Pepsin

Also known as pepsine.

Last reviewed October 9, 2026 · Jump to references

What is Pepsin?

In plain words

Pepsin is an enzyme, a protein that helps break food proteins into smaller pieces in the stomach. The stomach makes an inactive form that stomach acid switches on. Researchers study its role in digestion and in tissue irritation when stomach contents flow back into the throat. Its normal role in digestion is well established, but that does not mean pepsin supplements benefit everyone.

Technical definition

Pepsin is a gastric aspartic protease formed by acid-dependent activation of pepsinogen, an inactive precursor secreted by stomach chief cells. Rather than acting on a receptor, it catalyzes the hydrolysis of internal peptide bonds in dietary proteins, particularly near hydrophobic amino acid residues, producing smaller peptides in the acidic stomach environment. Commercial pepsin is commonly derived from porcine gastric tissue, and regulatory classification depends on the product and jurisdiction.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.