Microbes From Healthy Donor Stool May Help Treat Chronic Insomnia

At 3 a.m., when sleep has slipped away again, the last place a person might look for help is inside someone else’s gut.

That is exactly where a new clinical trial looked. Adults with chronic insomnia who received capsules containing fecal microbes from healthy donors slept more efficiently and spent less time awake after initially falling asleep than those given a placebo.

Published in the Journal of Internal Medicine, the findings provide early evidence that changing the gut microbiome may influence how well people sleep.

“Targeting the gut microbiota may offer a promising new therapeutic strategy for chronic insomnia disorder,” said co–corresponding author Yanping Bao in a press release. “This work also strengthens our understanding of the gut–brain axis as an important regulator of human sleep.”

Fecal Microbiota Transplantation Trial Tests a New Approach to Chronic Insomnia

The trial followed 80 adults with chronic insomnia across seven hospitals in China. Half received capsules made with microbes collected from screened donor stool, a treatment called fecal microbiota transplantation. The other half received placebo capsules.

Before taking the capsules, the treatment group spent two days on antibiotics to reduce the bacteria already living in their guts. Researchers hoped this would give the donor microbes a better chance to settle in. Following a two-day break, participants swallowed 60 capsules and received another 20 two weeks later.

One course contained approximately 200 billion living microbes. Because the study focused on sleep, donors underwent screening for sleep disorders and serious psychiatric symptoms, as well as infections and other health concerns.

Neither participants nor the researchers measuring their sleep knew who had received the treatment. One month later, an overnight test recorded how long participants slept and how often they woke. Researchers focused on sleep efficiency, the percentage of time in bed spent asleep.

Sleep Became Less Interrupted Before Participants Felt the Difference

Median sleep efficiency in the treatment group climbed from 79.3 percent before treatment to 93.2 percent one month later. The placebo group barely changed, moving from 84.6 percent to 86.7 percent.

After researchers accounted for differences between the groups before treatment and across the seven hospitals, the improvement in sleep efficiency was 13.9 percentage points greater with the full treatment. Participants receiving the treatment also spent 41.5 fewer minutes awake after initially falling asleep.

The treatment group recorded 48.6 more minutes of total sleep, but that result was no longer statistically significant after researchers considered all the sleep measurements they had tested. The study therefore provides stronger evidence that the treatment reduced sleep interruptions and increased the total amount of sleep during the night.

Both groups felt better after the first month, even though the overnight recordings favored the treatment group. By months two and three, those receiving the treatment reported better sleep than the placebo group. That advantage remained six months later, although it had weakened.

The gut samples told a less straightforward story. Antibiotics initially reduced the variety of microbes, but that diversity recovered after participants took the donor capsules. Even so, a bigger change in the gut did not necessarily mean better sleep.

The Antibiotics Make the Results Harder to Untangle

Because only the treatment group received antibiotics, researchers cannot know whether the improvement came from the capsules, the antibiotics, or both. Routine use would also expose people to antibiotics for a condition unrelated to infection, possibly contributing to drug resistance.

Three participants experienced nausea, vomiting, or fever, and one withdrew, but the trial found no serious safety problems.

Fecal microbe capsules are not ready for the bedside table. Still, the findings give researchers another reason to look beyond the brain when sleep keeps breaking apart.

This article is not offering medical advice and should be used for informational purposes only.

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