What are peptides?
The short version: peptides are small chains of amino acids your body already uses as messengers.
Building blocks
Amino acids are the building blocks of protein. Link a few of them together and you have a peptide. Link many together and you have a protein. The line between the two is fuzzy, but peptides are generally under about 50 amino acids.
Messengers, not fuel
Many peptides work as signals. They fit into specific receptors on cells, like a key in a lock, and tell those cells to do something: release a hormone, change appetite, start a repair process. Insulin is a peptide hormone. So is the GLP-1 hormone your gut releases after a meal.
Natural, modified, and synthetic
Some peptides discussed today are copies of ones the body makes. Others are modified to last longer or bind more strongly. Semaglutide, for example, is a modified version of GLP-1 that lasts about a week instead of minutes.
Why evidence matters so much
The peptide world ranges from FDA-approved medicines tested in tens of thousands of people to compounds studied only in rats. Online, they're often talked about the same way. That's why every page in our library shows itsevidence level.
Common questions
What is a peptide?
A peptide is a short chain of amino acids, the same building blocks that make up proteins. Peptides are generally under about 50 amino acids long; longer chains are usually called proteins.
Are peptides the same as steroids?
No. Steroids are built on a ring-shaped lipid structure. Peptides are chains of amino acids and act mostly by binding to specific receptors on cells.
Are peptides FDA-approved?
Some are. Insulin, semaglutide, and tirzepatide are FDA-approved peptide medicines. Many peptides discussed online are not approved, and their safety and effectiveness in people have not been established.
Is collagen a peptide?
Collagen is a large protein. Collagen supplements are often "hydrolyzed" into smaller collagen peptides so they are easier to digest. These are food products, not the same as therapeutic peptides.