Inter-lab variability in peptide testing — July 2024

Clinical perspective, offered as context rather than as advice.

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.

TirzTom said:

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…

Bookmarking. The distinction being drawn above is the one nobody else makes.

Clinical perspective, offered as context rather than as advice.

My vendor review relevant to certificates of analysis: ordered 5 times from my current compounder. Consistency has been excellent.

Shipping: Same-day local pickup
Packaging: Professional, discreet, proper labeling with lot/batch numbers
Purity: 97.2% average across orders (Janoshik verified)
Customer service: Responsive within 6 hours
Price: $146/month for semaglutide 2.4mg equivalent

Dr.GastroMayo said:

My vendor review relevant to certificates of analysis: ordered 5 times from my current compounder.

This is my experience too, for whatever a second data point is worth. I had assumed I was the exception until I read this.

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