Clinical perspective, offered as context rather than as advice.

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: 16.6 minutes (consistent with semaglutide reference standard)
Peak purity: 98.5%
Related substances: 0.7% (single impurity at 10.4 minutes — likely a synthesis intermediate)
Mass spec: m/z 4113.5 (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.

Clinical perspective, offered as context rather than as advice.

I tested my certificates of analysis batch through Janoshik — 99.5% purity. That's within acceptable range for compounded peptides. Turnaround was 12 business days.

The test costs ~$137 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.

TrialNerd_Beth said:

I tested my certificates of analysis batch through Janoshik — 99.5% purity.

Second this. Posting only so the count is not one.

TrialNerd_Beth said:

I tested my certificates of analysis batch through Janoshik — 99.5% purity.

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: 99.3% average across orders (Janoshik verified)
Customer service: Responsive within 1 hours
Price: $147/month for semaglutide 1.7mg equivalent

Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful. Carry on.