How to read a peptide Certificate of Analysis (COA)

For research purposes only. Not for human consumption. 18+. UK only.

Definition

A peptide Certificate of Analysis (COA) is a laboratory document confirming the identity, purity, and quality of a specific batch of synthesised peptide. It is issued by the laboratory that performed the analysis and references a unique batch number. Reputable UK research-peptide suppliers publish a COA per batch and link to it from the product page or vial.

This guide explains how to read one — what each section means, what to verify before purchase, and how to spot a marketing document dressed up as a COA. Written for researchers and the UK research community evaluating supplier quality.

Why COAs matter

A COA is the only practical way for a buyer to verify what is actually in the vial. Two compounds with the same name on the label can differ significantly in purity, identity, and stability. Without an independent test result tied to a specific batch, you are taking the supplier's word for it.

Independent laboratory testing of peptide products has historically found:

• Variation in actual purity versus claimed purity, sometimes by tens of percentage points
• Misidentified compounds — the wrong peptide entirely, or a different sequence variant
• Detectable residual solvents from incomplete purification

A COA from an independent third-party laboratory, tied to the batch you are buying, is the standard the research community relies on to filter for credible suppliers.

The structure of a real COA

A complete COA includes the following sections. Use this as a checklist when you receive one.

1. Header — supplier and laboratory identification

The COA should identify:

• The supplier of the peptide (e.g., BioHack London Ltd)
• The independent laboratory that performed the testing (named, with contact details or website)
• The product name (e.g., "BPC-157 Vial 5 mg")
• The batch / lot number — a unique identifier for this manufacturing batch
• The test date — when the analysis was performed

If the document doesn't name an independent laboratory, it isn't a third-party COA — it's a manufacturer's self-declaration. That distinction matters.

2. Purity result via HPLC

HPLC (High-Performance Liquid Chromatography) separates the components of a sample by passing them through a column under high pressure. A detector measures what comes off the column at each time interval, producing a chromatogram — a graph with peaks representing different molecules.

For a research peptide, the COA should include:

• A purity percentage — the proportion of the total signal attributable to the target peptide. Research-grade compounds typically target ≥99%.
• The chromatogram itself — a visual showing the main peptide peak and any impurity peaks.
• The method conditions — column type, mobile phase, gradient, detection wavelength. This documents the test was reproducible.

A single number ("99.5% pure") without a chromatogram is less reliable than a number plus a chromatogram. The chromatogram lets you see the size and number of impurity peaks — a clean run with one dominant peak is qualitatively different from one with several smaller peaks summing to "99%."

3. Identity confirmation via mass spectrometry

Mass spectrometry (MS) measures the mass-to-charge ratio of ionised molecules. For a peptide, this confirms identity by checking that the measured molecular weight matches the calculated molecular weight from the amino-acid sequence.

The COA should include:

• The expected molecular weight for the target peptide (calculated from sequence)
• The measured molecular weight from the MS analysis
• A match confirmation — typically the measured value is within 0.1 Da of expected

If the MS result is missing or significantly off, the compound may be misidentified. This is rare but it has happened in the category.

4. Additional analyses (optional but useful)

Higher-quality COAs may also include:

• Water content (Karl Fischer titration) — relevant for shelf life
• Residual solvent analysis — particularly trifluoroacetic acid (TFA), a common synthesis residue
• Peptide content (amino-acid analysis) — confirms the quantity of peptide in the vial as opposed to just the purity of what's there
• Endotoxin testing — relevant for some research applications

These aren't required for every research-grade product, but their presence indicates a more rigorous testing regime.

5. Signature and dating

The COA should be signed by the laboratory analyst who ran the tests, dated, and on the testing laboratory's letterhead. Anonymous, unsigned, or undated COAs are weaker evidence.

What to verify before purchase

When you've found the COA for the product you're considering, three checks:

1. Does the batch number on the COA match the batch number you'll receive? Reputable suppliers ship the vial with a batch number that matches the published COA. Some put a QR code on the vial linking to that batch's COA — this is the gold standard.

2. Is the purity result ≥99%? Research-grade compounds typically target this. Lower purity might still be useful for some research applications but should be priced accordingly and disclosed clearly.

3. Was the test performed in the past 12 months? A COA from three years ago doesn't tell you anything about the batch shipping today. The test date should be recent enough to be relevant to the inventory currently shipping.

Red flags — when a "COA" isn't really a COA

Several patterns distinguish a credible COA from a marketing document. If you see any of these, treat the document with skepticism:

• No batch number referenced. Generic certificates not tied to a specific batch are not COAs.
• No independent laboratory named. Self-issued by the supplier or manufacturer with no third-party verification.
• No chromatogram, only a single percentage number. The visual matters; the number alone is less verifiable.
• No mass spectrometry result. Identity confirmation is non-negotiable for serious research.
• Test date older than 12 months. Stale data does not represent current inventory.
• No method conditions specified. Reproducibility cannot be verified.
• Unsigned, undated, or no laboratory letterhead. Reduces credibility.
• Cannot be downloaded from the supplier's site before purchase. Suppliers who only "share the COA after purchase" are gating verification past the buying decision — that's by design, not by accident.

