Melatonin in IBS: less pain did not mean different stools

The study and its comparison

Forty adults with irritable bowel syndrome and sleep disturbance were randomized to melatonin or placebo for two weeks. Investigators collected bowel and sleep questionnaires, rectal sensitivity measurements and overnight sleep recordings. [1]

Melatonin reduced reported abdominal pain and increased the rectal pain threshold. Bloating, stool type, stool frequency and psychological scores did not significantly differ. Objective and questionnaire sleep measures also did not improve. [1]

What the finding establishes

This short trial does not show that melatonin treats constipation or every form of IBS. It illustrates that pain sensitivity, bowel habits and sleep can respond differently. Funding and conflicts were not established from the abstract. A research regimen is not an individual treatment recommendation. [1]

A hypothetical distinction

Imagine abdominal pain improves while stool frequency stays unchanged. Calling that a laxative effect would misstate the result.

Interpretation checklist — Melatonin in IBS
Detail	Interpretation
Measured outcome	Keep the endpoint specific
Study preparation	Not every retail product
Remaining uncertainty	Not resolved by a mechanism

Melatonin in IBS: less pain did not mean different stools — original article outline diagram — Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

Sources for this article

Melatonin improves abdominal pain in irritable bowel syndrome patients who have sleep disturbances: a randomised, double blind, placebo controlled study.
Source consulted: 2026-09-19. This is a reference resource, not a claim that we conducted the studies or tested a product.