Peptide

Peptides are short chains of amino acids (the “building blocks” of life) linked by covalent chemical bonds called peptide bonds.

Think of them as the smaller, nimbler siblings of proteins. While both are made of amino acids, the distinction is usually based on size: a chain of fewer than 50 amino acids is typically called a peptide, while longer chains are classified as proteins.
Three Things to Know

Biological Messengers: In your body, peptides often act as signaling molecules. For example, Insulin is a peptide hormone that tells your cells to absorb sugar, and Oxytocin (the “cuddle hormone”) is a peptide that influences social bonding.

The “Goldilocks” Size: Because they are smaller than proteins, peptides can often penetrate the skin or cell membranes more easily. This makes them highly popular in skincare (for stimulating collagen) and pharmacology (for targeted drug delivery).

Structural Variety: Even though they are short, the 20 different amino acids can be arranged in nearly infinite combinations. A sequence of just five amino acids has 3,200,000 possible variations.