Could a gut microbiome transplant help patients sleep?

Clinical takeaway: In a randomized, double-blind, placebo-controlled trial, fecal microbiota transplantation (FMT) delivered via oral capsules improved both objective sleep measures and patient-reported sleep quality in adults with chronic insomnia, supporting the gut microbiome as a potential therapeutic target.

Current insomnia treatments can be limited by tolerability, accessibility, adherence, and durability of benefit. These findings suggest that targeting the gut-brain axis may offer a novel therapeutic approach for chronic insomnia.

In this randomized, double-blind, placebo-controlled trial, 80 adults with chronic insomnia disorder were assigned to receive oral capsules containing fecal microbiota from healthy donors (n=40) or placebo (n=40). The study's primary endpoint was polysomnography-measured sleep efficiency at 1 month.

At 1 month, participants receiving donor microbiota demonstrated higher sleep efficiency and less wakefulness after sleep onset on overnight polysomnography, indicating more consolidated sleep. Improvements were also reflected in patient-reported outcomes, with sleep-quality scores continuing to improve from 2 to 6 months after treatment compared with placebo.

The findings add clinical support to growing evidence that the gut microbiome influences sleep regulation through the gut-brain axis. Exploratory analyses suggested that FMT was associated with favorable changes in autonomic nervous system activity and remodeling of gut microbial composition, providing potential mechanistic insight into the observed sleep benefits.

“Our findings provide clinical evidence that targeting the gut microbiota may offer a promising new therapeutic strategy for chronic insomnia disorder,” said co-corresponding author Yanping Bao, PhD, of Peking University. “This work also strengthens our understanding of the gut-brain axis as an important regulator of human sleep.”

Source: Gao T, et al. (2026 July 20) J Intern Med. Fecal microbiota transplantation-based treatment protocol for chronic insomnia disorder: A randomized, double-blind, placebo-controlled trial