Brahmi and bacopa: the memory claim, examined

Bacopa monnieri is used in classical Ayurveda as a medhya rasayana — a category associated with intellect and mental function — and it is among the botanicals with a reasonable body of clinical research.

The naming problem, first

The name brahmi is applied to two different plants in different regions and traditions: Bacopa monnieri and Centella asiatica, the latter also known as gotu kola.

These are unrelated plants with different constituents and different research literatures. Products labelled brahmi may contain either.

This matters for anyone trying to match a product to the research, and it is a good illustration of a general problem in herbal medicine: common names are unreliable, and the botanical name should appear on the label.

What the trials show

The research on Bacopa monnieri focuses on cognitive outcomes, and there is more of it than for most Ayurvedic botanicals.

Several randomised placebo-controlled trials in healthy adults, mostly older adults, report improvements in measures of memory — particularly delayed recall and the rate of forgetting.

Systematic reviews have generally concluded that there is some evidence for an effect on memory-related measures, with effects being small, inconsistent across the range of cognitive domains tested, and derived from trials with methodological limitations.

A consistent finding worth noting: effects appear over months rather than immediately. Trials generally run twelve weeks or longer, and shorter studies find less. This is not a substance with an acute effect.

Effects on anxiety and on attention have been examined with less consistent results.

The quality caveats

The usual ones apply. Small samples, mostly conducted in a limited number of centres, considerable variation in the extracts used, and heterogeneity in the cognitive tests employed — which makes pooling difficult and increases the chance that positive findings reflect selective reporting of the tests that reached significance.

Independent replication in large trials by groups without an institutional interest is limited.

Safety

Generally well tolerated in trials, with a specific and common issue.

Gastrointestinal effects — nausea, cramping, increased stool frequency — are the most frequently reported adverse effects and are common enough to be a practical limitation. Taking it with food reduces this for some people.

Thyroid. Some animal research suggests bacopa may increase thyroid hormone levels. Anyone with thyroid disease or on thyroid medication should discuss it with a doctor.

Sedative interactions. Possible additive effects with sedating medication.

Anticholinergic and cholinergic medication. Proposed cholinergic activity raises theoretical interaction concerns.

Pregnancy and breastfeeding. Insufficient data; avoidance is the standard advice.

Product variability and contamination, as with all herbal products. See our article on heavy metals in traditional medicines.

The reasonable assessment

There is more evidence here than for most traditional cognitive preparations, and it is not strong evidence.

The pattern — small effects on specific memory measures, appearing over months, in trials with real limitations — is consistent with either a genuine modest effect or with the accumulated bias one would expect from a literature of small studies.

It is not a treatment for dementia or for cognitive decline, and it should not be used as one. Anyone with genuine memory concerns needs medical assessment, since reversible causes exist and identifying them matters.

What has better evidence for cognition

Worth stating, because the comparison is instructive.

Physical exercise has the strongest evidence of any modifiable factor for cognitive function in older adults. Sleep quality matters substantially. Cardiovascular risk factor management — blood pressure, diabetes, smoking, lipids — has good evidence for reducing dementia risk. Hearing loss correction is associated with reduced risk. Social engagement and education are consistently associated with better outcomes.

These are not exciting and they have vastly better evidence than any supplement, and anyone concerned about cognition should attend to them first.

New or worsening memory problems require medical assessment. Do not use supplements in place of investigation. Discuss any supplement with your doctor if you have thyroid disease or take prescribed medication.