Clinical perspective, offered as context rather than as advice.
My vendor review relevant to certificates of analysis: ordered 3 times from my current compounder. Consistency has been excellent.
Shipping: Next-day with cold pack
Packaging: Professional, discreet, proper labeling with lot/batch numbers
Purity: 98.0% average across orders (Janoshik verified)
Customer service: Responsive within 2 hours
Price: $120/month for tirzepatide 10mg equivalent
TirzTom said:Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members.
Third-party testing services for certificates of analysis besides Janoshik:
- Janoshik: Gold standard for peptide community, ~$128, 10-14 day turnaround
- Valitech: US-based, ISO 17025 accredited, ~$248
- Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
- ChemTox: Basic identity and purity testing, ~$118
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.
TirzTom said:Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members.
Thank you — that is the clearest version of this I have read, and I have read a lot of them.
Sigma-Aldrich — Research-Grade Standards
Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.
Shop Reference StandardsAdding the clinical framing, because it changes how the question reads.
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, 0.1% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.
Moderator note: the sourcing question belongs in the vendor section and has been split out. Tagging this one for the weekly digest.