Dr.GutHealth said:Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members.
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: 99.6% purity, 0.2% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.
One thing that is still open after Dr.GutHealth’s answer:
What would you measure differently if you were starting again?
quinn_sf 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, ~$122, 10-14 day turnaround
- Valitech: US-based, ISO 17025 accredited, ~$232
- Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
- ChemTox: Basic identity and purity testing, ~$112
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.
Sigma-Aldrich — Research-Grade Standards
Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.
Shop Reference Standardsquinn_sf said:HPLC results interpretation for certificates of analysis: when you get your Janoshik report back, here's what the numbers mean: Purity %: Should be…
Agreed, with the usual condition: that holds for the average and this board is a collection of individuals. A population claim and a personal prediction are different things and get quoted interchangeably.
quinn_sf said:HPLC results interpretation for certificates of analysis: when you get your Janoshik report back, here's what the numbers mean: Purity %: Should be…
That reframing is the part I needed.