Types of peptides

Peptides, Peptides, Active Peptides, and Peptides 

Peptides with a molecular weight range between 50 and 5000 are called peptides. Peptides with molecular weights ranging from 5000 to 10000 are called large peptides. Peptides with molecular weights ranging from 50 to 2000 are called small peptides, oligopeptides, or low molecular weight peptides, also known as small molecule active peptides. 

Biologists refer to peptides as "amino acid chains" and small molecule active peptides collectively as "biologically active peptides". Common types include dipeptides, tripeptides, and even polypeptides, with 2-10 peptides belonging to oligopeptides and 10-50 peptides belonging to peptides. Typically, peptides with less than ten peptides are more practical for medicine and commerce.