A new meta-analysis has found that lithium supplementation does not slow cognitive decline in older adults with Alzheimer’s disease or mild cognitive impairment. The study pooled data from six randomized, placebo-controlled trials involving 435 participants and found no significant cognitive benefit from commonly used inorganic lithium salts, such as lithium carbonate, compared with placebo. The research appears in Neuroscience and Biobehavioral Reviews.
Alzheimer’s disease is a progressive brain disorder characterised by memory loss, confusion and difficulties with daily tasks, underpinned by the accumulation of amyloid-beta plaques and tau tangles in the brain. Mild cognitive impairment represents an intermediate stage of memory decline that may precede full-blown dementia. Finding treatments that can halt or slow the transition from early memory loss to severe dementia remains a major focus of medical science.
Lithium, a naturally occurring mineral prescribed in the form of lithium carbonate to stabilise mood in bipolar disorder, has attracted attention as a potential treatment for brain protection. Laboratory work has suggested lithium might shield brain cells from damage linked to Alzheimer’s by blocking enzymes associated with disruptive protein buildup.
The history of clinical evidence has been mixed. A 2009 trial did not show major benefits from a short course of lithium on disease markers or mental decline. In 2011, another trial suggested that long‑term, low‑dose lithium could help stabilise memory and thinking in people with mild cognitive impairment. A 2015 meta-analysis of early trials offered intriguing but still inconclusive results about lithium’s protective effects.
For the current analysis, the research team led by Taro Kishi of the Fujita Health University School of Medicine sought to consolidate the latest clinical trial data into a single statistical model to assess real‑world cognitive benefits for people with mild cognitive impairment or Alzheimer’s disease. The meta-analysis targeted randomized, placebo‑controlled trials testing lithium supplementation in these populations.
The final dataset encompassed six trials, with two focusing solely on mild cognitive impairment and the remainder including various stages of Alzheimer’s disease. Study durations ranged from around 10 weeks to as long as two years, and the lithium forms used were predominantly inorganic salts, especially lithium carbonate, with some trials employing lithium sulfate or lithium gluconate.
To gauge cognitive impact, researchers relied on standard assessments such as the Alzheimer’s Disease Assessment Scale-Cognition subscale and the Mini‑Mental State Examination. Across the six trials, those receiving lithium showed no statistically significant advantage over placebo in preserving memory and thinking skills.
Secondary outcomes, including behavioural symptoms like agitation and aggression, likewise showed no meaningful improvement with lithium, and rates of withdrawal or adverse side effects were broadly similar between the lithium and placebo groups.
Subgroup analyses asked whether diagnostic category (MCI versus Alzheimer’s), study length, lithium dose, or the specific formulation altered the results. In all cases, lithium failed to demonstrate an advantage over placebo in slowing cognitive decline.
The new findings align with broader laboratory and animal research suggesting that while certain lithium compounds can influence molecular processes related to Alzheimer’s, these effects do not translate into measurable cognitive benefits for human patients when using the inorganic salts commonly studied in clinical trials.
Separately, previous PsyPost coverage noted that lithium chloride can reduce harmful protein activity and alter brain signaling in laboratory settings, a contrast with the human trial data focusing on cognitive outcomes. A September 2025 animal‑model study reported that an organic salt, lithium orotate, prevented harmful protein accumulation and improved memory, though no human trials of lithium orotate for Alzheimer’s disease exist to date.
Limitations of the meta‑analysis include its relatively small evidence base and modest participant total, which may reduce the power to detect subtle effects. Additionally, several trials diagnosed mild cognitive impairment on clinical grounds rather than modern biomarker criteria, and participants often used other anti‑dementia medications alongside lithium or placebo, potentially influencing results. The analysis concentrated on inorganic lithium salts, leaving open the possibility that organic salts might behave differently in humans, though this remains untested in clinical trials.
The study, “Lithium for Alzheimer’s disease: Insights from a meta-analysis,” was authored by Taro Kishi, Shinji Matsunaga, Youichi Saito and Nakao Iwata.
