Bacopa monnieri
also Bacopa · Brahmi · Water hyssop
Bacopa monnieri is an Ayurvedic herb used traditionally to support memory. Randomised trials in healthy older adults found better verbal learning and delayed recall after about 12 weeks [1][2]. A meta-analysis of nine trials found faster attention (Trail B) and choice reaction time [3]. It is slow to act and commonly causes gut side effects.
One of the few herbal nootropics with repeated positive randomised trials; expect a slow build over weeks, not an acute effect.
- meta-analysis
- RCT
- trial
- observational
- preclinical / case
- review / patent / other
- retracted
- + Repeated RCT evidence for verbal memory in older adults
- + Faster attention and reaction time in meta-analysis
- + Possible reductions in anxiety alongside
- − Takes around 12 weeks to show effects in trials
- − Stomach upset, cramps and more frequent stools
- − Extracts vary between products
Overview
Bacopa is a creeping wetland herb with a long history in Ayurvedic medicine as a memory tonic. Modern products are usually extracts standardised to their bacoside content.
Most of the clinical evidence comes from healthy or older adults. In a trial of 98 healthy older Australians, 12 weeks of bacopa significantly improved verbal learning, memory acquisition and delayed recall compared with placebo [1]. A separate 12-week trial in elderly adults found improved delayed word recall and Stroop performance, along with reduced depression and anxiety scores [2]. A meta-analysis of nine trials (518 participants) found faster Trail B performance and quicker choice reaction times [3].
Mechanism
The human mechanism is not established. Research attention has focused on the bacosides, the saponins that extracts are standardised to. A 2021 analysis of the clinical data found modest improvements in people with memory loss, but inconsistent results in healthy people, where no two studies found significant changes on the same two tests [4].
- Bacosides (active saponins)modulatesthe constituents usually standardised for; their human mechanism is not establishedunclear
Safety
risks and cautions, not medical adviceBacopa's side effects are mainly gastrointestinal. In one trial it caused more frequent stools, abdominal cramps and nausea compared with placebo [1]. In another, adverse events were few and mostly stomach upset, at rates similar to placebo [2].
- Extracts are not interchangeable; results come from specific standardised preparations
Interactions
documented pairs only, not exhaustive- Rhodiola roseacompatibleNo interaction documented; commonly combined in adaptogen blends
FAQ
- How long does bacopa take to work?
- The positive trials measured effects after about 12 weeks of daily use [1][2].
- Why does bacopa upset my stomach?
- Gastrointestinal effects are its most consistent side effect in trials [1]. Taking it with food is common practice, though not a trial finding.
References
entry last reviewed 2026-09-18- [1]Does Bacopa monnieri improve memory performance in older persons? Results of a randomized, placebo-controlled, double-blind trial.Morgan A, Stevens JJ Altern Complement Med 2010RCT · humanPMID 20590480◌ unreviewed
- [2]Effects of a standardized Bacopa monnieri extract on cognitive performance, anxiety, and depression in the elderly: a randomized, double-blind, placebo-controlled trial.Calabrese C, Gregory WL, Leo M et al.J Altern Complement Med 2008RCT · humanPMID 18611150◌ unreviewed
- [3]Meta-analysis of randomized controlled trials on cognitive effects of Bacopa monnieri extract.Kongkeaw C, Dilokthornsakul P, Thanarangsarit P et al.J Ethnopharmacol 2014meta-analysis · humanPMID 24252493◌ unreviewed
- [4]The effectiveness of Bacopa monnieri (Linn.) Wettst. as a nootropic, neuroprotective, or antidepressant supplement: analysis of the available clinical data.Brimson JM, Brimson S, Prasanth MI et al.Sci Rep 2021meta-analysis · humanPMID 33436817◌ unreviewed