Benefits
Memory consolidation and recall of new information
In placebo-controlled trials lasting about 12 weeks, standardized bacopa extracts improved retention of newly learned word lists and delayed recall in healthy adults, including people over 55 and over 65. A systematic review of six such trials found improvement on 9 of 17 memory free-recall tests, with little evidence for other cognitive areas. Benefits were measured after about 12 weeks of daily use.
Faster information processing and attention speed
A meta-analysis of nine placebo-controlled trials lasting at least 12 weeks found shorter Trail Making B times and faster choice reaction time with bacopa, pointing to quicker attention. One trial also found faster visual information processing and a better learning rate, and another found better spatial working memory accuracy. A third trial found learning rate unchanged, so results vary by test.
Lower anxiety scores in healthy adults
In a 12-week trial in healthy adults, bacopa lowered state anxiety compared with placebo. In adults aged 65 and over, combined state and trait anxiety scores fell with bacopa while rising with placebo. A third 12-week trial in adults aged 40 to 65 found no change in anxiety. All three trials were small.
Memory support in healthy older adults
Two 12-week placebo-controlled trials in healthy people over 55 and over 65 found better verbal learning and delayed word recall with 300 mg a day of standardized extract. Lab and animal studies suggest antioxidant and cholinergic actions, but these 12-week trials did not test long-term effects on brain aging.
Attention and behavior in children and teens
A systematic review of five studies in children and adolescents reported improvements in language, several memory measures, and attention and hyperactivity ratings, with small to medium effect sizes (average d of 0.42). About 2 percent of participants reported mild side effects. The authors call for replicated trials, and any use in a child should be discussed with a pediatrician.
Digestive side effects to expect
In a 12-week trial in adults over 55, bacopa caused more digestive side effects than placebo: more frequent stools, abdominal cramps and nausea. In a trial in adults over 65, adverse events were few and similar in number to placebo (9 versus 10), mostly stomach upset. The trials did not test whether taking bacopa with food reduces these effects.
Trials used standardized extracts
The positive trials used standardized bacopa extracts such as KeenMind and BacoMind at 300 mg a day, and a systematic review noted three different extracts tested at 300 to 450 mg a day. Results from these extracts may not apply to unstandardized whole-herb powders, which these trials did not test.
Mechanism of action
Cholinergic activity
In lab and animal studies, bacopa compounds inhibited acetylcholinesterase, the enzyme that breaks down the memory-related messenger acetylcholine, and may activate choline acetyltransferase, the enzyme that makes it. These effects have not been measured directly in people.
Blood flow and neurotransmitter effects
A review of preclinical research describes increased blood flow to the brain, changes in acetylcholine, serotonin and dopamine signaling, and reduced beta-amyloid in animal models.
Antioxidant activity in nerve tissue
The same review describes antioxidant protection of nerve cells through redox effects and induction of antioxidant enzymes in animal and lab studies, which may help limit oxidative damage.
Clinical trials
Meta-analysis of randomized, placebo-controlled trials of standardized Bacopa monnieri extracts dosed for at least 12 weeks without other medication, searched through June 2013, with risk of bias assessed. (Kongkeaw et al. 2014, J Ethnopharmacol)
Nine trials with 518 participants; 437 eligible participants were pooled in the meta-analysis.
Bacopa shortened Trail Making B time and choice reaction time compared with placebo, pointing to faster attention. No other pooled outcomes were reported as significant. The authors concluded Bacopa has potential to improve cognition, but that only a large head-to-head trial against an existing medication would give definitive efficacy data.
Randomized, double-blind, placebo-controlled trial of BacoMind (300 mg/day) vs placebo for 12 weeks. Outcomes: Rey Auditory Verbal Learning Test (AVLT), Rey-Osterrieth Complex Figure Test, Trail Making Test, and a memory complaint questionnaire. (Morgan et al. 2010, J Altern Complement Med)
Healthy adults over age 55; 98 started and 81 completed.
Bacopa significantly improved verbal learning, memory acquisition and delayed recall on the AVLT vs placebo. Complex Figure, memory complaint and Trail Making scores improved but did not differ significantly from placebo. Bacopa caused more digestive side effects: increased stool frequency, abdominal cramps and nausea.