What peptides are, biologically
Peptides are short chains of amino acids, typically 2 to 50 long. Insulin is a peptide; so is oxytocin, glucagon, and a long list of signaling molecules the body produces naturally. Therapeutic peptides are synthetic copies (or rationally designed analogs) of these molecules, manufactured to act on specific receptors or pathways.
How peptide therapy works
Most peptides used in longevity and wellness practice fall into a small number of functional categories: tissue-repair peptides (BPC-157, TB-500), GH-axis peptides (tesamorelin, sermorelin), metabolic peptides (GLP-1 agonists, AOD-9604), sexual-function peptides (PT-141), longevity-research peptides (Epitalon), and mitochondrial peptides (MOTS-C). Each binds different receptors and produces different biological effects.
Categories at a glance
| Examples | FDA status | Typical use | |
|---|---|---|---|
| Tissue repair | BPC-157, TB-500 | Research-only / 503A | Soft tissue and joint recovery |
| GH-axis | Tesamorelin, sermorelin | Tesamorelin FDA-approved | Visceral fat, body composition |
| Metabolic | GLP-1 (semaglutide, tirzepatide), AOD-9604 | GLP-1 FDA-approved · AOD-9604 503A | Appetite, fat mobilization, glucose |
| Sexual function | PT-141 (Vyleesi) | FDA-approved (HSDD) | Sexual desire support |
| Mitochondrial | MOTS-C, Epitalon | Research-only | Cellular energy, aging biology |
How they are administered
Most clinical peptides are injected subcutaneously. Some are oral or topical. Self-injection technique is taught at the first visit and is similar to insulin or HRT injections.