Berberine is an alkaloid found in many species of the plant genus Berberis, as well as shrubs and trees in the poppy and cork families. Berberine might help to manage diabetes, high cholesterol, and high blood pressure for some people, but there is currently no clinical evidence that it can prevent cognitive decline or dementia. While berberine may be safe for short-term use, it interacts dangerously with some medications and evidence for long-term safety is lacking.
No studies have specifically tested whether berberine can affect human cognitive function or prevent dementia.
Our search identified:
• Numerous preclinical studies
There is no clinical evidence that berberine prevents cognitive decline or Alzheimer's disease. Preliminary evidence from clinical trials suggests that it can help to manage type 2 diabetes, high cholesterol, and high blood pressure . Because these conditions raise the risk of poor brain health in old age, managing them may indirectly help promote better long-term cognitive health  but other available therapies may be more effective and reliable.
Preclinical evidence on berberine shows both benefit and harm. Several experiments suggest berberine may promote cognitive function , protect neurons by inhibiting an enzyme that produces toxic beta-amyloid? , and reduce brain inflammation . In contrast, other experiments suggest that berberine treatment may accelerate the death of brain cells when started after damage has occurred, such as in Parkinson’s disease , hypoxia (low oxygen) , and neurotoxin exposure . Brain aging alone can lead to damage that may, in theory, be worsened by berberine depending on the timing of treatment. None of these effects on the brain, positive or negative, have been confirmed in human studies yet.
No clinical studies have tested whether berberine benefits patients with dementia. Some preclinical studies have shown that berberine has protected against certain aspects of Alzheimer's disease related to beta-amyloid , tau, and brain inflammation . However, other studies suggest that berberine may accelerate neuronal death in the presence of damage [7-10]. None of these potentially beneficial or harmful effects have been confirmed in human studies.
Berberine is regarded as safe for consumption for most healthy adults , though no studies have examined its long-term safety. Caution should be taken when combining prescription medications with berberine, and it should not be taken with cyclosporine . New preclinical evidence raises concerns about possible risks of cancer, brain toxicity, and dangerous interactions with other drugs . Women who are pregnant or breastfeeding should not take berberine, as it may cross the placental barrier and pass into breast milk, with possibly severe risks to the fetus or infant . During short-term use, common side effects include nausea, diarrhea, constipation, abdominal distension, and abdominal pain.
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
Berberine is commercially available as a dietary supplement. It is isolated from roots, rhizomes, stems, and bark of plants from the genus Berberis, most commonly Berberis vulgaris or barberry. Commercial extracts vary in content, depending on the species of plant and the extraction method —and the content of many species has not yet been fully evaluated. Berberine is a component of Goldenseal, an herb marketed to promote immune health. It is critical to consult with your physician before taking berberine, given its potential to interfere with other medications .
Information on safety, doses, and drug interactions from MedlinePlus
Evaluation of berberine's potential biological effects from Examine.com