What is the primary location of protein digestion in the human body?

Protein digestion predominantly occurs in the stomach, which is supported by the action of gastric juices that contain hydrochloric acid and the enzyme pepsin. These components work together to denature protein structures, making them more accessible for enzymatic breakdown. Pepsin specifically cleaves the peptide bonds in proteins, initiating the digestion process.

While the small intestines play a significant role in further digestion and absorption of proteins—where enzymes from the pancreas continue the breakdown of polypeptides into amino acids and small peptides—most of the initial breakdown stages happen in the stomach. Therefore, the stomach is considered the primary site for protein digestion. The mouth has limited digestive activity primarily for carbohydrates and fats, whereas the rectum is involved in waste elimination rather than digestion.