Every spring, as exams approach, searches for bacopa soar. This Ayurvedic plant, Bacopa monnieri, is among the most studied for memory. But trials say less than the promises surrounding it: modest effects on certain tests after eight to twelve weeks, with uneven results. Here is what they measured, in whom, at what dose, and what to know about tolerability.
Key takeaways
- In most trials, bacopa was taken for 12 weeks at 300mg of standardised extract per day.
- Three meta-analyses, three conclusions: slightly faster attention, no clear effect, or better working memory at a high dose, a finding requiring confirmation.
- In a small trial, a single 300mg dose did not change any test two hours later; most reported effects require weeks.
- Adverse effects are mainly digestive, and no health claim is authorised for bacopa in the European Union.
Bacopa monnieri: what is this plant?
Bacopa (Bacopa monnieri) is a small, creeping perennial of wetlands: pond banks, marshes and waterways. It grows particularly in India, Sri Lanka and Australia.
In India it is called brahmi. Ayurvedic medicine classifies it among “medhya rasayana”, plants supposed to sharpen memory and intellect, and also used it against epilepsy and anxiety.
Bacosides and standardised extracts: what are they?
The most studied compounds are bacosides, saponins present in the leaves and stems. “Bacoside A”, their main fraction, is a mixture of four molecules that enters the blood poorly because it does not dissolve in water.
Trials use standardised extracts with measured bacoside contents, whose composition varies considerably: around 5% saponins in a Thai trial's extract, and nearly 38% bacoside A in a methanol extract. A result obtained with one, often commercial, extract therefore does not necessarily apply to another.
How might bacopa act on the brain?
Proposed mechanisms mainly come from animal and cell studies. Extracts show antioxidant activity, inhibit beta-amyloid protein aggregation and inhibit acetylcholinesterase, the enzyme that breaks down acetylcholine, a memory messenger made from choline.
In humans, a Thai trial observed lower activity of this enzyme in the blood of treated older people. Inhibiting it is also an approach studied for huperzine A. These hypotheses alone do not prove an effect on memory.
Bacopa and memory: what do trials in healthy adults show?
Effects on some tests, not all, and not in every trial. In an Australian trial, 46 adults aged 18 to 60 took 300mg of extract or a placebo for 12 weeks. The bacopa group improved visual processing speed, learning speed and recall of a word list, and its anxiety decreased.
Conversely, an Indian trial in 72 adults aged 35 to 60 taking 450mg per day for 12 weeks found no difference from placebo for either memory or attention. Only a trend towards less anxiety appeared.
What do trials in older people show?
Three 12-week trials involved older people without dementia. In the United States, among 54 people aged 65 or over, 300mg per day improved delayed word-list recall, the primary outcome, and a selective attention test; anxiety and depression scores decreased.
In Australia, among 98 people over 55, the same dose improved learning and delayed recall of a word list. In Thailand, among 60 older people, 300 and 600mg improved working memory and attention. The anxiety effect observed in the United States was not found in the Indian trial, which used the same questionnaire.
The main trials in one table
| Trial | Participants | Dose and duration | Main result |
|---|---|---|---|
| Stough, 2001 (Australia) | 46 adults aged 18 to 60 | 300mg/day, 12 weeks | Improved learning and processing speed |
| Sathyanarayanan, 2013 (India) | 72 adults aged 35 to 60 | 450mg/day, 12 weeks | No difference from placebo |
| Calabrese, 2008 (United States) | 54 people aged 65 or over | 300mg/day, 12 weeks | Improved delayed word recall |
| Morgan, 2010 (Australia) | 98 people over 55 | 300mg/day, 12 weeks | Improved verbal learning, digestive complaints |
| Peth-Nui, 2012 (Thailand) | 60 older people (mean age 62) | 300 or 600mg/day, 12 weeks | Improved working memory and attention |
| Nathan, 2001 (Australia) | 38 healthy adults | 300mg, single dose | No effect after 2 hours |
What do meta-analyses conclude?
Their conclusions disagree. In 2014, a meta-analysis of 9 trials with 518 participants lasting at least 12 weeks concluded that attention was faster: choice reaction time was around 10 milliseconds shorter, and an attention and flexibility test, Trail Making Test B, was completed faster. The authors considered the trials good quality, but called for a large trial comparing bacopa with an existing medicine.
A 2021 analysis of 11 trials is more cautious. Once results were pooled, delayed recall and learning speed did not differ significantly from placebo, with high heterogeneity (I² 84 to 93%). According to the authors, most trials find effects on only one or two tests, rarely the same between studies. Using numerous tests increases the risk of positive findings arising by chance.
