What are peptides?
Written and maintained by the AVERON Research Desk · Last reviewed September 2026
A peptide is a short chain of amino acids, the same building blocks that make up proteins. Where a protein may contain hundreds or thousands of amino acids folded into a complex shape, a peptide is usually somewhere between two and about fifty. That small size is what makes peptides chemically and biologically distinctive.
Amino acids and peptide bonds
The body uses twenty standard amino acids. Each has the same basic backbone and a different side chain, which gives it its particular chemical character. When two amino acids join, they form a chemical link called a peptide bond. Join a few more and you have a peptide. The exact order of amino acids, known as the sequence, determines what the peptide is and what it does.
Two peptides made of the same amino acids in a different order are different molecules with different properties. That is why a single substitution in a sequence can turn one compound into another.
What peptides do in the body
Many of the body's own signalling molecules are peptides. Hormones such as GLP-1, which is released from the gut after eating, and oxytocin are peptides. So are many growth factors and neurotransmitters. They work mostly by binding to specific receptors on the surface of cells, which then trigger a response inside the cell.
Because they bind to their receptors very specifically, peptides tend to act on a narrow set of targets. This is one reason they attract so much research interest: in principle, a peptide can switch on or off one pathway without disturbing many others.
Peptides as medicines
Peptides are not new to medicine. Insulin, a peptide hormone of 51 amino acids, has been used to treat diabetes for a century. More than eighty peptide medicines are now approved around the world, including the GLP-1 class of drugs used for type 2 diabetes and weight management.
Their main limitation has always been delivery. Most peptides are broken down by digestive enzymes, so they usually cannot be taken as tablets. Many also break down quickly in the blood. Much of modern peptide drug development is about making molecules that last longer or survive in the body better.
How research peptides are made
Most research peptides are produced by chemical synthesis rather than extracted from living tissue. The dominant method, solid-phase peptide synthesis, builds a peptide one amino acid at a time on a solid support. It was developed by Robert Bruce Merrifield, who received the Nobel Prize in Chemistry for it in 1984.
After synthesis, the peptide is purified, usually by chromatography, and freeze-dried into a stable powder. That powder is what arrives in a vial. We explain it in what is lyophilized peptide powder.
What "research peptide" means
A research peptide is a peptide supplied for laboratory research rather than as a medicine. Some research peptides are the same molecules as approved medicines. Many are compounds that have only been studied in animals. The distinction matters, and every compound page on this site states which is which.