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Gastrointestinal Health


Broad therapeutic benefits include melatonin’s role in oral care and digestive function, periodontal inflammation, post-dental surgery, and antioxidant protection against dental materials (1,2). Studies have investigated its use in Helicobacter pylori (H. pylori) infections, gastric and duodenal ulcers, gastroesophageal reflux disease (GERD), and inflammatory bowel disease (3–5). Melatonin and its precursor tryptophan have protective effects on mucosal tissue. A study in which H. pylori-infected individuals were given melatonin, placebo, or tryptophan with omeprazole is of interest. Each of the three groups had seven subjects with gastric ulcers and seven with duodenal ulcers. At the twenty-one-day mark, those treated with either tryptophan (250 mg twice daily) or melatonin (5 mg twice daily) had no ulcers, whereas the placebo group had three gastric ulcers and three duodenal ulcers. Additionally, of note is that in one study on GERD, melatonin given at 3 mg daily over eight weeks showed similar improvement in symptoms as omeprazole (5).


A study indicated that gut bacteria have a circadian clock and respond to melatonin, allowing the bacteria to synchronize with the human circadian rhythm (5). The melatonin produced in the GI tract can, in turn, assist with gut motility and mucosal integrity via its antioxidant activity and support of the microbiome. Finally, smaller-sized studies show that melatonin can improve symptoms of pain, bloating, and constipation in individuals with Irritable Bowel Syndrome-Constipation (IBS-C) and Irritable Bowel Syndrome-Diarrhea (IBS-D) presentations. Dosing melatonin at 0.3 mg daily for IBS-C and 3.0 mg for IBS-D may benefit patients with IBS (6).


Authors: Deanna Minich, Ph.D., Melanie Henning, ND, Catherine Darley, ND, Mona Fahoum, ND, Corey B. Schuler, DC, James Frame

Reviewer: Peer-review in Nutrients Journal

Last updated: September 22, 2022



1. Arushanyan EB, Karakov KG, El’bek’yan KS. Therapeutic potential of melatonin in oral cavity diseases. Vol. 75, Eksperimental’naya i Klinicheskaya Farmakologiya. 2012.

2. Cengiz MI, Cengiz S, Wang HL. Melatonin and oral cavity. International Journal of Dentistry. 2012.

3. Celinski K, Konturek PC, Konturek SJ, Slomka M, Cichoz-Lach H, Brzozowski T, et al. Effects of melatonin and tryptophan on healing of gastric and duodenal ulcers with Helicobacter pylori infection in humans. Journal of Physiology and Pharmacology. 2011;62(5).

4. Mozaffari S, Abdollahi M. Melatonin, a Promising Supplement in Inflammatory Bowel Disease: A Comprehensive Review of Evidences. Curr Pharm Des. 2012;17(38).

5. Kandil TS, Mousa AA, El-Gendy AA, Abbas AM. The potential therapeutic effect of melatonin in gastro-esophageal reflux disease. BMC Gastroenterol. 2010;10.

6. Siah KTH, Wong RKM, Ho KY. Melatonin for the treatment of irritable bowel syndrome. World J Gastroenterol. 2014;20(10).

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