In 2026, a network meta-analysis of 29 trials with 2,107 healthy adults indirectly compared bacopa with ginkgo. From 600mg per day, bacopa outperformed placebo and ginkgo for working memory, without an effect on attention or processing speed. This very large difference is unusual for a food ingredient. It rests on indirect comparisons and needs confirmation.
How long does it take to observe an effect?
Several weeks. In the 2001 Australian trial, effects were more evident at 12 weeks than at 5 weeks. In the Thai trial, some memory and attention scores improved from 4 weeks, others at 8 weeks, and some effects persisted 4 weeks after stopping.
Single-dose trials disagree: two hours later, 300mg had no effect in 38 volunteers, while 320 or 640mg improved two tasks in 17 others. Relying on a capsule the day before an exam therefore has no firm basis.
Which doses have been studied?
The most tested dose is 300mg of standardised extract per day; some trials used 450 or 600mg. Usual doses range from 300 to 600mg of extract, equivalent to 5 to 10 g of dried plant.
Dose is not everything: the Thai trial showed effects at both 300 and 600mg, while the Indian trial found none at 450mg. The advantage suggested in 2026 for doses of at least 600mg was not seen in the Thai trial, which directly compared 300 and 600mg.
What studies do not yet tell us
- Children. A 2016 review identified only five studies, with effect sizes calculated only from significant results; the authors called for replicated trials. Attention-deficit/hyperactivity disorder (ADHD) requires a doctor.
- The long term. Most trials last 12 weeks: the value and safety of taking it for years are unknown.
- Comparisons. Bacopa and ginkgo have never been directly compared, and it is unknown how bacopa compares with other ingredients studied for memory, such as magnesium L-threonate.
What side effects and precautions apply?
In trials, bacopa is generally well tolerated, with no serious adverse effect reported.
Digestive complaints
In people over 55, it caused more frequent stools, abdominal cramps and nausea than placebo, and more withdrawals. In the American trial, however, adverse effects, mostly stomach upset, were just as numerous with placebo. Dry mouth, fatigue and flu-like symptoms are rarer.
Trials do not tell us whether it should be taken fasting or with a meal; taking it with food is simply a common-sense precaution.
Thyroid, pregnancy and breastfeeding
In mice, a leaf extract at 200mg per kilogram increased thyroxine (T4), a thyroid hormone, by 41%. Whether this occurs in humans is unknown, but medical advice is essential with hyperthyroidism or thyroid treatment. Our article on iodine deficiency explains this gland's role.
No clinical study has assessed its safety during pregnancy or breastfeeding; many researchers discourage it.
Medicine interactions
In the laboratory, the extract inhibits several cytochrome P450 enzymes that eliminate many medicines. A patient taking cevimeline, a cholinergic medicine, developed sweating, nausea and a faster heartbeat after a supplement containing bacopa. In a Polish analysis of 1,816 adverse-event reports, two cases were attributed to a probable interaction with an antidepressant: back pain and sweating with agomelatine, and myocardial infarction with moclobemide.
If you take medication, especially an antidepressant or an Alzheimer's medicine acting on acetylcholine, or if your heart beats slowly, seek advice from a doctor or pharmacist.
Frequently asked questions
Bacopa, brahmi and garden bacopa: are they the same plant?
Brahmi is the Indian name for Bacopa monnieri, but in some Indian regions also refers to centella (Centella asiatica), leading to labelling errors: only the Latin name is reliable. The “bacopa” in planters is another species, Chaenostoma cordatum, native to South Africa.
Should you take bacopa in the morning or evening?
No trial has compared timing. Since effects were measured after weeks of daily use, regularity matters more than the hour. Choosing a fixed time helps avoid forgetting it.
Does bacopa lower blood pressure?
In the American trial in people over 65, blood pressure did not change, but heart rate fell with bacopa while rising with placebo. If you take medication for blood pressure or your heart, discuss it with your doctor.
Does bacopa help you sleep?
The trials cited here did not measure sleep. Ayurveda used it against insomnia, an unproven traditional use. For disturbed sleep, see our article on melatonin and sleep.
Can bacopa and ashwagandha be combined?
These two Ayurvedic plants sometimes appear in the same formulas. But in trials of mixtures, the effect cannot be attributed to bacopa alone, and the Polish analysis cited above implicates both plants in interactions with antidepressants. See also our article on ashwagandha.
How useful are reviews of bacopa?
