EP 011:10

What is a peptide?

Name: What is a peptide?
Uploaded: 2026-09-28
Duration: 1 min 10 s
Description: A peptide is a short chain of amino acids, and the order of those building blocks decides what it does.

A peptide is a short chain of amino acids, and the order of those building blocks decides what it does.

Transcript and sources

The sweetener in diet soda, a hormone that helps with childbirth, and Ozempic all have something in common.
They're all peptides: short chains of building blocks called amino acids.
Life uses twenty kinds of amino acid. String a few together, and you have a peptide. The sweetener aspartame is just two.
Order is everything. Oxytocin and vasopressin match at seven of their nine places, yet one helps with childbirth, and the other helps your body hold on to water.
In the body, many peptides are messages. One cell releases it, and it fits a receptor on another cell, like a key in a lock.
Medicines copy those messages and make them last longer, like semaglutide, built from the gut hormone GLP-1.
How short is short? U.S. drug rules draw the line at forty amino acids. Longer chains count as proteins.
One catch: calling something a peptide says what it is, not whether it works. Some are proven medicines. Others have only been tested in animals.
Build one yourself in the Peptide Lab, at peplexicon.com.

Sources