Understanding peptide purity: what your Certificate of Analysis actually means
FDA testing found that up to 40% of online peptides had incorrect dosages or undeclared ingredients. This is why understanding your vendor's COA matters. **What to look for:** - **HPLC Purity**: Should be 98%+ for injectable peptides. This measures what percentage of the sample is the actual peptide vs. degradation products or impurities. - **Net Peptide Content**: Different from purity. A vial labeled 5mg with 99% purity might only contain 3-4mg of active peptide. The rest is counter-ions, water, and acetate salts. Net peptide content of 60-80% is normal. - **Mass Spectrometry**: Confirms the peptide is actually the compound it claims to be. Without this, you could have a 99% pure sample... of the wrong peptide. - **Endotoxin Testing**: Critical for injectables. Bacterial endotoxins can cause fever, inflammation, and serious reactions. - **Amino Acid Analysis**: Confirms the correct sequence of amino acids. If your vendor doesn't provide at minimum HPLC purity and mass spec data from an independent third-party lab, consider that a red flag.
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This is important info. I learned the hard way that HPLC purity and net peptide content are different things. My first order was 99% pure but only 65% net peptide content — meaning my 5mg vial actually had ~3.25mg of active compound. Had to adjust my dosing calculations accordingly.
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so what was the res 2.75mg>? what kind of fillers are there? I had no idea about this.
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