⚠ Fake COAs — looking for input

Dr.RaviCardio said:

The provenance questions are more useful than the numbers.

I am more sceptical of certificates as a category than this thread is. The document tells you about a sample somebody chose to send, at a moment in time, and nothing about the vial in your hand. Independent purchase-and-test is a different quality of evidence and everything else is inference.

mark_tokyo said:

Two reports on the same product from two laboratories, four percentage points apart, and no method stated on either.

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: 16.3 minutes (consistent with semaglutide reference standard)
Peak purity: 98.2%
Related substances: 0.7% (single impurity at 10.2 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.

LarryQC_SD said:

I am more sceptical of certificates as a category than this thread is.

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: 99.1% average across orders (Janoshik verified)
Customer service: Responsive within 4 hours
Price: $137/month for semaglutide 1.7mg equivalent

Following on from pam_columbus — and this may be the naive question:

Why two laboratories report different purity for the same batch, and which number to believe?

Reporting back.

Purity and content being different measurements was the piece I was missing. The vial was overfilled and pure, which is a very different problem from the one I thought I had.