Amino acids are organic compounds composed of nitrogen, carbon, hydrogen and oxygen, along with a variable side chain group – and they are the starting point for peptide synthesis.
A peptide is a polymer of amino acids connected by covalent amide bonds formed by the nucleophilic addition-elimination reaction between the carboxylic group of one amino acid and the amino group of another amino acid, with the elimination of a molecule of water.
The biochemical activity of peptides is characterised by their individual structure, size and shape, and these factors are determined by the sequence and characteristics of the constituent amino acids.
While amino acids and hydrolysed proteins have been commonly available for cosmetic products for decades the use of targeted peptides is more recent. This is largely due to a better understanding of the human genome and how peptides are used by the body for vital processes like the building of proteins and the synthesis of hormones and neurotransmitters.