Understanding Certificates of Analysis (COAs)

If you’re sourcing research peptides, a Certificate of Analysis is one of the most important documents you can request. Here’s how to read one and why it matters.

What is a Certificate of Analysis?

A Certificate of Analysis (COA) is a document issued by an independent laboratory that confirms the identity, purity, and quality of a specific batch of peptide. It’s essentially proof that what’s in the vial matches what’s on the label.

Why COAs matter

The peptide supply chain is global and varies enormously in quality. Without independent testing, there’s no way to verify:

• Whether the peptide is actually what it claims to be
• Whether it meets the stated purity level
• Whether it contains harmful contaminants or degradation products
  For researchers, unreliable compounds mean unreliable results. A COA removes the guesswork.

Key components of a COA

1. Peptide identity

The COA should confirm the peptide’s identity, usually through mass spectrometry (MS). This test measures the molecular weight of the compound and compares it to the expected value for that specific peptide sequence.
What to look for: The observed molecular weight should closely match the theoretical molecular weight (within acceptable instrument tolerance).

2. Purity (HPLC analysis)

High-Performance Liquid Chromatography (HPLC) is the gold standard for measuring peptide purity. It separates the peptide from any impurities and calculates the percentage of the target compound in the sample.
What to look for: Research-grade peptides should be 98% purity or higher. The HPLC chromatogram should show a single dominant peak with minimal secondary peaks.

3. Appearance

A simple visual inspection confirming the peptide’s physical form — typically described as a white to off-white lyophilised powder.

4. Batch/lot number

Every COA should reference a specific batch or lot number. This allows you to match the certificate to the exact product you received.

5. Testing date and laboratory

The COA should identify which laboratory performed the testing and when. Third-party testing (not the manufacturer’s own lab) provides the highest level of credibility.

Red flags to watch for

• No batch number — the COA may not correspond to your actual product
• In-house testing only — no independent verification
• Purity below 95% — not suitable for reliable research
• Missing mass spectrometry data — identity not confirmed
• Generic or templated COAs — may not be specific to the batch

How to request a COA from Eterna Labs

Every batch of Eterna Labs peptides is independently tested. To request a COA:

1. Email us with your order number and product name
2. We’ll send the relevant certificate for your specific batch

It’s that simple. We believe transparency is non-negotiable.

Eterna Labs supplies third-party tested, research-grade peptides across New Zealand. Browse our range at eternlabs.co.nz/shop.

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