Thank you for providing detailed information on PPIs and their alternatives. Although, melatonin is mainly used to treat sleep disorders, it was found that low levels of this hormone produced in the body by the pineal gland can lead to gastroesophageal reflux disease (GERD). Studies also determined that melatonin has an inhibitory effect on the secretion of gastric acid, and participates in the controlling of the lower esophageal sphincter. Today, PPIs are the main medication used to reduce stomach acid and relieve GERD symptoms. Due to numerous side effects of PPIs drugs, especially when used long-term, health care provides recommend other alternatives, and melatonin is one of them. The first mechanism of melatonin’s action is the strengthening of the lower esophageal sphincter. Since relaxation of this sphincter is the main cause of acid reflux, its strengthening helps to prevent stomach contents from coming back up into the esophagus. Besides that, melatonin inhibits the production of nitric oxide – a chemical compound that relaxes the lower esophageal sphincter and allows for acidic contents to enter the esophagus and cause heartburn.