Peptide

Definition

A peptide is a molecule composed of two or more amino acids joined by peptide bonds. Peptides are smaller than proteins (typically under 50 amino acids) and act as hormones, signaling molecules, and enzyme regulators. Therapeutic peptides exploit this signaling role to produce clinical effects — for example, insulin (51 AAs) and semaglutide (31 AAs).

Related terms

• Amino AcidThe building block of peptides and proteins — 20 standard amino acids occur in human biology.
• ProteinA polypeptide folded into a three-dimensional structure with biological function.
• PolypeptideA longer chain of amino acids, typically 50+ residues — the category between peptides and proteins.

Compounds that reference Peptide

• BPC-157A gastric pentadecapeptide studied extensively in animal models for tissue healing, gut protection, and cytoprotective properties. Despite over 100 preclinical studies, human clinical data remains extremely limited.
• TB-500A naturally occurring peptide central to cell migration and tissue repair. Phase 2 human wound healing trials showed accelerated healing; also studied for cardiac and corneal repair.
• GHK-CuA naturally occurring copper-binding tripeptide with research supporting skin remodeling, wound healing, and anti-aging properties.
• EpithalonA tetrapeptide studied for its potential to activate telomerase and extend cellular lifespan, primarily in Russian research.
• SelankA synthetic peptide analog of tuftsin, approved in Russia for anxiety and studied for nootropic and immunomodulatory properties.
• SemaxA synthetic peptide analog of ACTH(4-10) approved in Russia as a nootropic, studied for cognitive enhancement and neuroprotection.