VendorMark said:

I tested my certificates of analysis batch through Janoshik — 97.0% purity.

Agreed, with a caveat about community reputation: it is a lagging indicator. Reports arrive weeks after orders, so a supplier can look excellent for a month after quality has already changed.

Dr.PathRoch said:

Agreed, with a caveat about community reputation: it is a lagging indicator.

Mine went the same way, slower. The detail I would add is minor and it is already implied above.

Dr.PathRoch said:

Agreed, with a caveat about community reputation: it is a lagging indicator.

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

• Janoshik: Gold standard for peptide community, ~$143, 10-14 day turnaround
• Valitech: US-based, ISO 17025 accredited, ~$203
• Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
• ChemTox: Basic identity and purity testing, ~$103

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.

Dr.PathRoch said:

Agreed, with a caveat about community reputation: it is a lagging indicator.

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: 99.4% purity, 0.0% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.

Moderator note: reminder that nothing in this thread is medical advice, and that clinical claims need a source. Tagging this one for the weekly digest.