Dr.PeteFamMed said:

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

This is exactly what I could not find anywhere else.

rachel_ABQ said:

HPLC results interpretation for certificates of analysis: when you get your Janoshik report back, here's what the numbers mean: Purity %: Should be…

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

• Janoshik: Gold standard for peptide community, ~$139, 10-14 day turnaround
• Valitech: US-based, ISO 17025 accredited, ~$249
• Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
• ChemTox: Basic identity and purity testing, ~$119

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.

NauseaFreeNow said:

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

Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members. Across 58 submitted tests:

• 82% tested at ≥98% purity
• 12% tested at 95-98% purity
• 6% tested at <95% purity (concerning)

The vendors with consistently high purity results are listed in the Vendor Directory. We update monthly based on new community submissions.

Moderator note: reminder that nothing in this thread is medical advice, and that clinical claims need a source.