Probiotic strain identified by Cryan and Dinan (APC Microbiome Ireland) as a potential 'psychobiotic'. In animals it reduces anxious behavior and cortisol via the vagus nerve, but in humans the trials have been disappointing.
1–10 billion CFU/day. Published human studies used 1×10^9 CFU for 4–8 weeks. Currently no clearly standardized commercial product.
How to take it
1–10 billion CFU/day. Published human studies used 1×10^9 CFU for 4–8 weeks. Currently no clearly standardized commercial product.
Safety
Very safe in usual probiotic practice. Caution in severe immunosuppression and with a central venous line. Well tolerated.
Effect by goal · level of evidence
Anxiety and stress (animal)
improvesModeraterobust preclinical (A)
Clear vagal effect
In mice/rats it reduces anxious behavior, attenuates reactive cortisol, and modifies GABA receptors in the amygdala and hippocampus. Effect abolished by vagotomy (vagus nerve-dependent).
Crossover trial in 29 healthy men over 8 weeks: NO changes in reactive cortisol, self-reported anxiety, or cognition. Failure of translation from the animal model.
Canonical example of a vagus-dependent strain: the mechanistic basis of the term 'psychobiotic'. Clinical usefulness in humans awaits new RCTs with different doses and matrices.
Information, not medical advice. Scientific evidence reflects the quality of the studies.