary data, but the scope of confirmation depends on what was actually measured.

Peptide and copper content

The assay determination answers the question of how much of a specific component is present in the sample. This is separate information from the purity of HPLC. The result should include a given unit and a clearly defined basis, for example, referring to the material as received or after accounting for water content.

Copper is an intended component of GHK-Cu, therefore it should not be automatically treated as an impurity. At the same time, the measurement of total copper does not in itself determine what proportion of it remains bound to the peptide. The assessment of the amount of the element and the characterisation of the complex are two different analytical tasks.

Appearance, water and production residues

A CoA may describe the colour and physical form of the material. The blue colour is a supplementary feature and not sufficient proof of identity or purity. Similarly, the term „lyophilised” describes the method used to obtain the physical form of the material, not the result of a full quality assessment.

Among the additional designations, there may be the water content, determined for example by the Karl Fischer method. This information helps to interpret the composition and mass of the sample. However, a single water content result does not independently determine the durability of the material.

The document may also mention residual solvents or specific elemental impurities. A useful record indicates what was tested for, what result was obtained, and what limit it was compared against. A general statement such as „no impurities” does not replace such a description.

Microbiological tests and endotoxins

Some certificates include microbiological testing or the determination of endotoxins, which are components derived from certain bacteria. These are distinct parameters. The endotoxin test is not a sterility test, and the microbiological result does not replace the endotoxin determination. Source: FDA — Pyrogen and Endotoxins Testing: Questions and Answers.

The result should be read in conjunction with the method, unit and given limit. „Below the limit of quantification” means that the method did not allow the quantity to be reliably determined below the specified level. It is not equivalent to stating that the given component is completely absent.

If the CoA does not include such a test, sterility or a low level of endotoxins cannot be attributed to the material on this basis.

Document storage, dates and approval

The certificate may specify storage conditions, expiry date or retest date. It is worth checking which term has actually been used, rather than treating all dates as equivalent. Storage recommendations should refer to the described form of the material.

Approval by an authorised person indicates who accepted the document. It does not automatically mean that the analysis was performed by an independent laboratory. The issuer and testing laboratory data help establish the origin of the results. The scope of such information takes into account the WHO CoA model. Source: WHO.

How to assess the suitability of a CoA for a specific study?

The most useful certificate allows you to combine three pieces of information: what material was tested, what was measured, and what requirements were applied. This makes it possible to assess whether the document covers parameters relevant to the planned experiment.

Simply writing „conforming to specification” does not mean suitability for every possible application. Nor does a CoA guarantee that the material will remain unchanged after improper storage or that identical results will be obtained in different experiments.

Disclaimer

The article explains how to read GHK-Cu analytical documentation. It does not evaluate a specific batch or product. A certificate of analysis does not in itself constitute confirmation of clinical safety or the suitability of the material for human use.

The content is for educational and informational purposes only. Further research is required to fully assess the safety and efficacy of this peptide. Research products offered by suppliers such as Semax Polska are intended exclusively for scientific and laboratory applications.

References

1. WHO. (2018). WHO model certificate of analysis. TRS 1010, Annex 4.
2. I. Q6A: Specifications—Test Procedures and Acceptance Criteria for New Drug Substances and New Drug Products: Chemical Substances. Source concerning the concept of specification; does not establish universal requirements for research-grade GHK-Cu.
3. Ufnalska, I., et al. (2021). Intermediate Cu(II)-Thiolate Species in the Reduction of Cu(II)GHK by Glutathione: A Handy Chelate for Biological Cu(II) Reduction. Inorganic Chemistry, 60(23), 18048–18057.
4. Bachem. Peptide Content and Concentration Calculator. The explanation of the difference between purity and peptide content was utilised.
5. FDA. Pyrogen and Endotoxins Testing: Questions and Answers. Analytical distinctions were used, not limits for research GHK-Cu.