What does 'third party tested' actually mean for a peptide seller?

It should mean an independent lab, not the seller, measured how pure the vial is and how much is in it, and published a report. In practice the phrase is used loosely. When we looked at the market's own reports, we found everything from reports linked to a named lab you can check, down to pages that just claim testing with no report at all. Ask which lab did it. Ask for the report number. Check whether that lab has a website where you can look up the report without going through the seller.

Educational use only. This database summarizes published research and is not medical advice. Where a dose appears it is a record of what a trial or clinic ran, or what people describe doing, with its source attached. Nothing here is a recommendation for personal use.

Part of buying, vendors, and lab testing. How to evaluate a seller's claims, certificates of analysis, and pricing.