Clinical perspective, offered as context rather than as advice.

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

• Janoshik: Gold standard for peptide community, ~$128, 10-14 day turnaround
• Valitech: US-based, ISO 17025 accredited, ~$248
• Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
• ChemTox: Basic identity and purity testing, ~$128

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.

HPLC_Greg said:

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

This is exactly what I could not find anywhere else. Printing the relevant bit and taking it with me.

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: 14.2 minutes (consistent with semaglutide reference standard)
Peak purity: 99.3%
Related substances: 0.6% (single impurity at 8.1 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.

KevinCompounds said:

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:…

Can confirm. Same sequence, different timescale. The detail I would add is minor and it is already implied above.

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.