Dr.EM_Chicago said:They are not contradictory, they measure different things, and this is the single most common misreading of a certificate.
Genuinely useful, thank you. I had the facts and not the framework. I will report back once I have actually tried it.
From the other side of the consultation, briefly.
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.
Dr.SleepRoch said:Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members.
My HPLC chromatogram analysis for certificates of analysis — I sent my batch to Janoshik and here's what the results showed:
Main peak retention time: 15.5 minutes (consistent with semaglutide reference standard)
Peak purity: 99.7%
Related substances: 0.4% (single impurity at 9.1 minutes — likely a synthesis intermediate)
Mass spec: m/z 4113.6 (matches expected molecular weight)
This is a clean result. The mass spec confirmation is particularly important — it proves the molecule is actually semaglutide and not a substitution.
Sigma-Aldrich — Research-Grade Standards
Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.
Shop Reference StandardsPurityPaulOR said:I have a certificate reporting 99.2% purity and 6.1mg content on a vial sold as 5mg, and I cannot work out whether those two numbers are consistent or…
My vendor review relevant to certificates of analysis: ordered 4 times from my current compounder. Consistency has been excellent.
Shipping: 2-day priority with gel ice
Packaging: Professional, discreet, proper labeling with lot/batch numbers
Purity: 98.1% average across orders (Janoshik verified)
Customer service: Responsive within 4 hours
Price: $137/month for tirzepatide 10mg equivalent