The IBS in Women Study

A double-blind, randomized, placebo-controlled study assessing the impact of probiotic supplementation on the symptoms of irritable bowel syndrome in females


Lab4 probiotics demonstrated a significant reduction in the severity scores of IBS-symptoms among women aged 18 to 40, alongside improvements in bowel habits.

Notably, 63% of women receiving Lab4 probiotics experienced clinically meaningful reductions in symptom severity (≥50 points), in contrast to the minimal improvements seen in the placebo group (4%).

Additionally, significant reductions in anxiety, depression, and IBS-related control and avoidance behaviour were also observed.


The aim of this randomised, double-blind, placebo-controlled study was to confirm the beneficial effect of Lab4 probiotics on IBS symptoms in women aged 18 to 40 years.



IBS symptoms

  • A significant reduction in Total IBS symptom scores in women supplemented with Lab4 probiotics (Group 2) compared to Group 1 was observed during the 8-week study (**P=0.0018, ****P<0.0001).
  • Reductions of ≥50 points are considered clinically meaningful. By the end of this study, 63% of women in Group 2 achieved such a reduction in severity, compared to only 4% for Group 1.
  • In Group 2, the reduction in the IBS-symptom severity score was associated with fewer days with abdominal pain, reduced pain and bloating severity, and improvements in bowel habit satisfaction and overall well-being.

Bowel habits

  • The proportion of women with normal stool consistency in Group 2 was significantly higher than in Group 1 (P=0.0106).
  • In Group 2, there were fewer defecation with loose stools (P=0.0311).

Anxiety, Depression, and IBS-related behaviour

  • Significant reductions in both anxiety and depression scores were observed in Group 2 compared to Group 1 at the end of the study (***P=0.0002 and ****P<0.0001, respectively).
  • Lab4 supplementation (Group 2) significantly reduced IBS-related avoidance and control behaviour (such as food anxieties or the avoidance of social situations; ***P=0.0002).


This is a second study demonstrating the benefits of Lab4 probiotic supplementation in the management of IBS.  

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