Research Standards Series
How to Read a Certificate of Analysis (COA) for Research Peptides
Understanding the document that separates premium research compounds from questionable sources — and why it matters for every protocol.
When you source research peptides, the Certificate of Analysis — commonly called a COA — is not just a formality. It is the foundational document that establishes whether a compound is what it claims to be. Yet many researchers receive a COA with their order, glance at it, and file it away without understanding what they're looking at.
That's a missed opportunity — and a potential research risk. Learning to read a COA fluently is one of the most valuable skills a peptide researcher can develop. This guide breaks down every section of a standard COA so you can evaluate any research peptide with confidence.
What Is a Certificate of Analysis?
A Certificate of Analysis is a third-party laboratory document that reports the results of testing performed on a specific batch of a compound. For research peptides, a proper COA should confirm identity, purity, and potency — the three pillars of compound quality.
The critical word here is third-party. A COA issued by the manufacturer themselves carries limited credibility — it's essentially self-grading. A COA from an independent, accredited laboratory that has no financial relationship with the supplier is the gold standard. At My Freedom Peptides, every product is tested through Freedom Diagnostics Testing, an independent third-party lab, before it ever reaches a researcher.
The Five Core Sections of a COA
1. Product Identification
The top of every legitimate COA should clearly state: the compound name (both common name and chemical/IUPAC name), the CAS registry number (a unique identifier assigned to every chemical substance), the lot or batch number, and the date of analysis.
What to verify: Cross-reference the CAS number independently. For example, Semaglutide should list CAS 910463-68-2. Tirzepatide should list CAS 2023788-19-2. Retatrutide (LY3437943) should list CAS 2381272-15-5. If the CAS number doesn't match the compound name, stop there.
2. Purity Results (HPLC)
Purity is typically measured via High-Performance Liquid Chromatography (HPLC). This technique separates the compound from impurities and reports a purity percentage based on area-under-the-curve analysis of the resulting chromatogram.
For research-grade peptides, a purity of 98%+ is considered premium quality. Many lower-tier suppliers sell peptides at 95–96% purity, which may seem close but introduces a meaningful amount of unknown impurities into any research protocol.
What to look for: The COA should include the actual chromatogram image or data table, not just a stated number. A legitimate HPLC report shows retention time, peak area, and the calculated percentage. If you're only given a percentage with no supporting data, be skeptical.
3. Identity Confirmation (Mass Spectrometry)
Mass Spectrometry (MS) confirms that the compound is exactly what it claims to be by measuring the molecular weight of the substance. Every peptide has a unique molecular formula and therefore a unique mass — Semaglutide has a molecular weight of 4,113.58 Da, for instance. Mass spec identifies the compound with a precision that HPLC alone cannot provide.
What to look for: The reported molecular ion (M+H or M+nH peaks in the spectrum) should match the theoretical molecular weight of the compound. A COA that includes HPLC purity data but no mass spec confirmation is incomplete for high-value research peptides.
4. Residual Solvents & Moisture Content
During peptide synthesis and purification, solvents such as acetonitrile, methanol, and TFA (trifluoroacetic acid) are commonly used. A quality COA will include residual solvent testing, confirming that these solvents have been removed to acceptable levels.
Moisture content (often measured via Karl Fischer titration) is also significant: lyophilized peptides with high moisture content degrade faster and may deliver an inaccurate dose per milligram. A moisture content below 8% is generally considered acceptable for lyophilized research peptides.
5. Laboratory Credentials & Signature
A legitimate COA is signed or stamped by a qualified analyst and includes the laboratory's name, address, accreditation number (look for ISO/IEC 17025 accreditation for the highest standard), and contact information. This makes the document traceable and verifiable.
Red flag: A COA with no laboratory name, no analyst signature, or a lab name that doesn't appear in any accreditation database should be treated with extreme caution.
Common COA Red Flags to Watch For
- ⚠ No lot number or batch tracking — without batch traceability, there's no way to verify when the compound was tested or whether your vial came from a tested batch.
- ⚠ Purity stated as ">99%" with no data — a suspiciously round or high number without chromatogram data is a marketing claim, not analytical verification.
- ⚠ Generic COA across multiple products — if the lab name, date, and layout are identical across ten different compounds, the document may be fabricated or recycled.
- ⚠ Testing date predates the supplier's founding — cross-check when the lab report was issued versus the company's launch date. Discrepancies can indicate falsified documents.
- ⚠ HPLC purity only, no mass spec — for complex peptides like Retatrutide or Tirzepatide, mass spectrometry confirmation is non-negotiable. HPLC alone cannot confirm the amino acid sequence is correct.
Why COA Literacy Matters for Research Integrity
Research compounds with incorrect identity or substandard purity don't just produce unreliable data — they undermine entire bodies of research. When a study uses an impure peptide and reports unexpected results, those results may reflect the impurity rather than the compound itself. This problem compounds across the research community when others build on that flawed work.
COA literacy is, at its core, about research integrity. The time it takes to verify a COA properly — five to ten minutes — is among the most valuable investments a researcher can make before beginning any protocol.
Our Commitment to Transparency
Every batch sold through My Freedom Peptides comes with a full, independently verified COA from Freedom Diagnostics Testing. Identity confirmation via mass spec. HPLC purity. Lot-traceable documentation. Always accessible, never hidden.
Because researchers deserve to know exactly what they're working with.
The Bottom Line
A Certificate of Analysis is only as valuable as your ability to read it. Check the product identification and CAS number. Scrutinize the HPLC data — not just the stated percentage. Confirm mass spectrometry results are present for complex peptides. Verify the laboratory credentials. And be alert to the red flags that indicate shortcuts or falsification.
The standard exists to protect the integrity of research. When you know how to read a COA, you hold the supplier accountable — and you put better science into the world.
Frequently Asked Questions
What is a certificate of analysis (CoA) and what information should it contain?
A CoA is a quality document issued by the manufacturer or a third-party testing lab confirming a compound's identity, purity, and physical characteristics. For research peptides, it should include HPLC purity (%), mass spectrometry molecular weight confirmation, lot number, manufacturing date, and the testing laboratory's name and credentials.
What HPLC purity threshold is acceptable for research-grade peptides?
Most research protocols specify ≥98% purity by HPLC as the minimum acceptable standard. Peptides below this threshold may contain truncated sequences, protecting group remnants, or oxidized variants that can confound experimental results.
How can I verify a CoA is authentic and not fabricated?
Cross-reference the named testing laboratory's address and accreditation status online. Legitimate CoAs include chromatogram traces with retention time data, a mass spectrum peak matching the theoretical MW, and a signed declaration by a QC analyst. Generic or template-only documents without raw data are unreliable.
What does it mean when a peptide CoA shows multiple HPLC peaks?
Multiple peaks indicate the presence of impurities — which could be truncated synthesis byproducts, oxidized variants (e.g., methionine sulfoxide), or aggregates. The main peak area percentage is the reported purity; peaks outside the main signal represent contaminant fractions.
Should CoA testing be performed by the manufacturer or an independent lab?
Independent third-party testing is the gold standard because it eliminates conflicts of interest. Researchers should prefer suppliers who provide CoAs from accredited external labs rather than in-house testing alone, as this provides unbiased purity and identity confirmation.
For research use only. Not intended for human consumption.
For research use only. Not intended for human consumption. These statements have not been evaluated by the Food and Drug Administration.