Lost in Translation? The potential psychobiotic Lactobacillus rhamnosus (JB-1) fails to modulate stress or cognitive performance in healthy male subjects

Highlights • Lactobacillus rhamnosus (JB-1) has been shown to reduce stress-related behaviour, corticosterone release and alter central expression of GABA receptors in mice. • An 8 week, randomized, placebo-controlled, cross-over design trial was employed to assess the impact of L. rhamnosus on stress-related behaviours, physiology, inflammatory response, cognitive performance and brain activity patterns in 29 healthy male participants. • L. rhamnosus was not superior to placebo in modifying stress-related measures, HPA response, inflammation or cognitive performance. • These findings highlight the challenges associated with moving promising preclinical studies from bench to bedside.