An accessible introduction to peptides — what they are, how they differ from proteins, and why they matter in medicine and research.
Filed under basics, written for beginner, patient-consumer, journalist, evidence level A.
Not medically reviewed. Last updated 2026-04-15. Nothing here is medical advice.
Peptides are short chains of amino acids, typically between 2 and 50 residues in length, linked by peptide bonds. They are smaller than proteins but play critical roles in biological signaling, hormone regulation, immune function, and tissue repair.
While all peptides and proteins are made of amino acids, the key distinction is size:
Peptides serve as hormones, neurotransmitters, growth factors, and antimicrobial agents. The human body produces thousands of endogenous peptides that regulate virtually every physiological process.
Many approved medications are peptide-based. GLP-1 receptor agonists like semaglutide and liraglutide are among the most prescribed drugs globally. CGRP-targeting peptides treat migraine. Insulin analogs manage diabetes. These are rigorously tested, FDA-approved medicines — not "research chemicals."
It is critical to distinguish between:
1. **Approved peptide medicines** — FDA/EMA/Health Canada approved, manufactured under GMP
2. **Investigational peptides** — in clinical trials but not yet approved
3. **Research-use-only peptides** — sold for laboratory research, not for human use
4. **Unauthorized peptide products** — sold online without regulatory approval
This resource hub focuses on education, evidence, safety, and regulatory information. It does not provide dosing instructions, supplier recommendations, or guidance on using unauthorized products.
More guides: All guides, Safety centre, Peptide library.