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A recent meta-analysis evaluating the cognitive effects of lithium supplementation in older adults found that the mineral does not slow cognitive decline in individuals with Alzheimer’s disease or mild cognitive impairment. The research provides evidence that commonly prescribed forms of lithium are not effective at preserving memory and thinking skills in this population. The findings were published in the Neuroscience and Biobehavioral Reviews.
Alzheimer’s disease is a progressive condition of the brain where brain cells gradually degrade and die, leading to worsening memory, confusion, and an inability to perform daily tasks. The disease is characterized by the accumulation of harmful proteins in the brain, namely amyloid-beta plaques and tau tangles, which disrupt cell communication and cause inflammation. Before a person develops full Alzheimer’s disease, they often experience mild cognitive impairment, an intermediate stage of memory loss that is noticeable but does not completely disrupt everyday life. Finding treatments that can halt or slow this progression from early memory loss to severe dementia is a major priority in medical science.
One substance that has attracted attention as a potential treatment is lithium. Lithium is a naturally occurring mineral that is most commonly formulated as a medication, such as lithium carbonate, to stabilize mood in people with bipolar disorder. In recent years, laboratory experiments have suggested that lithium might also protect brain cells from the damage seen in Alzheimer’s disease by blocking specific enzymes that lead to protein buildup.
A series of small clinical trials and earlier pooled reviews yielded mixed evidence on whether lithium can actually slow cognitive decline in humans. For example, a 2009 clinical trial investigated whether a short course of lithium could alter disease markers and slow mental decline in patients with Alzheimer’s, but it found no major benefit.
A few years later, a 2011 clinical trial indicated that long-term, low-dose lithium treatment helped stabilize memory and thinking in patients with mild cognitive impairment. Trying to make sense of these varying outcomes, a 2015 meta-analysis combined the results of these early clinical trials, yielding intriguing but still inconclusive evidence about the mineral’s protective effects.
This conflicting background set the stage for an updated analysis of lithium’s therapeutic value in Alzheimer’s disease. The research team, led by Taro Kishi of the Fujita Health University School of Medicine, wanted to incorporate the most recent clinical trials into a single, comprehensive statistical model to see if lithium offers any reliable cognitive benefits for people with mild cognitive impairment and Alzheimer’s disease.
To explore this question, the scientists utilized a meta-analysis, which is a statistical method that pools data from multiple independent studies to identify broader trends that a single study might miss. The researchers searched major scientific databases for randomized, placebo-controlled trials that tested lithium supplementation in individuals diagnosed with mild cognitive impairment or Alzheimer’s disease. In these types of trials, one group of patients receives the active medication while another receives an inactive dummy pill, allowing researchers to isolate the effects of the drug.
The final analysis included six clinical trials with a total of 435 participants. Two of the trials focused exclusively on patients with mild cognitive impairment, while the others included patients with various stages of Alzheimer’s disease. The length of the studies varied, with some tracking patients for just 10 weeks and others following them for up to two years. The types of lithium used in these trials were mostly inorganic salts, predominantly lithium carbonate, though some used lithium sulfate or lithium gluconate.
To measure cognitive changes, the original studies used standardized tests such as the Alzheimer’s Disease Assessment Scale-Cognitive Subscale and the Mini-Mental State Examination. These tools are questionnaires and tasks designed to evaluate memory, language, attention, and basic problem-solving skills. The research team compared the cognitive test scores of the patients who took lithium with those who took a placebo to determine if the mineral slowed their rate of mental decline.
The researchers found that lithium supplementation was not better than a placebo at preserving cognitive function. When combining the data from all six studies, the difference in cognitive test scores between the lithium group and the placebo group was not statistically significant. The patients taking lithium experienced a similar rate of memory and thinking decline as those who did not receive the treatment.
The team also looked at secondary outcomes, including behavioral symptoms like agitation and aggression, which are common in advancing Alzheimer’s disease. Once again, the results were not statistically significant; lithium did not improve behavioral symptoms better than a placebo. Similarly, the rates of people dropping out of the studies or experiencing adverse side effects were roughly equal between the lithium and placebo groups.
To ensure they were not missing specific scenarios where lithium might work, the scientists performed several subgroup analyses. They checked whether the results differed depending on the patient’s diagnosis, the length of the study, the dose of lithium, or the specific formulation used. In all of these categories, lithium consistently failed to show an advantage over the placebo.
These findings are in line with research covered by PsyPost in May 2026, which found that lithium chloride treatment reduced harmful protein activity and altered brain signaling. However, the new meta-analysis evaluated clinical cognitive outcomes in human patients rather than molecular and cellular changes in laboratory cell cultures.
The results also offer interesting context for another study covered by PsyPost in September 2025. That study, which used mouse models rather than human clinical trials, found that treatment with a specific organic salt called lithium orotate prevented harmful protein accumulation and improved memory. While those animal and cellular studies suggest lithium has biological effects on Alzheimer’s mechanisms, the new study indicates that the specific inorganic lithium salts commonly used in human clinical trials, such as lithium carbonate, do not translate into measurable cognitive benefits for human patients.
As with all research, there are some caveats to consider. The meta-analysis was based on a relatively small number of studies and a modest total of 435 participants, which limits the statistical power of the analysis. A larger pool of data might be needed to detect very subtle effects. There are also a few things to keep in mind regarding the participants themselves. In the older trials, patients with mild cognitive impairment were diagnosed based on clinical symptoms rather than modern biological markers like brain scans or spinal fluid tests. This means some participants might have had memory issues caused by conditions other than early Alzheimer’s disease.
Additionally, the patients in these trials were often taking standard anti-dementia medications alongside the lithium or placebo. The types and combinations of these medications varied across the studies, which might have influenced the outcomes. Finally, the analysis focused heavily on inorganic lithium salts like lithium carbonate and lithium sulfate. Some researchers suggest that organic salts like lithium orotate might enter brain cells more efficiently and with fewer side effects, but human clinical trials testing lithium orotate for Alzheimer’s disease are currently lacking.
The study, “Lithium for Alzheimer’s disease: Insights from a meta-analysis,” was authored by Taro Kishi, Shinji Matsunaga, Youichi Saito, and Nakao Iwata.