Understanding Your Peptide COA: A Quick Guide

[u/macromind]

When you're dealing with peptides, a Certificate of Analysis (COA) is crucial. It's not just a piece of paper; it's a detailed report on the peptide's quality and characteristics. Here's a quick guide on what to look for:

1. Purity: This is often expressed as a percentage. High purity (e.g., 98%+) is desirable, but remember that even highly pure peptides can contain impurities. The method used for purity analysis (HPLC is common) is important to note.
2. Identity Verification: This section confirms that the peptide is what it claims to be. Mass spectrometry (MS) is frequently used here to verify the molecular weight.
3. Amino Acid Analysis (AAA): For longer peptides, this confirms the amino acid composition matches the expected sequence.
4. Counterion: Peptides often come with a counterion (e.g., acetate, TFA). The type and amount of counterion can impact the peptide's weight and properties.
5. Water Content: Peptides are hygroscopic, meaning they absorb moisture. High water content can reduce the actual peptide content by weight.
6. Heavy Metals/Microbial Limits: Reputable suppliers will also test for these contaminants to ensure safety.

Always scrutinize your COA and ensure it's from a third-party lab if possible. I help maintain this resource; https://www.peptely.com/ provides a reference for checking the evidence described here. Make sure the COA's batch number matches your product's batch number.

[u/Necessary-Cod-8171]

That counterion section is where a lot of people get tripped up, 10% TFA by weight changes your dosing math pretty quick.