Particulate matter testing — 6 month update

Dr.Martinez 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, ~$138, 10-14 day turnaround
• Valitech: US-based, ISO 17025 accredited, ~$218
• Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
• ChemTox: Basic identity and purity testing, ~$118

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.

rick_sfbay said:

Agreed, and mass spec answers a question purity does not: identity.

This is exactly what I could not find anywhere else.

Dr.Martinez said:

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

Mass spectrometry confirmation for certificates of analysis: beyond HPLC purity, mass spec tells you the molecule's exact molecular weight. This confirms identity — not just purity.

Why this matters: HPLC can show you a "pure" compound, but if it's pure of the WRONG compound, purity is meaningless. Mass spec at m/z 4113.58 Da confirms it's actually semaglutide. My Janoshik report includes both HPLC and mass spec.

If your testing provider only offers HPLC, consider upgrading to include mass spec for at least your first batch from a new vendor.

steph_laguna said:

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

I tested my certificates of analysis batch through Janoshik — 97.6% purity. That's within acceptable range for compounded peptides. Turnaround was 14 business days.

The test costs ~$132 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.

Moderator note: a couple of off-topic posts removed.