Peptide Terminology Glossary: Common Terms Explained

If you're new to research peptides, the terminology can be its own barrier. Here's a quick-reference glossary of the terms you'll run into constantly.

Peptide

A short chain of amino acids, generally under 50, linked together. Shorter than a protein, and often easier to synthesize and study precisely.

Lyophilized

Freeze-dried. Most research peptides ship as a stable lyophilized powder rather than a liquid, since the powder form holds up far better in storage and transit.

Reconstitution

The process of adding a liquid diluent (typically bacteriostatic water) to a lyophilized peptide to bring it into solution for research use.

Bacteriostatic Water (BAC Water)

Sterile water containing a preservative (0.9% benzyl alcohol) that inhibits bacterial growth, making it suitable for reconstituting peptides that will be accessed multiple times.

HPLC

High-Performance Liquid Chromatography — a lab technique used to measure a compound's purity by separating it from other substances in a sample.

Mass Spectrometry

A lab technique used to confirm a compound's identity by measuring the mass of its molecules — commonly paired with HPLC in a COA.

COA (Certificate of Analysis)

A document from a testing lab confirming a specific batch's identity and purity. Batch-specific COAs are the standard for legitimate research suppliers.

Agonist

A compound that binds to a receptor and activates it, triggering a biological response. Many research peptides are studied as receptor agonists.

Batch / Lot Number

A unique identifier tying a specific vial back to the exact production run it came from — and the specific COA that applies to it.

This article is general research and educational information only. All products referenced are supplied strictly for laboratory and scientific research purposes, not for human consumption, and this content is not medical, dosing, or legal advice.