newstart_MO 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:…

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

• Janoshik: Gold standard for peptide community, ~$132, 10-14 day turnaround
• Valitech: US-based, ISO 17025 accredited, ~$212
• Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
• ChemTox: Basic identity and purity testing, ~$122

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.

NicoleRaleigh said:

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

This is exactly what I could not find anywhere else.

newstart_MO 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:…

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

• Purity %: Should be >97%. Below 95% is concerning.
• Retention time: Should match reference standard for the peptide
• Related substances: Degradation products should be <2% total
• Single impurity: No individual impurity should exceed 1%

My last batch: 99.3% purity, 0.3% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.

fiona_glasgow 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 54 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: a post naming a supplier has been edited. Discuss suppliers in the review sections, not here. Carry on.