A practical guide for researchers in Colombia on what a COA is, what matters most, and how to spot red flags - without relying on marketing.
Important: Poly Biotech products are provided strictly for laboratory research use. Nothing in this article is medical advice. Products are not approved by INVIMA and are not intended for human or veterinary use.
What a COA is - and what it is not
A Certificate of Analysis (COA) is a lab report that documents test results for a specific batch (lot) of a compound. In peptide supply chains, it typically summarizes identity, purity, and sometimes contaminants or residual solvents.
A COA is not a regulatory approval, not a guarantee of suitability for any application, and not a substitute for proper research protocols. It is one piece of documentation that helps researchers evaluate quality and consistency across lots.
The 6 COA sections that matter most
- Header details - compound name, lot number, test date, and lab name
- Identity testing - often mass spectrometry (MS) or LC-MS, sometimes peptide mapping
- Purity testing - commonly HPLC with a chromatogram
- Assay / content - if included, confirms quantity or concentration context (varies by format)
- Impurities and contaminants - where available (endotoxin, heavy metals, bioburden, etc.)
- Traceability - signatures, methodology references, and clear linkage to the lot you received
Step 1 - Confirm the COA matches your exact lot
Before you interpret results, confirm the COA is actually for the batch you have. You want to see:
- Lot number on the COA that matches the lot on your packaging (or your supplier documentation)
- Compound name that is specific (avoid vague naming)
- Test date and report date that make sense for the supply timeline
- Lab identity (name, location, and ideally contact info or report verification methods)
If the COA does not clearly match the lot, treat it as marketing - not documentation.
Step 2 - Understand purity results (HPLC) without overthinking it
HPLC (High-Performance Liquid Chromatography) is one of the most common methods used to estimate peptide purity. The COA may list purity as a percentage, and may include a chromatogram (a graph with peaks).
In simple terms: a cleaner sample generally shows a dominant main peak with fewer or smaller secondary peaks. However, purity numbers depend on method, column type, gradient, and detection wavelength - so comparisons only really make sense when methods are similar.
Practical rule: Use COAs to evaluate consistency across lots and to catch obvious problems - not to chase perfect purity numbers in isolation.
If you want a deeper overview of verification methods (HPLC, purity, and lab practices), see: How Research-Grade Peptides Are Verified (HPLC, Purity, COAs).
Step 3 - Identity testing (MS, LC-MS) and why it matters
Identity testing aims to confirm you are analyzing the intended compound - not a misidentified or substituted material. COAs may reference MS (mass spectrometry), LC-MS, or other identity confirmation.
Researchers commonly look for a result that matches the expected molecular weight or signature for the peptide. If identity testing is missing entirely, that is a meaningful gap in documentation.
For general compound reference, PubChem can be useful for identity context: PubChem (NIH).
Step 4 - Impurities, contaminants, and what is often missing
Depending on the supplier and intended research context, a COA may include additional testing such as:
- Residual solvents
- Heavy metals
- Bioburden or microbial limits
- Endotoxin (LAL testing)
- Moisture content (Karl Fischer) or related stability indicators
Many COAs in the market include only HPLC purity and an identity line item. That does not automatically mean a product is "bad" - it means the documentation is incomplete and should be interpreted accordingly.
Step 5 - Common COA red flags
- No lot number, or a lot number that does not match your batch
- Generic templates with no lab identifiers or signatures
- Missing methods (no mention of HPLC conditions or identity method)
- Suspicious formatting (pixelated screenshots, inconsistent fonts, or obvious edits)
- Purity claims that are not supported by a chromatogram or methodology reference
- COAs that do not reference the supplier or cannot be verified in any way
How Poly Biotech handles COAs (including BPC-157)
Poly Biotech maintains lot-level documentation as part of our research supply process. For some products, we have COAs issued in our name for specific lots. For example, we currently have a COA available for BPC-157.
If you are a researcher or clinic customer and need documentation for your records, you can request the relevant COA for the lot you received. The correct COA should match your lot number and include the lab and method details.
COA request note: When requesting documentation, include your order number and the product lot number (if available). You can contact us here: Contact.
Related reading: Peptide Pricing in Colombia and Knowledge Center.
FAQ
Does a higher purity percentage always mean better?
Not always. Purity percentages are method-dependent. A COA is most useful for comparing lots tested under similar conditions and for identifying obvious problems.
Should every COA include a chromatogram?
Ideally yes for HPLC-based purity claims, but in practice many do not. If a chromatogram is missing, look for method details and treat the purity claim cautiously.
What is the single biggest mistake people make with COAs?
Not matching the COA to the exact lot received. If the COA does not match your lot, it is not reliable documentation for your material.
Related products (research use only): BPC-157 | Research Peptides | Legal and Medical Disclaimer