What is a COA for peptides?

A Certificate of Analysis (COA) is a document issued by a testing laboratory that reports the quality, purity, and identity of a specific batch of peptide. It provides objective evidence that the peptide is the correct compound and meets quality standards.

What HPLC purity should a research peptide have?

Research-grade peptides should have HPLC purity of 98% or higher. Premium peptides target 99% or above. A single dominant peak on the chromatogram with a clean baseline indicates high purity.

Shop by goal

Popular compounds

Research resources

Certificates of Analysis

How to Read a Certificate of Analysis (CoA)

Q: Why is third-party COA testing important?

In-house COAs are produced by the manufacturer, creating an inherent conflict of interest. Third-party COAs from independent laboratories like Janoshik Analytical or Freedom Diagnostics provide unbiased verification and are considered the gold standard.

A Certificate of Analysis (CoA) is a document issued by a testing laboratory that reports the quality, purity, and identity of a specific batch of compound. It's the single most important document for evaluating whether a research compound is suitable for use. Here's how to read one.

Why CoAs matter

Without a CoA, you're trusting a supplier's word. A legitimate CoA from an independent laboratory provides objective, quantitative evidence:

Identity

Whether the compound is what it's labelled as, not a substitute or impurity-laden batch.

Purity

Percentage of target molecule vs impurities, should be ≥98% for research-grade.

Contaminants

Endotoxins, residual solvents, heavy metals, tested and within safe limits.

Net content

The actual peptide mass per vial, counter-ions and moisture reduce the active dose.

Red flag: If a supplier cannot provide a CoA for a specific batch, or only provides a "generic" CoA without batch-specific data, that's a significant quality concern. Every batch should be independently tested.

Key sections of a CoA

01 Product identification The top of a CoA lists basic product information. Compound name , e.g. BPC-157, Semaglutide.

Batch / lot number , should match the label on your vial.

Molecular formula , the chemical formula.

Molecular weight , expected mass in Daltons (Da).

Sequence , the amino-acid sequence.

02 HPLC purity High-perf. liquid chromatography The gold standard for purity testing, separates the sample into its component molecules and measures what percentage is the target compound. Pass: ≥98% (premium ≥99%) How it works: sample pumped through a column; molecules elute at different times; UV detector measures area under each peak.

Reading the result: look for "HPLC Purity" or "Purity by HPLC" + a percentage. The chromatogram should show a single dominant peak on a clean baseline.

Warning sign: multiple large peaks or a noisy baseline indicates significant impurities or degradation.

03 Mass spectrometry MS / ESI-MS Confirms the compound's identity by measuring its molecular weight, your assurance that what's in the vial actually is what it claims to be. Pass: observed = theoretical ±1 Da Common methods: ESI-MS (electrospray ionisation) is most common; MALDI-TOF for larger peptides and proteins.

Reading the result: look for "MS" or "Mass Spec" with "Expected MW" and "Observed MW", they should closely match.

04 Appearance The physical form of the compound. Research-grade lyophilised compounds should be a white to off-white powder or fluffy cake . Discolouration (yellow, brown) can indicate degradation or impurities.

05 Solubility Reports whether the compound dissolves properly in standard solvents (water, bacteriostatic water, DMSO). A compound that won't dissolve may be degraded or incorrectly formulated.

06 Net peptide content A frequently overlooked but critical measurement. A vial labelled "5 mg" may contain 5 mg of total powder, but the actual peptide content can be less due to: Counter-ions , acetate or TFA salts used during synthesis add mass but aren't active peptide.

Moisture , even lyophilised compounds contain some residual water.

Net peptide content is expressed as a percentage (typically 70–85%). A 5 mg vial with 80% net content holds 4 mg of actual peptide.

07 Endotoxin testing LAL test Endotoxins are bacterial cell-wall fragments that can cause inflammatory responses. The Limulus Amebocyte Lysate test detects and quantifies them. Pass: <5 EU/mg Not always included: endotoxin testing adds cost. Its presence indicates a higher standard of QC.

08 Residual solvents GC test Peptide synthesis uses organic solvents (DMF, DCM, acetonitrile, TFA) that must be removed during purification. A residual-solvents test confirms these are within safe limits, typically via gas chromatography.

Third-party vs in-house testing

There's an important distinction between CoAs generated by the manufacturer and those issued by an independent laboratory.

Third-party (independent)

From labs like Janoshik Analytical or Freedom Diagnostics . Unbiased verification, the testing lab has no financial incentive in the result.

In-house

Produced by the same company that manufactured the compound. Useful, but involves an inherent conflict of interest.

New-U standard: Every New-U Research Compounds product is independently verified by both Janoshik Analytical and Freedom Diagnostics , two of the most respected independent testing laboratories in the field.

This independent-verification model is increasingly the editorial benchmark in the precision-diagnostics space - Wildlab Sky’s longevity-diagnostics overview, for example, points to third-party HPLC reports and named labs like Janoshik as the bar for analytical transparency in peptide research.

Quick checklist

When reviewing a CoA, verify:

Batch number matches your vial label.

HPLC purity is ≥98% (ideally ≥99%).

Mass spectrometry confirms correct molecular weight.

Appearance is white to off-white powder.

Independent third-party lab issued the CoA, not just the manufacturer.

Date of analysis is recent (within 12 months).

Once you've verified the CoA, the next steps are reconstituting the compound, confirming draw volumes with the reconstitution calculator, and following correct storage practices to maintain potency.

Frequently asked questions

What is a CoA for research compounds?

A Certificate of Analysis is a document issued by a testing laboratory that reports the quality, purity, and identity of a specific batch. It provides objective evidence the compound is correct and meets quality standards.

What HPLC purity should a research compound have?

Research-grade compounds should have HPLC purity of 98% or higher. Premium ones target 99%+. A single dominant peak on the chromatogram with a clean baseline indicates high purity.

Why is third-party CoA testing important?

In-house CoAs are produced by the manufacturer, creating a conflict of interest. Third-party CoAs from independent labs like Janoshik Analytical or Freedom Diagnostics provide unbiased verification, the gold standard.

Buy research peptides from New-U Research Compounds

Lab-verified by Janoshik Analytical (RP-HPLC + ESI-MS), sealed vials, discreet tracked worldwide shipping. For laboratory research use only — not for human consumption.

Premium research peptides at >99% HPLC-verified purity, third-party tested by Janoshik Analytical with a Certificate of Analysis on every lot. Shipped lab-direct, discreet and cold-chain, worldwide. For laboratory research use only.

Research use only (RUO). All products are sold strictly for laboratory and research purposes — not for human or veterinary consumption. Purchasers must be 21 or older.

Website & business operated by Hilxera Distribution Services LLC. Registered in Wyoming, ID: 2026-001928701.

Research use only — not for human consumption. All products are supplied strictly for laboratory research purposes.

How to Read a Certificate of Analysis (CoA)

Why CoAs matter

Identity

Purity

Contaminants

Net content

Key sections of a CoA

Third-party vs in-house testing

Third-party (independent)

In-house

Quick checklist

Frequently asked questions

Related reading

Independently verified research compounds

From the Lab - Peptides on LinkedIn & Facebook

Buy research peptides from New-U Research Compounds

Shop

Learn

Company

Support

Ways to Pay

Shop by Compound

Shop by Goal

Ships worldwide