What Are Peptides?

Peptides are short chains of amino acids: the same building blocks that make up proteins, just fewer of them, strung together more loosely. A protein might contain hundreds or thousands of amino acids folded into a complex structure; a peptide is typically under 50, which gives it a simpler shape and lets it move through the body and interact with cells in more specific, targeted ways.

The body already produces thousands of peptides on its own. They act as signaling molecules: messengers that bind to specific receptors on cells and tell them to do something: release a hormone, begin repairing tissue, regulate digestion, or trigger any of dozens of other processes. Insulin is technically a peptide. So is oxytocin. What's changed in recent years is the ability to synthesize peptides in a lab, which has made a much wider range of them available for research, and increasingly, for people to use on their own.

Synthetic peptides are researched and used for a wide range of purposes, and most fall into a handful of broad categories: some are studied for tissue repair and recovery, others for their effect on the body's own growth hormone pathways, others for metabolic and weight-related effects, and others for cognitive or longevity-focused research. The categories below, and the individual compound pages within them, go into more detail on where a specific peptide fits and what it's generally used for.

Outside of a small number of FDA-approved pharmaceutical products, most peptides exist in a research context: sourcing, purity, and legal status vary a lot by compound and by where you live, and nothing on this site is medical advice. If you're already tracking a protocol, or planning to, that's what the PepLytics app is built for: logging doses, injection sites, and schedules privately on your own device.