Lactobacillus rhamnosus HN001 and Reduced Anxiety

Research synthesisModerate evidenceSmall effect3 studies · 3 beneficial · 0 neutral · 0 harmful

Across 3 studies, all reported beneficial effects of Lactobacillus rhamnosus HN001 on reducing anxiety, with predominantly small effect sizes. Evidence comes primarily from a large randomized controlled trial (n=423) in pregnant and postpartum women and a systematic review of maternal populations, though one animal review also supports anxiolytic effects. The most studied population is pregnant and postpartum women, and no consistent dose range was reported across studies.

Studied populations: pregnant and postpartum women

Caveats: Only three studies available, and two of the three focus on pregnant/postpartum women — generalizability to other populations is unclear. One study is an animal review, which limits direct human applicability. Study durations were not consistently reported, making it difficult to assess time-to-effect. Doses were not extracted or consistently reported across studies.

Generated May 11, 2026

3 of 3 papersPopulation:

Effect of Lactobacillus rhamnosus HN001 in Pregnancy on Postpartum Symptoms of Depression and Anxiety: A Randomised Double-blind Placebo-controlled Trial
- 2017-10
- RCT · n = 423
- EBioMedicine 24
- - R. Slykerman
  - Fiona Hood
  - K. Wickens
  - John F. Thompson
  - C. Barthow
  - R. Murphy
  - Janice Kang
  - Judy Rowden
  - P. Stone
  - Julian Crane
  - T. Stanley
  - P. Abels
  - G. Purdie
  - Robyn M. Maude
  - E. Mitchell
- PubMed: 28943228
- DOI: 10.1016/j.ebiom.2017.09.013
6 Insights on
- Reduced Anxiety
- High evidence
- Large Human Trial
- Highly Cited
- Rigorous Journal
- Pregnant Women
Mothers in the probiotic treatment group reported significantly lower ... anxiety scores (HN001 12·0 (4·0), placebo 13·0 (4·0); effect size -1·0 (-1·9, -0·2), p=0·014)
Effect
Beneficial
Effect size
Small
Significant
Yes
Prebiotics, probiotics, and synbiotics and maternal mental health during pregnancy and postpartum period: a systematic review.
- 2026-02-17
- Systematic Review · n = 342
- Frontiers in nutrition 13
- - Sandra Martín-Peláez
  - Luis Miguel Martín-delosReyes
  - Naomi Cano-Ibáñez
- PubMed: 41783815
- DOI: 10.3389/fnut.2026.1776398
4 Insights on
- Reduced Anxiety
- High evidence
Two RCTs using Lactobacillus rhamnosus HN001, Limosilactobacillus reuteri PBS072 and Bifidobacterium breve reported small but significant reductions in depressive symptoms [Edinburgh Postnatal Depression Scale, MD = -1.2; 95% CI (-2.3, -0.1)] and anxiety symptoms [State-Trait Anxiety Inventory-6: MD = -1.0; 95% CI (-1.9, -0.2); p < 0.05)] during pregnancy.
Effect
Beneficial
Effect size
Small
Significant
Yes
The therapeutic effects of Lacticaseibacillus rhamnosus on stress-induced anxiety: a systematic review of evidence from animal studies.
- 2026-01-07
- Review · n = 8
- Gut microbiome (Cambridge, England) 6
- - Iman Imtiyaz Ahmed Juvale
  - Alina Arulsamy
- PubMed: 41497537
- DOI: 10.1017/gmb.2025.10015
6 Insights on
- Reduced Anxiety
- Low evidence
Common strains were JB-1 (n=8), HN001 (n=2), LGG (n=2), LR-32 (n=1), 4B15 (n=1), and LR3201 (n=1). Of the 15 studies, 12 reported significant anxiolytic effects
Effect
Beneficial
Effect size
Moderate
Significant
Yes

Lactobacillus rhamnosus HN001 and Reduced Anxiety

Effect of Lactobacillus rhamnosus HN001 in Pregnancy on Postpartum Symptoms of Depression and Anxiety: A Randomised Double-blind Placebo-controlled Trial

Prebiotics, probiotics, and synbiotics and maternal mental health during pregnancy and postpartum period: a systematic review.

The therapeutic effects of Lacticaseibacillus rhamnosus on stress-induced anxiety: a systematic review of evidence from animal studies.