Clinical perspective, offered as context rather than as advice.
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: 99.2% purity, 0.2% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.
HPLC_Greg said:I tested my certificates of analysis batch through Janoshik — 98.1% purity.
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.
HPLC_Greg said:I tested my certificates of analysis batch through Janoshik — 98.1% purity.
Bookmarking. The distinction being drawn above is the one nobody else makes. Sending this to two other people who asked me the same thing last week.
Janoshik Analytical — Independent Testing
Trusted third-party HPLC & mass spectrometry analysis. Verify peptide purity with the lab the community relies on. Independent. Accurate. Transparent.
Verify Your PeptidesGL Biochem (Shanghai) Ltd. — Direct Manufacturer
Est. 1998. The synthesis house behind the vials you send for testing. ISO 9001 and cGMP certified, 1,500+ staff, batch-specific COA with every order.
Browse GL BiochemAdding the clinical framing, because it changes how the question reads.
Third-party testing services for certificates of analysis besides Janoshik:
- Janoshik: Gold standard for peptide community, ~$141, 10-14 day turnaround
- Valitech: US-based, ISO 17025 accredited, ~$211
- Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
- ChemTox: Basic identity and purity testing, ~$101
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.
Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful. No action needed from anybody.