Dr.SleepRoch said:

They are not contradictory, they measure different things, and this is the single most common misreading of a certificate.

This is exactly what I could not find anywhere else. I will report back once I have actually tried it.

From the other side of the consultation, briefly.

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: 15.8 minutes (consistent with semaglutide reference standard)
Peak purity: 99.7%
Related substances: 0.6% (single impurity at 9.5 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.

Dr.NutriCornell said:

Third-party testing services for certificates of analysis besides Janoshik: Janoshik: Gold standard for peptide community, ~$158, 10-14 day turnaround…

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.NateNeph said:

The provenance questions are more useful than the numbers.

My vendor review relevant to certificates of analysis: ordered 6 times from my current compounder. Consistency has been excellent.

Shipping: 3-day with temperature monitor
Packaging: Professional, discreet, proper labeling with lot/batch numbers
Purity: 97.7% average across orders (Janoshik verified)
Customer service: Responsive within 1 hours
Price: $143/month for semaglutide 2.4mg equivalent

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