What a peptide actually is — and why purity decides the result.

Amino acids link together in chains. Fifty or more and the chain is called a protein; fewer than fifty and it is a peptide. Insulin, oxytocin and glucagon are all peptides — molecules the body already uses to carry instructions between cells.

Because a peptide is short, its shape is predictable and its binding is narrow. It docks with one receptor family rather than reshaping cell chemistry wholesale. That specificity is exactly what makes peptides attractive in research: the question being asked stays tightly defined.

A peptide is defined entirely by the order of its amino acids. Swap one residue and the molecule can lose receptor affinity or gain unintended activity. There is no such thing as a 'close enough' sequence.

This is why identity testing sits alongside purity testing. High-performance liquid chromatography tells you how much of the vial is the target compound; mass spectrometry confirms the compound is the sequence it claims to be. A supplier reporting only one of the two is reporting half the story.

Peptides in solution degrade. Freeze-drying removes water under vacuum and leaves a stable powder that tolerates shipping and long storage. Vials arrive sealed under inert gas and should be kept refrigerated, away from light.

Once reconstituted with bacteriostatic water, stability is measured in weeks rather than years. Researchers should reconstitute only what a protocol requires and record the date on the vial.

A useful COA names the batch, the test date, the testing laboratory, and reports purity as a percentage with the chromatogram attached. It should also state endotoxin and residual solvent results.

If a document is undated, unbatched, or reuses the same chromatogram across products, it is marketing rather than analysis. Every DA Peptides batch carries its own document, and we will send it before purchase on request.