Dr.ObesityMed said:

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…

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: 14.6 minutes (consistent with semaglutide reference standard)
Peak purity: 99.6%
Related substances: 0.4% (single impurity at 8.7 minutes — likely a synthesis intermediate)
Mass spec: m/z 4113.58 (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.

SarahChen_PharmD said:

One addition: an unstated method makes a report close to uninterpretable.

That reframing is the part I needed. Adding it to my notes with a link back to this thread.

Dr.ObesityMed said:

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…

I tested my certificates of analysis batch through Janoshik — 99.2% purity. That's within acceptable range for compounded peptides. Turnaround was 8 business days.

The test costs ~$131 but gives you actual HPLC chromatography data plus mass spec confirmation. For the peace of mind alone, it's worth every penny. I test every new batch from a new vendor.

dan_philly 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: 99.5% average across orders (Janoshik verified)
Customer service: Responsive within 4 hours
Price: $141/month for semaglutide 1.7mg equivalent

Moderator note: reminder that nothing in this thread is medical advice, and that clinical claims need a source. Report rather than reply if it drifts again.