How to Read a COA
Last updated: September 2026
A Certificate of Analysis (COA) is the document that verifies a peptide batch has been tested for identity, purity, and potency. Here is how to read one and what to look for.
What a COA Is
A COA is a lab-issued document that records the test results for a specific batch of a product. It confirms that the product meets quality specifications and documents identity, purity, concentration, and any contaminants. A legitimate vendor should provide a COA for every batch they sell.
Key Sections to Check
Product & Batch Info
Verify the product name, catalog number, and batch/lot number match what you ordered. The date of analysis tells you when it was tested.
Identity Test (HPLC / Mass Spec)
Confirms the substance is what the label says it is. HPLC (High-Performance Liquid Chromatography) compares the sample's retention time against a reference standard. Mass spectrometry confirms the molecular weight.
Purity Percentage
The percentage of the sample that is the target peptide versus impurities. Look for 99% or higher for research-grade peptides. Anything below 98% should raise questions.
Contaminants & Endotoxins
Checks for residual solvents, heavy metals, bacterial endotoxins, and microbial contamination. These should be below detectable limits or within acceptable ranges.
Testing Lab Information
The COA should name the independent third-party lab that performed the testing. Self-reported results from the seller without independent lab verification are a red flag.
Red Flags
- • No batch number or mismatched batch numbers
- • Purity below 98% with no explanation
- • No independent lab name or address
- • COA that looks photocopied or has missing sections
- • Results that seem too perfect with no methodology noted
- • Vendor refuses to provide a COA when asked
Why It Matters
Without a COA, there is no way to verify that what is in the vial matches the label. Under-dosed, contaminated, or misidentified products produce unreliable research and wasted resources. Always request and review the COA before starting any protocol, and cross-check the batch number on the vial against the document.
For laboratory research use only. Content is provided for research and educational purposes only and is not intended for human consumption, medical use, or diagnostic applications.