How to Read a Certificate of Analysis (COA)

## Introduction

A Certificate of Analysis (COA) is your window into peptide quality. It's the document that tells you whether you're getting what you paid for — or expensive garbage.

Yet many researchers don't know how to read one properly or spot the red flags that indicate problems. This guide teaches you everything you need to evaluate a COA with confidence.

A Certificate of Analysis is an official document from a testing laboratory that details: COA Components:

• •Identity — Confirmation the compound is what it claims to be
• •Purity — Percentage of actual peptide vs impurities
• •Appearance — Physical characteristics
• •Testing methods — How the analysis was performed
• •Batch information — Lot numbers, dates, quantities

What to look for: FieldPurposeExample Peptide nameCompound identityBPC-157 Molecular formulaChemical compositionC62H98N16O22 Molecular weightSize verification1419.53 g/mol CAS numberUnique identifier137525-51-0 Batch/Lot numberTraceabilityBPC-2024-0142

High-Performance Liquid Chromatography (HPLC) is the gold standard for peptide purity testing. Understanding Purity Grades:

• •>99% — Pharmaceutical grade (exceptional)
• •98-99% — High-quality research grade (standard target)
• •95-98% — Acceptable for many applications
• •<95% — Concerning — significant impurities present

What a good HPLC report includes:

• •Purity percentage (should be 98%+ for research-grade)
• •Method details (column type, mobile phase, detection)
• •Retention time
• •Peak integration data or chromatogram

Mass spec confirms molecular identity by measuring the compound's mass-to-charge ratio. How it works:

1Compound ionized

2Ions sorted by mass-to-charge ratio

3Detector measures masses present

4Compare observed mass to expected mass

What you get:

• •Confirmation of correct molecular weight
• •Detection of closely related impurities
• •Identity verification

Describes the visual characteristics of the product: NormalConcerning White to off-white powderYellow or brown coloration Fluffy cake or powderLiquid present (should be dry) Consistent textureCrystalline when described as amorphous

Indicates how well the peptide dissolves:

• •Solvent used: Typically water or BAC water
• •Concentration achieved: Should fully dissolve
• •Clarity of solution: Should be clear, not cloudy

Peptides should be properly lyophilized (freeze-dried) with minimal moisture. Acceptable: Typically <5% water content Concerning: >10% moisture (degradation risk)

Here's what a proper COA looks like:

═══════════════════════════════════════════════
CERTIFICATE OF ANALYSIS
═══════════════════════════════════════════════

Product: BPC-157 (Pentadecapeptide)
Lot Number: BPC-2024-0142
Quantity: 5mg
Manufacturing Date: January 15, 2024
Expiry Date: January 15, 2026

───────────────────────────────────────────────
SPECIFICATIONS
───────────────────────────────────────────────

TEST               METHOD        SPEC          RESULT
─────────────────────────────────────────────────
Appearance         Visual        White powder   White powder ✓
Purity (HPLC)      RP-HPLC      ≥98.0%         98.7% ✓
Identity (MS)      ESI-MS       1419.5±1 Da    1419.51 Da ✓
Water Content      Karl Fisher   ≤8.0%          4.2% ✓
Acetate Content    IC           ≤15.0%         8.3% ✓
Endotoxin          LAL          <5 EU/mg       <1 EU/mg ✓

CONCLUSION: PASS - Meets all specifications

The COA's lot number should match what's on your product vial. Different lot = different product = COA may not apply

Look up the known molecular weight and CAS number for your peptide. They should match exactly. Verification Resources:

• •PubChem (pubchem.ncbi.nlm.nih.gov)
• •ChemSpider
• •Manufacturer datasheets

Legitimate labs will verify they tested a specific batch. If the listed lab has never heard of the vendor, that's a problem.

Look for ISO 17025 accreditation or similar credentials. Accredited labs follow standardized procedures.

Before purchasing, ask these questions: QuestionGood AnswerBad Answer "Can I see the COA for the specific batch I'm ordering?""Yes, here's lot #XYZ""We have COAs available" "Which lab performed the testing?"Named third-party lab"In-house" or "our supplier" "Can you provide the full HPLC chromatogram?"Yes, with image"The percentage is on the COA" "How often do you test batches?"Every batch / regular intervalsVague or no answer "What's your minimum purity specification?""98% or we don't sell it"No clear standard

Know the expected molecular weights and characteristics of peptides you research frequently: PeptideMolecular WeightCAS Number BPC-1571419.53137525-51-0 TB-5004963.4477591-33-4 Semaglutide4113.58910463-68-2 Ipamorelin711.85170851-70-4

Consistent, detailed COAs over time build trust. Marketing claims don't.

Reading a COA isn't difficult once you know what to look for.

Quality peptides cost more because proper testing costs money. A thorough COA is the proof that testing actually happened.