The difference between peptides and peptide solutions lies in their different definitions. 1. Peptide is a compound in which two or more amino acids are connected by peptide bonds. It is an intermediate substance between amino acids and proteins. 2. Peptide liquid generally refers to peptides, which are small protein molecules composed of amino acid molecules and can be digested and absorbed by the human body. The molecular weight of peptide liquid is between 180 and 5000 Daltons. Among them, those with molecular weights between 1000 and 5000 Daltons are called large peptides, and those between 180 and 1000 Daltons are called small peptides, oligopeptides, Oligopeptides are also called small molecule active peptides.