How BioHack London publishes COAs

(Section to be tailored by author — sample copy below for reference.)

Every BioHack London peptide vial ships with a QR code linking to the Certificate of Analysis for that specific batch. The COA includes HPLC purity verification (with chromatogram and method conditions), mass spectrometry molecular weight confirmation, and is signed and dated by the independent third-party testing laboratory. Buyers can also access the COA before purchase via the product page on biohacklondon.com.

This is the bar BioHack London operates to. Many UK research-peptide suppliers do not.

Frequently Asked Questions

What does HPLC stand for, and what does it measure?

HPLC stands for High-Performance Liquid Chromatography. It separates the components of a peptide sample so the proportion of target peptide versus impurities can be measured. The output is a chromatogram showing peaks; the area under the target peak as a percentage of total area is reported as purity.

What's the minimum purity I should expect from a UK research-peptide supplier?

Most reputable UK suppliers target ≥99% purity for research-grade compounds. Some specialty applications may use lower purity by design, but 99% is the conventional minimum.

Why does mass spectrometry matter if HPLC already shows purity?

HPLC tells you what proportion of your sample is the target peptide; it does not tell you what the peptide actually is. Mass spectrometry confirms the molecular weight matches the expected value, which means you have the peptide you ordered — not a different peptide of similar purity.

What's the difference between a Certificate of Analysis and a Certificate of Conformity?

A Certificate of Analysis reports the actual measured results from testing a specific batch — purity, identity, additional analyses. A Certificate of Conformity is a statement that a batch meets a specification, without necessarily disclosing the underlying test data. COAs are the more useful document for the research buyer.

Can a COA be faked?

Yes, in principle. The defences are: independent third-party testing (the laboratory has no incentive to misrepresent results), batch-specific COAs that match the batch number on the vial, and supplier transparency that allows public scrutiny. Suppliers who publish COAs openly are signalling their willingness to be checked.

What should I do if a supplier won't share a COA before purchase?

Look elsewhere. The COA is the basis on which a research buyer can evaluate quality. A supplier who gates this past the purchase decision is not operating to research-community standards.

Are COA results different for different production batches of the same peptide?

Yes — slightly. Each batch is independently produced and tested, so HPLC purity and minor impurity profiles vary marginally between batches. This is normal and reflects honest reporting. The bar is consistency in meeting the ≥99% standard, not identical numbers every time.

What to do next

Three actions if you're evaluating a COA right now:

1. Locate the batch number on the document and confirm it matches the batch you'll receive.
2. Confirm an independent third-party laboratory is named — not just the supplier or manufacturer.
3. Check HPLC purity and mass spectrometry molecular weight are both present, with chromatograms and method conditions.

If all three check out, you're looking at a credible COA. If any one is missing, ask the supplier to clarify. Their response (or lack of one) tells you what you need to know about their operation.

For deeper background on what "independently verified" actually requires — and the difference between tested and verified — see our reference guide on independently verified UK research peptides.

About BioHack London. BioHack London is a UK-based supplier of premium research peptides. Every batch is independently HPLC and mass-spectrometry tested by a third-party laboratory and published as a Certificate of Analysis, accessible before purchase and via QR code on the vial. UK-made, UK-delivered. For research purposes only. Not for human consumption. 18+.

Disclaimer. This article describes the technical content of a peptide Certificate of Analysis for the UK research community. It does not constitute medical, legal, or regulatory advice. The compounds discussed are sold and intended for in vitro laboratory research use only, not for human or veterinary use, and not for diagnosis, treatment, cure, or prevention of any disease.

References (selected).

• Snyder, L.R., Kirkland, J.J., Dolan, J.W. (2010). Introduction to Modern Liquid Chromatography, 3rd Edition. Wiley.
• de Hoffmann, E., Stroobant, V. (2007). Mass Spectrometry: Principles and Applications, 3rd Edition. Wiley.
• ICH Q3C (R8) Guideline on Residual Solvents — relevant for understanding TFA testing and limits.

Compliance review pass (per CLAUDE.md Rule 5)

• No health/medical/performance claims. Verified — article is purely about quality/testing methodology, no claimed effects.
• Researcher audience framing throughout. Verified — addresses "research buyers," "the research community," "researchers evaluating supplier quality."
• Compound names — only one mentioned (BPC-157, in passing reference). Compound names allowed in editorial content.
• Visual vocabulary — N/A (text article). Hero image brief (when commissioned): editorial flat-lay of a chromatogram printout + brass scientific instrument on dark wood, no human elements.
• Disclaimer block present.
• 18+ + UK only stated.
• No personal-use language, no outcome words. Verified.

Reviewer: [to be signed off by BadHunga before publish]