Protocol
Bacopa monnieri standardized extract 300–450 mg/day
The pooled chronic trials (Kongkeaw 2014, PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 24252493, 9 trials, 518 adults) used standardized extracts at 300 to 450 mg/day for 12 weeks or longer and improved two measures, Trail B time and choice reaction time; the protocol is named for that dose.
Grade C: human trials exist, but they are small, mixed or not yet repeated. This is not a finding that it does not work. How to read a grade →
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How this letter has changedLatest: October 2026 · Corrected.
The protocol was named for 600 mg or more at 55 percent bacosides. The pooled chronic trials (Kongkeaw et al., J Ethnopharmacol, 2014; PMID 24252493; 9 trials) used 300 to 450 mg/day, the only chronic 600 mg trial (Peth-Nui et al., 2012; PMID 23320031) used a 5 percent saponin extract, and the 600 mg advantage in Tiemtad et al. (Phytomedicine, 2026; PMID 41678913) is an indirect network comparison. The written B and C attach to the dose and form the trials used, so the name now reads Bacopa monnieri standardized extract 300 to 450 mg/day. The letter stays C: pooled gains on two measures against a null 2025 trial of 300 mg (Lopresti et al., 2025; PMID 41091332) is mixed evidence. The three options on the decision sheet collapse to this one under the rule. Applied the written grade definition under the editor's standing instruction of October 2026 (Arnold Sandlow, D.C.).PMID 23320031 PMID 24252493 PMID 41091332 PMID 41678913
The description claimed broad cognitive improvement at 600 mg plus from pooled trials that used 300 to 450 mg/day and improved two measures, and said the lack of a hard endpoint An outcome that matters directly to a person and is counted without judgment, such as death, heart attack, stroke or fracture. is why the letter is not A, which is not the site's rule. Rewritten to what Kongkeaw 2014 (PMID 24252493), Pase 2012 (PMID 22747190) and Tiemtad 2026 (PMID 41678913) show. Added Downey 2013 (PMID 23281132): acutely, 320 mg improved performance and 640 mg did not. Morgan 2010 (PMID 20590480) added for its result and its gastrointestinal side effects, also seen in Lopresti 2025 (PMID 41091332). The not-replicated flag stands for the 600 mg plus dose. Letter unchanged; the name is on the editor's list.PMID 24252493 PMID 22747190 PMID 41678913 PMID 23281132 PMID 20590480 PMID 41091332
The Bacopa 600 mg+ protocol held a B on meta-analyses A study that pools the numbers from several trials into one combined estimate. whose trials mostly used 300 to 450 mg/day (Kongkeaw et al., J Ethnopharmacol 2014; PMID 24252493; Pase et al., J Altern Complement Med 2012; PMID 22747190). The only chronic trial at 600 mg/day (Peth-Nui et al., Evid Based Complement Alternat Med 2012; PMID 23320031) used a 5 percent saponin extract, and a recent trial was null (Lopresti et al., Clin Drug Investig 2025; PMID 41091332). At the named dose this is C. Editor adjudication, October 2026.PMID 24252493 PMID 22747190 PMID 23320031 PMID 41091332
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This protocol is bacopa, an herb from India, at 300 to 450 mg a day for memory and thinking. In studies of daily use, it improved two tests: one of mental speed and one of reaction time. A 2025 study of 300 mg in 101 adults found no gain on any main test. The idea that 600 mg or more works better rests on an indirect comparison and one study of a different extract.
The pooled chronic trials (Kongkeaw 2014, PMID 24252493, 9 trials, 518 adults) used standardized extracts at 300 to 450 mg/day for 12 weeks or longer and improved two measures, Trail B time and choice reaction time; the protocol is named for that dose. The case for 600 mg/day or more rests on an indirect network comparison (Tiemtad 2026, PMID 41678913) and the only chronic 600 mg trial used a 5 percent saponin extract, so the earlier name, 600 mg at 55 percent bacosides, matched no trial. A 2025 trial of 300 mg in 101 adults was null on every primary cognitive outcome. Objective cognitive tests, not self-report; the limits are inconsistent results, not the absence of a hard endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score..
