What information does a Certificate of Analysis (CoA) for Copper Peptides (GHK-Cu; Glycyl-L-Histidyl-L-Lysine with Copper) contain?

A Certificate of Analysis, also known as CoA, presents the test results of 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 evaluated, using what methods, and with what result. Its value comes from concrete data, not just the title of the document.

A CoA may contain information on identity, purity, 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 data, sample identifier, and dates related to the analysis and approval of results are also useful. The batch number allows linking the certificate to the material described on the label.

The production date, the analysis date, and the document issue date refer to different events. Not every CoA provides the synthesis date. If multiple dates are present, 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 GHK-Cu research 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 complex with copper. Therefore, in the documentation, it is worth checking whether the description and results concern the peptide itself or a material containing the copper complex. Chemical studies of GHK-Cu use various methods to characterize its interactions with copper. Source: Ufnalska et al., 2021.

The empirical formula and molar mass can be part of the description, but they alone do not present 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 transparent CoA, next to the test name, there is a reference to the method, the acceptance criterion, and the obtained result. The criterion states what result was considered appropriate. The result shows what was found in the tested sample. Distinguishing between 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
Batch number	Which material were the results associated with?
Name of the test	What property was evaluated?
Method or its designation	How was the evaluation conducted?
Acceptance criterion	Which result meets the accepted requirement?
Result and unit	What was determined during the analysis?
Application for conformity	Does the result fall within the specified criterion?

HPLC purity: what does the percentage mean?

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

Chromatographic purity can be calculated as the ratio of the peak area assigned to the tested compound to 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 Bachem's 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 must 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 important that it can be linked to the correct sample and analysis. The chart image alone without a description does not provide a complete basis for evaluation.

Mass spectrometry: what information does MS provide?

Mass spectrometry, abbreviated as MS, analyzes ions based on their mass-to-charge ratio. Consistency with the expected value can support the identification of the tested component. However, it is not independent proof of all the details of its structure.

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

Therefore, the statement „HPLC 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 answers the question of how much of a specific component is present in the sample. This is distinct information from the purity of HPLC. The result should include a 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, so it should not be automatically treated as an impurity. At the same time, measuring the total amount of copper does not determine in itself how much of it remains bound to the peptide. Evaluating the amount of the element and characterizing the complex are two different analytical tasks.

Appearance, water, and production residues

A CoA may describe the color and form of the material. The blue color is a secondary characteristic, not sufficient proof of identity or purity. Likewise, the term „lyophilized” describes how the material form was obtained, not the result of a full quality assessment.

Additional designations may include water content, tested for example using the Karl Fischer method. This information helps 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 list residual solvents or specific elemental impurities. A useful record indicates what was tested, what result was obtained, and what limit it was compared against. A general statement of „no impurities” does not replace such a description.

Microbiological and endotoxin testing

Some certificates include microbiological testing or the determination of endotoxins, which are components derived from specific bacteria. These are separate 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 together with the method, unit, and given limit. „Below the limit of quantification” means that the method did not allow for a reliable determination of the amount below the specified level. This is not synonymous with stating the complete absence of the given component.

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

Document storage, dates, and approval

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

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

How to evaluate 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.

The mere statement „in accordance with the specification” does not imply compliance with every possible application. Nor does the CoA guarantee material stability following improper storage, or identical results across different experiments.

Disclaimer

The article explains how to read GHK-Cu analytical documentation. It does not evaluate a specific batch or product. The certificate of analysis does not constitute standalone 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 needed to fully evaluate 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 regarding the concept of the 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 & Concentration Calculator. The explanation of the difference between purity and peptide content was used.
5. FDA. Pyrogen and Endotoxins Testing: Questions and Answers. Analytical distinctions, not research limits, were utilized for GHK-Cu.