Gastric hydrochloric acid (HCl) (HCl)

Gastric hydrochloric acid is a key component of gastric juice, secreted by the parietal cells of the stomach (Britannica, 2023). It plays a vital role in digestion by denaturing dietary proteins and providing the highly acidic environment necessary for the conversion of the zymogen pepsinogen into the active protease pepsin (NIH, 2024). Additionally, its low pH serves as a critical protective barrier against ingested microorganisms, acting as a first-line antimicrobial defense. However, when the balance between acid secretion and mucosal protection is disrupted, it contributes to the pathogenesis of gastroesophageal reflux disease (GERD), gastritis, and peptic ulcers (StatPearls, 2023). While many pharmacological agents like proton pump inhibitors target the enzymes responsible for acid production, antacids directly target the hydrochloric acid already present in the gastric lumen. These agents work through a simple chemical neutralization reaction, rapidly increasing the pH of the stomach contents to provide symptomatic relief from dyspepsia and protect the esophageal and gastric mucosa from acid-mediated damage (PubChem, 2024).

Other names

Stomach acidGastric acidHydrogen chlorideMuriatic acid

Direct chemical neutralization of hydrochloric acid in the gastric lumen to form water and neutral salts, thereby increasing gastric pH (StatPearls, 2023).