A Gut Probiotic Showed Real Promise for Insomnia—Here's What the Science Found

A specific probiotic strain called Lactiplantibacillus plantarum Lp815 significantly improved sleep quality and reduced insomnia symptoms in adults with sleep disturbance, according to a new randomized controlled trial. The study found that 77.3% of participants taking the probiotic showed meaningful improvement in their insomnia severity scores after six weeks, compared to 57.8% in the placebo group.

How Does This Probiotic Actually Work for Sleep?

The key lies in a brain chemical called gamma-aminobutyric acid (GABA), which acts as the body's main "brake pedal" for the nervous system. When GABA levels are adequate, it helps calm brain activity and promote restful sleep. The Lp815 strain produces significant amounts of GABA in the gut, even in the less acidic environment of the large intestine where many other probiotic strains struggle to function effectively.

In the study, researchers tracked urinary GABA levels in a subset of 17 participants and found that those taking the probiotic showed increased GABA levels during the first week of use. Importantly, higher GABA levels were linked to lower insomnia and anxiety scores throughout the study period.

What Were the Specific Results?

The six-week study involved 139 adults with moderate insomnia symptoms, aged 44 years on average, with 51.1% being female. Participants received either 5 billion colony-forming units (CFU) of Lp815 daily or a placebo capsule. The results showed multiple sleep and mood benefits:

• Insomnia Improvement: Participants taking Lp815 had significantly lower insomnia severity scores compared to placebo, with the improvement being clinically meaningful
• Anxiety Reduction: Anxiety scores decreased significantly, with women showing particularly pronounced benefits
• Sleep Duration: Objective sleep tracking showed increased sleep duration in the probiotic group
• Night Sweats: Subjective reports of night sweat severity decreased among those taking the probiotic

All adverse events related to the probiotic were mild, suggesting it's well-tolerated for most people. The study was conducted as a decentralized, double-blind trial, meaning neither participants nor researchers knew who was receiving the active treatment until the end.

Why This Matters for Sleep Health?

Sleep problems have reached crisis levels in the United States, with 20% of adults sleeping five hours or less per night and only 26% getting the recommended eight or more hours. Sleep deficits contribute to cognitive decline, mood disorders, metabolic illness, and other serious health conditions.

Current treatments often come with significant drawbacks. Prescription sleep medications like Ambien carry warnings about side effects and are associated with earlier cognitive decline when used chronically. Even over-the-counter options like melatonin can disrupt circadian rhythms and cause morning grogginess with long-term use.

This probiotic approach offers a potentially safer alternative by working with the body's natural gut-brain connection. The sustained GABA production from the probiotic may provide more stable benefits compared to medications that have short-lived effects and require frequent dosing.

The research builds on previous findings that the same Lp815 strain significantly improved anxiety symptoms in adults, suggesting this particular probiotic may address the interconnected nature of sleep and mood disorders that affect over 70% of people with anxiety.