Peptide

A peptide is a short chain of amino acids — the same building blocks that make up proteins. The difference is size: proteins can be hundreds or thousands of amino acids long; peptides are typically fewer than fifty. The size matters for a practical reason. Most peptides are broken down in the gut before they reach the bloodstream. That's why the majority of research peptides are injected rather than swallowed — subcutaneous injection gets them into circulation intact. Your body makes peptides constantly. Insulin is a peptide. GLP-1 (the signal behind Ozempic) is a peptide. The drugs you already trust are built on this chemistry. What makes research peptides different is that they haven't been through the same approval process — the mechanism is real, the human evidence for specific compounds is often thin. The peptides covered on this site range from FDA-approved drugs (tesamorelin, bremelanotide) to PCAC-review candidates (BPC-157, MOTS-c) to compounds with no human trial data at all. The biology doesn't change. The regulatory and evidence status does — and that distinction is what drives the editorial framing here.