A testimonial cannot separate a plant's effect from a placebo effect, hence double-blind trials. In people over 55, participants' own assessment of memory did not differ from placebo, while some tests improved: a measured gain is not always perceived.
Can bacopa be sold as a food supplement?
Yes. In the European Union it is not a “novel food” when used in supplements, and France permits it under the order of 24 June 2014. But no health claim is authorised for it. Only certain nutrients have official wording, such as “zinc contributes to normal cognitive function”.
Conclusion
Bacopa is one of the most studied plants for memory, but measured trial effects remain modest and inconsistent: improvements in some memory and attention tests, most often after 12 weeks of daily 300mg standardised extract.
It is generally well tolerated apart from digestive complaints, with precautions for the thyroid, pregnancy, breastfeeding and ongoing treatments. Sleep, self-testing and physical activity remain the best-supported methods for memory.
Sources
- Kongkeaw C et al. (2014). Meta-analysis of randomized controlled trials on cognitive effects of Bacopa monnieri extract. Journal of Ethnopharmacology, 151(1), 528-535. doi:10.1016/j.jep.2013.11.008
- Brimson JM et al. (2021). The effectiveness of Bacopa monnieri (Linn.) Wettst. as a nootropic, neuroprotective, or antidepressant supplement: analysis of the available clinical data. Scientific Reports, 11(1), 596. doi:10.1038/s41598-020-80045-2
- Tiemtad P et al. (2026). Comparative effects of Bacopa monnieri and Ginkgo biloba on cognitive functions: A systematic review and network meta-analysis. Phytomedicine, 153, 157915. doi:10.1016/j.phymed.2026.157915
- Stough C et al. (2001). The chronic effects of an extract of Bacopa monniera (Brahmi) on cognitive function in healthy human subjects. Psychopharmacology, 156(4), 481-484. PMID 11498727
- Sathyanarayanan V et al. (2013). Brahmi for the better? New findings challenging cognition and anti-anxiety effects of Brahmi (Bacopa monniera) in healthy adults. Psychopharmacology, 227(2), 299-306. doi:10.1007/s00213-013-2978-z
- Calabrese C et al. (2008). Effects of a standardized Bacopa monnieri extract on cognitive performance, anxiety, and depression in the elderly: a randomized, double-blind, placebo-controlled trial. Journal of Alternative and Complementary Medicine, 14(6), 707-713. doi:10.1089/acm.2008.0018
- Morgan A, Stevens J (2010). Does Bacopa monnieri improve memory performance in older persons? Results of a randomized, placebo-controlled, double-blind trial. Journal of Alternative and Complementary Medicine, 16(7), 753-759. doi:10.1089/acm.2009.0342
- Peth-Nui T et al. (2012). Effects of 12-Week Bacopa monnieri Consumption on Attention, Cognitive Processing, Working Memory, and Functions of Both Cholinergic and Monoaminergic Systems in Healthy Elderly Volunteers. Evidence-Based Complementary and Alternative Medicine, 2012, 606424. doi:10.1155/2012/606424
- Nathan PJ et al. (2001). The acute effects of an extract of Bacopa monniera (Brahmi) on cognitive function in healthy normal subjects. Human Psychopharmacology: Clinical and Experimental, 16(4), 345-351. doi:10.1002/hup.306
- Kean JD, Downey LA, Stough C (2016). A systematic review of the Ayurvedic medicinal herb Bacopa monnieri in child and adolescent populations. Complementary Therapies in Medicine, 29, 56-62. doi:10.1016/j.ctim.2016.09.002
- Gościniak A et al. (2025). Bacopa monnieri: Preclinical and Clinical Evidence of Neuroactive Effects, Safety of Use and the Search for Improved Bioavailability. Nutrients, 17(11), 1939. doi:10.3390/nu17111939
- Benson S et al. (2014). Acute effects of 320mg and 640mg of a standardised Bacopa monnieri extract on multitasking stress reactivity and mood: a double-blind placebo-controlled crossover trial. Phytotherapy Research, 28(4), 551–559. doi:10.1002/ptr.5029
- Siwek M et al. (2023). Harder, better, faster, stronger? Retrospective chart review of adverse events of interactions between adaptogens and antidepressant drugs. Frontiers in Pharmacology, 14, 1271776. doi:10.3389/fphar.2023.1271776
- Suksawat M et al. (2025). Integrated microscopic, HPTLC, and HRM analyses for differentiating Centella asiatica (L.) Urb., Bacopa monnieri (L.) Wettst, and Hydrocotyle umbellata L. Scientific Reports, 15(1), 21370. doi:10.1038/s41598-025-06188-2
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