Supports Nighttime Gastric Health and Comfort Use with GI Guard AM A Dietary Supplement Vegetarian/Vegan How It Works: GI Guard PM is a nutritional formula with PepZin GI, Melatonin, Amino Acids, and B Vitamins designed to help maintain the strength and integrity of the gastrointestinal mucosal barrier. GI Guard PM features PepZin GI, which has been shown in clinical studies to promote a healthy stomach lining and to support proper gut repair processes. Melatonin, a potent free radical scavenger, is known to exist at high levels in the gut, where it exerts its protective effects against oxidative stress throughout the gastrointestinal tract. Melatonin also helps support healthy gastric pH levels, normal pepsin production in the stomach, and helps to regulate proper intestinal motility. B Vitamin and Amino Acids, such as Tryptophan are necessary for Melatonin synthesis.