How to Read a Certificate of Analysis
A Certificate of Analysis (COA) is a document from a testing laboratory that reports the results of quality tests performed on a specific batch of product. For compounded peptides and injectables, a COA is your primary tool for verifying product quality and safety. Learn what each section means and what to look for.
Quick Summary
A legitimate COA should include: identity testing (HPLC), purity/assay results, endotoxin testing (LAL), sterility testing (USP <71>), appearance/pH checks, and clear lab identification. Click each section below to learn what these tests mean in plain language, what good results look like, and what red flags to watch for.
COA Evaluation Checklist
Use this checklist to evaluate a Certificate of Analysis for any compounded peptide or injectable product.
Product Identity (HPLC)
High-Performance Liquid Chromatography (HPLC) separates and identifies the molecules in your product. This test confirms the compound is what the label says it is — not a different peptide, not a degraded version, not contaminated with another substance.
Look For:
- ☐HPLC method clearly stated
- ☐Identity confirmed / passes
- ☐Retention time matches reference standard
- ☐Testing performed by ISO 17025 accredited lab
Watch For:
- ☐No identity testing performed
- ☐Only visual inspection (appearance test) listed
- ☐Lab name not provided or unverifiable
- ☐Identity test method not specified
Purity / Assay
Purity testing measures what percentage of the product is the intended active compound versus impurities, degradation products, or other contaminants. The assay value tells you the actual strength compared to what is labeled.
Look For:
- ☐Purity >95% (good), >98% (excellent)
- ☐Assay value within 90-110% of labeled strength
- ☐Related substances / impurities listed individually
- ☐Each impurity below accepted limits
Watch For:
- ☐Purity below 90%
- ☐No assay value reported
- ☐Large "unknown impurity" peaks
- ☐Assay significantly above 110% (may indicate concentration error)
Endotoxin Testing (LAL)
Endotoxins are toxic molecules from bacterial cell walls. Even if a product is sterile (no living bacteria), it can still contain endotoxins from bacteria that were present during manufacturing. The LAL (Limulus Amebocyte Lysate) test detects these. For injectable products, this is critical — endotoxin contamination can cause fever, shock, and organ damage.
Look For:
- ☐LAL test performed
- ☐Result: <5 EU/mL (standard limit for injectables)
- ☐Testing lab identified
- ☐Batch-specific results (not a generic pass)
Watch For:
- ☐No endotoxin testing performed
- ☐Result exceeds 5 EU/mL
- ☐Only states "passes" without specific value
- ☐Test performed on a different batch than your product
Sterility Testing
Sterility testing confirms that no bacteria, fungi, or other microorganisms are present in the product. For anything you inject, this is non-negotiable. USP <71> defines the standard methodology.
Look For:
- ☐USP <71> sterility testing performed
- ☐Result: No growth detected
- ☐14-day incubation period completed
- ☐Both aerobic and anaerobic media tested
Watch For:
- ☐No sterility testing performed
- ☐Sterility "assumed" based on manufacturing process
- ☐Testing period shorter than 14 days
- ☐Only one growth medium tested
Appearance / pH / Moisture
These basic quality checks verify the product looks and behaves as expected. Appearance should match what the compound is supposed to look like. pH must be within an acceptable range for injection. Moisture content for lyophilized products indicates proper freeze-drying.
Look For:
- ☐Clear, colorless solution (for reconstituted peptides)
- ☐pH within expected range (typically 4.0-8.0 for injectables)
- ☐Low moisture content for lyophilized products (<5%)
- ☐No particulate matter observed
Watch For:
- ☐Cloudy, discolored, or particulate-containing solution
- ☐pH outside expected range
- ☐High moisture content in lyophilized powder
- ☐Product appearance doesn't match expectations
Lab Information & Verification
A COA is only as trustworthy as the lab that produced it. Accredited labs follow standardized procedures and are regularly audited. You should be able to independently verify the lab exists and holds relevant accreditations.
Look For:
- ☐Lab name and address clearly stated
- ☐ISO 17025 or equivalent accreditation
- ☐Lab is independently searchable and verifiable
- ☐Contact information for the lab is provided
- ☐Batch/lot number on COA matches your product
Watch For:
- ☐No lab name provided
- ☐Lab cannot be found via internet search
- ☐No accreditation mentioned
- ☐COA appears to be a template with no batch-specific data
- ☐Batch number on COA doesn't match product label
Generated from Truth In Peptides COA Decoder — truthinpeptides.com/tools/coa-decoder
Important: A COA is a critical quality indicator, but it is not a guarantee. COAs can be fabricated, re-used across batches, or issued by unaccredited labs. Always verify the testing lab independently, confirm the batch/lot number matches your product, and use the Source Checker tool to evaluate your overall vendor.