Dr.SurgeonPGH said:Inter-laboratory variation comes from real methodological differences, not sloppiness: which reference standard was used and how it was itself…
I am more sceptical of certificates as a category than this thread is. The document tells you about a sample somebody chose to send, at a moment in time, and nothing about the vial in your hand. Independent purchase-and-test is a different quality of evidence and everything else is inference.
SarahChen_PharmD said:Two reports on the same product from two laboratories, four percentage points apart, and no method stated on either.
Third-party testing services for certificates of analysis besides Janoshik:
- Janoshik: Gold standard for peptide community, ~$140, 10-14 day turnaround
- Valitech: US-based, ISO 17025 accredited, ~$220
- Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
- ChemTox: Basic identity and purity testing, ~$110
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.
TrialTracker_MD said:I am more sceptical of certificates as a category than this thread is.
COA red flags for certificates of analysis — here's what to look for when reviewing a Certificate of Analysis:
- No HPLC data: If there's no chromatography graph, it's not a real COA
- Exact 100% purity: Suspicious — real testing always shows slight variation
- No batch number: Can't trace back to specific production
- No endotoxin testing: For injectables, this is essential
- Template looks like it was made in Word: Professional labs have standardized formats
I have seen fake COAs that are literally photoshopped. Always verify independently if possible.
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View ResultsOne thing that is still open after B12Beth’s answer:
Why two laboratories report different purity for the same batch, and which number to believe?
OP back with an update, since a thread like this is useless without one.
Purity and content being different measurements was the piece I was missing. The vial was overfilled and pure, which is a very different problem from the one I thought I had.