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Bl73.0
B. longum 1714 Research
Mostly mechanism / observational
9 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most B. longum 1714 studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from medium-quality randomised trials published 2015–2026 with a typical study size of 72 participants.
Based on 9 studies · 5 RCTs · 411 total participants
Confidence
Moderate confidence
By outcome
Stress & cortisolPossible reduction in self-reported stress, but the effect rests on a non-randomised 22-person study and was absent in a 20-student exam-stress trial · 4 weeks
Mostly mechanism / observational4 studies
Sleep & well-beingSubjective sleep-quality components improved at 4 weeks in two trials, but the primary sleep endpoint was missed and objective actigraphy was unchanged · 4 weeks
Mostly mechanism / observational4 studies
Mood & depressive symptomsNo established benefit — the dedicated 168-person depression trial missed its primary endpoint at both timepoints · 8 weeks
Mostly mechanism / observational3 studies
Cognition & neurocognition
Mostly mechanism / observational3 studies
EEG & brain-activity biomarkers
Mostly mechanism / observational3 studies
Immune & tryptophan metabolism
Too few graded studies2 studies
Active research area
5 studies in the last 5 years
201520202026
1RCTn=89 · small study2024
In plain English: The dedicated sleep trial missed its primary endpoint, and objective actigraphy found no effect on sleep at all.
Patterson E et al. · Sci Rep (2024)
PRIMARY ENDPOINT MISSED: PSQI global score improved in both groups, with no significant advantage for the strain
Secondary subjective outcomes were significant: PSQI sleep-quality component and daytime dysfunction at 4 weeks, social functioning and energy/vitality at 8 weeks (all p<0.05)
OBJECTIVE MEASURE NULL: no significant effect on any actigraphy measure
In plain English: The largest trial of this strain, in 168 adults with mild-to-moderate depression, missed its primary endpoint at both week 4 and week 8.
Seamans KM et al. · Exp Clin Psychopharmacol (2026)
PRIMARY ENDPOINT MISSED: BDI-II change vs placebo was -0.303 (95% CI -1.957 to 1.35, p=.718) at week 4 and -1.432 (95% CI -3.30 to 0.44, p=.132) at week 8
Week-4 secondary outcomes PSQI total (-0.923, 95% CI -1.62 to -0.23, p=.009) and PHQ-9 (-1.013, 95% CI -2.00 to -0.02, p=.045) did NOT hold at week 8
SF-36 subscores improved at week 4 (vitality p=.038, mental health p=.032, social role functioning p=.033); only vitality remained significant at week 8 (p=.042)
In plain English: In pregnancy, supplementation from mid-gestation to delivery had no effect on the maternal immune response it was designed to change.
Killeen SL et al. · Cytokine (2024)
PRIMARY ENDPOINT NULL: LPS-stimulated IL-10 fold change was 88.45 in the intervention group vs 24.18 in control, p=0.183
Anti-CD3/28/2-stimulated IL-10 also null (189.69 vs 148.74, p=0.506)
The trial was powered for 68 subjects at 80% power, so it was adequately sized for its endpoint
In plain English: Brain oscillations changed on magnetoencephalography, but the trial states plainly that there was no effect at the behavioural level.
Wang H et al. · Am J Gastroenterol (2019)
Increased theta band power in frontal and cingulate cortex and decreased beta-3 band power in hippocampus, fusiform and temporal cortex (both P<0.05), correlating with subjective vitality
EXPLICIT BEHAVIOURAL NULL: all groups showed increased social stress after 4 weeks 'without an effect at behavioral level due to small sample numbers'
After the Cyberball social-stress paradigm, only the probiotic group showed altered neural oscillation (increased frontal/cingulate theta and alpha, and supramarginal gyrus, P<0.05)
In plain English: The mechanistic case: a strain-specific exopolysaccharide that induces IL-10, plus tryptophan and indole lactic acid that damp down TLR signalling.
Groeger D et al. · Curr Res Microb Sci (2025)
The strain produces a branched hexasaccharide repeating-unit exopolysaccharide that selectively induces IL-10 secretion from human PBMCs
It also produces tryptophan and indole lactic acid in vitro; indole lactic acid directly reduced TLR-induced pro-inflammatory cytokine secretion and NF-kB activation
Consumption reduced excessive cytokine responses in LPS-induced, stress-induced and obesity-induced inflammation in MOUSE models
In plain English: The paper that made this strain famous is not a randomised controlled trial — placebo always came first, so its findings cannot be separated from order effects.
Allen AP et al. · Transl Psychiatry (2016)
PubMed classifies this as a Controlled Clinical Trial, NOT a Randomized Controlled Trial
Within-participants design in 22 healthy volunteers: assessments at baseline, then post-placebo, then post-psychobiotic — placebo ALWAYS preceded the probiotic
No randomisation of order and no parallel placebo arm, so improvements are confounded with repeated testing and expectancy