Melatonin plays a role in suppressing inflammation, scavenging free radicals, and increasing endorphins to decrease pain:

Bert Folsom | Dreamstime

People with irritable bowel syndrome can suffer for years without finding a way to relieve their symptoms, but a new review article reveals a promising treatment option: melatonin benefits for IBS. Produced by the pineal gland in the brain and by cells in the mucous lining of the digestive tract, this hormone is mostly known for its role as a chemical signal that regulates the sleep-wake cycle by causing drowsiness and lowering body temperature. But that’s not all it does.

Research Suggests That Natural Remedies for IBS Should Include Melatonin

Researchers at the National University of Singapore’s School of Medicine recently published a review article, “Melatonin for the treatment of irritable bowel syndrome,”  in the World Journal of Gastroenterology that looked at how melatonin benefits IBS._[1] They summarized the available evidence from at least four randomized, double-blind, placebo-controlled studies, all showing that melatonin decreases abdominal pain. Most of the studies used 3 mg of melatonin at bedtime, although one study in postmenopausal women used 3 mg in the morning plus 5 mg at bedtime. The evidence was not as clear as to whether melatonin reduces other symptoms of IBS, such as abdominal distention/bloating, abnormal sensation of defecation, diarrhea, or constipation.

• In one of the studies, 3 mg of melatonin for 8 weeks significantly improved patients’ overall IBS scores compared with placebo._[2] Those taking melatonin had a 45% improvement on their IBS symptom score versus a 16% improvement for patients taking placebo. They also had significant improvements in symptoms not related to gut function and in overall quality of life.
• In a second study, 3 mg of melatonin at bedtime for only two weeks significantly improved abdominal pain and reduced sensitivity to pain in the rectal area._[3] There was also a tendency towards a greater reduction in abdominal distension, stool frequency, and total bowel symptoms following treatment with melatonin than with placebo.
• A third study found that six months of melatonin (3 mg in the morning and 5 mg in the evening) significantly reduced abdominal pain, bloating, and constipation in postmenopausal women with constipation-predominant IBS._[4] Women with diarrhea-predominant IBS also noted beneficial changes, but the effects were not statistically different from those in the placebo group.
• A fourth study found that 3 mg of melatonin at bedtime for eight weeks resulted in significant improvements in abdominal distension, abdominal pain (pain intensity and frequency), and abnormal sensation of defecation._[5] Melatonin did not affect stool consistency or frequency.

Additional Melatonin Benefits

Melatonin plays a role in suppressing inflammation, scavenging free radicals, and increasing endorphins to decrease pain. Within the gastrointestinal system, melatonin regulates the movement of food, controls inflammation, and modulates sensation. Safe, inexpensive, and widely available as a supplement, it improves insomnia and circadian rhythm sleep disorders, cancer, immune disorders, and migraines.

To try melatonin for IBS, start with 3 mg at bedtime. If you notice that you are tired or groggy the next day, reduce the dose to 1 or 2 mg. Stick with the treatment for at least one or two months to obtain optimal benefits. Other natural IBS treatments include enteric-coated peppermint oil, the FODMAPs diet, and eliminating foods to which you’re allergic or sensitive. The following articles provide information on these additional IBS therapies:

• Peppermint Benefits — Relief for IBS, Tension Headaches & More
• IBS Trigger Foods: FODMAPs Diet Identified as the Primary Culprit
• Natural Treatment for Migraines and IBS: Start with a Blood Test for Food Allergies

Share Your Experience with Melatonin for IBS

What treatments have you tried for IBS? What has been successful? Please share your experiences in the comments section below.

[1] World J Gastroenterol. 2014 Mar 14;20(10):2492-2498.

[2] J Clin Gastroenterol. 2007 Jan;41(1):29-32.

[3] Gut. 2005 Oct;54(10):1402–1407.

[4] Endokrynol Pol. 2013;64(2):114-20.

[5] Aliment Pharmacol Ther. 2005 Nov 15;22(10):927-34.

Originally published in 2014 and is regularly updated.