A Certificate of Analysis (COA) is the lab report behind a research compound. It tells you what was tested, how it was tested and what the results were. Knowing how to read one takes a few minutes, and it is the single best way to judge whether a supplier’s quality claims hold up.
This guide walks through each section of a typical peptide COA, using the layout of the independent HPLC-UV reports we publish for Atlas Amino products.
1. Report details
The top of a COA identifies the report itself: a report number, the date it was generated, and often a verification ID. These let you confirm the document is genuine and match it to the product you are buying. A COA with no report number or no testing lab named is a warning sign.
2. Sample identification
This section records which compound was tested, who requested the test, and the key dates: when the sample was requested, received, tested and reported. Check two things here:
- The compound and strength match the product. A report for a 20 mg vial tells you about that strength, not automatically about a 10 mg vial of the same compound.
- The dates are recent enough to be relevant to the stock being sold.
Some reports also list a lot or batch number. When a lot number is present, it ties the results to a specific production run.
3. Purity (HPLC)
Purity is usually measured by high-performance liquid chromatography (HPLC). The sample is separated into its components, and a detector measures each one. Purity is the main peak’s share of everything detected, expressed as a percentage.
For research peptides, results of 98% and above are generally considered high purity. Our published reports, for example, range from 98.57% to 99.96%.
4. Content and fill accuracy
Purity tells you what share of the material is the target peptide. Content tells you how much material is actually in the vial. A good COA lists both the expected amount and the measured mass, plus the fill accuracy as a percentage of the label claim.
| Field | What it means |
|---|---|
| Expected content | The amount stated on the label, for example 10.00 mg |
| Measured mass | The amount the lab actually found in the vial |
| Fill accuracy | Measured mass divided by expected content |
A result slightly above 100% is common, because vials are often filled with a small overage. A result well below 100% means the vial holds less than the label states.
5. The chromatogram
Most HPLC reports include a chart called a chromatogram. The x-axis is time and the y-axis is detector response. A single tall, sharp peak with little else around it indicates a clean sample. Several sizeable secondary peaks suggest impurities or degradation.
6. Appearance
Lyophilized peptides are usually recorded as a white powder. Some compounds have a characteristic color, such as GHK-Cu, which is blue because of its bound copper. If the appearance in the report doesn’t match what arrives, ask the supplier about it.
Quick checklist
- A named, independent testing laboratory
- A report number you can match to the product
- The same compound and strength as the product you are buying
- An HPLC purity result, ideally 98% or higher
- Measured content close to the label amount
- A recent test date
You can review every Atlas Amino report on our Certificates of Analysis page, and each product page summarizes its report’s key numbers.
Atlas Amino products are sold for laboratory research use only. They are not for human or animal use. This article is for general information and is not medical or legal advice.