USP reference standards for peptide verification — anyone have experience?

NurseKim_ATL 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: 16.3 minutes (consistent with semaglutide reference standard)
Peak purity: 98.8%
Related substances: 0.6% (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.

dave_SLC said:

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

Bookmarking. The distinction being drawn above is the one nobody else makes. Taking it to my next appointment.

NurseKim_ATL said:

Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members.

Third-party testing services for certificates of analysis besides Janoshik:

• Janoshik: Gold standard for peptide community, ~$135, 10-14 day turnaround
• Valitech: US-based, ISO 17025 accredited, ~$215
• Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
• ChemTox: Basic identity and purity testing, ~$115

Janoshik is the community standard but any ISO-accredited analytical lab can verify peptide identity and purity. The key is independence — don't rely solely on the vendor's own testing.

lisa_labSD said:

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

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: 97.5% average across orders (Janoshik verified)
Customer service: Responsive within 4 hours
Price: $157/month for semaglutide 2.4mg equivalent

Moderator note: leaving this open. It is being argued well and the disagreement is the useful part. Report rather than reply if it drifts again.