Why this gradeGrade C, small or unreplicated trials. The reasoning, and what the grade does not cover.
Grade C on objective cognitive tests. The pooled chronic trials used 300 to 450 mg/day and improved two measures, Trail B time and choice reaction time (Kongkeaw et al., 2014; PMID 24252493; 9 trials, 518 adults). The case for 600 mg/day or more rests on an indirect network comparison (Tiemtad et al., 2026; PMID 41678913), and the only chronic 600 mg trial used a 5 percent saponin extract (PMID 23320031). A 2025 trial of 300 mg in 101 adults was null on every primary outcome (PMID 41091332). The protocol was renamed in October 2026 from 600 mg at 55 percent bacosides, a dose and extract no cited chronic trial tested, to the standardized extract at 300 to 450 mg/day the pooled trials used.
WHAT THIS GRADE DOES NOT COVERcognition broadly, dementia prevention, doses of 600 mg/day or more, which rest on an indirect comparison and a single trial of a different extract, or any specific bacoside percentage, which the pooled trials did not standardize to one value.
A grade describes the human evidence for a named use. It is not advice, and it is not a judgment on any individual prescription. How the letters are decided →
The evidence, in fullSeven papers, each linked to its PubMed record.
Kongkeaw et al. (J Ethnopharmacol, 2014; PMID 24252493): meta-analysis of 9 randomized trials (518 adults), 12 weeks or longer; improvement on Trail B (-17.9 ms) and choice reaction time, not across cognition broadly. Pase et al. (J Altern Complement Med, 2012; PMID 22747190): systematic review A review that searches for every study on a question using a method set in advance, then assesses them together. of 6 trials, all 12 weeks at 300 to 450 mg/day, benefit mainly in free recall. Tiemtad et al. (Phytomedicine, 2026; PMID 41678913): network meta-analysis of 29 trials; the working-memory advantage of 600 mg/day or more is an indirect comparison and the authors note the lack of direct comparisons. Peth-Nui et al. (Evid Based Complement Alternat Med, 2012; PMID 23320031): the only chronic trial at 600 mg/day, 60 healthy older adults, 12 weeks, working memory and event-related potentials improved, extract standardized to 5 percent saponins, not 55 percent bacosides. Downey et al. (Phytother Res, 2013; PMID 23281132): acute crossover A trial design in which each participant receives both the treatment and the comparison, one after the other, and serves as their own control. in 24 adults, 320 mg improved performance on the cognitive demand battery and 640 mg did not. Null: Lopresti et al. (Clin Drug Investig, 2025; PMID 41091332), 101 adults aged 40 to 70 with memory complaints, 300 mg/day for 12 weeks, no between-group difference on verbal learning, attention or working memory; the first author directs a contract research organization funded by nutraceutical companies. Safety: Morgan and Stevens (J Altern Complement Med, 2010; PMID 20590480), 98 adults over 55, 300 mg/day improved verbal learning and recall but caused increased stool frequency, abdominal cramps and nausea; digestive complaints were also more frequent on Bacopa in Lopresti 2025. Grade C for the 600 mg plus dose as named: one chronic trial at that dose, in a different extract, plus an indirect estimate.
The Rey Auditory Verbal Learning Test (RAVLT) or a validated online cognitive battery at baseline and 12 weeks: the trials in the Pase 2012 review (PMID 22747190) all ran 12 weeks. Working memory and processing speed specifically, as these showed the most consistent effects. Response is unlikely before 8 weeks; the mechanism involves dendritic branching rather than acute neurotransmitter effects.
Evidence notes: meta-analysis, not independently replicated The same finding reproduced by a separate research group. A result seen once can be chance or bias; a replicated one is harder to explain away.
Endpoint graded: Objective cognitive test performance (functional)
Last reviewed: July 2026
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bacopa[tiab] AND (cognit*[tiab] OR memory[tiab]) AND (randomized controlled trial[pt] OR meta-analysis[pt])Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →