How to read a Certificate of Analysis — complete guide

paige_pharma said:

Mass spectrometry confirmation for certificates of analysis: beyond HPLC purity, mass spec tells you the molecule's exact molecular weight.

Same pattern here, and in the same order. Nothing to add that would improve it.

josh_phd_bmore said:

Vendor quality matters when discussing certificates of analysis.

Second this. I had assumed I was the exception until I read this.

josh_phd_bmore said:

Vendor quality matters when discussing certificates of analysis.

COA red flags for certificates of analysis — here's what to look for when reviewing a Certificate of Analysis:

• No HPLC data: If there's no chromatography graph, it's not a real COA
• Exact 100% purity: Suspicious — real testing always shows slight variation
• No batch number: Can't trace back to specific production
• No endotoxin testing: For injectables, this is essential
• Template looks like it was made in Word: Professional labs have standardized formats

I have seen fake COAs that are literally photoshopped. Always verify independently if possible.

josh_phd_bmore said:

Vendor quality matters when discussing certificates of analysis.

Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members. Across 47 submitted tests:

• 75% tested at ≥98% purity
• 18% tested at 95-98% purity
• 7% tested at <95% purity (concerning)

The vendors with consistently high purity results are listed in the Vendor Directory. We update monthly based on new community submissions.

Moderator note: the sourcing question belongs in the vendor section and has been split out.