Before memory fades in Alzheimer’s disease, something else quietly vanishes: lithium.

A large, decades-long study shows that lithium, naturally obtained through diet, may be essential for brain health—with its deficiency potentially setting the stage for neurodegeneration.

Lithium is often linked to rechargeable batteries, but it has long been used in mood stabilizers and occurs naturally in foods.

“This is the first study to look at lithium deficiency and to show there’s natural lithium in the brain and it has a protective role,” senior researcher Dr. Bruce Yankner, a professor of genetics and neurology at Harvard Medical School, told The Epoch Times.

“We were surprised by how central lithium appears to be—it affected so many aspects of Alzheimer’s.”

In the recent study published in Nature, Yankner’s team found that lithium concentrations in the brain’s prefrontal cortex—central to memory and decision-making—drop by more than half in people with Alzheimer’s disease. This decline begins years earlier, during mild cognitive impairment, which often signals the onset of dementia.

Drawing on nearly 400 human brain samples and animal models, the researchers suggest that lithium may act like a dietary micronutrient—akin to zinc or iron—helping the brain resist aging and disease. Its loss appears to coincide with—and possibly drive—many of the earliest changes seen in Alzheimer’s disease.

Restoring lithium to healthy levels could become a way to prevent the disease before symptoms take hold, according to Yankner.

How Much Lithium Are We Talking About?

Alzheimer’s disease, which affects more than 55 million people worldwide, is defined by the buildup of amyloid plaques and tau tangles—abnormal proteins that disrupt communication between brain cells. However, these changes alone don’t always lead to memory loss. Some people with amyloid and tau lesions never develop symptoms, while others decline rapidly.

To uncover chemical changes that might help explain this gap, Yankner’s team measured 27 elements in brain and blood samples from older adults—some cognitively healthy, others with mild cognitive impairment, and others diagnosed with Alzheimer’s disease.

Lithium stood out as the only element showing a sharp, early decline in both women and men with cognitive impairment.

In healthy adults, lithium levels in the prefrontal cortex were usually between about 0.5 and 10 nanograms per gram of tissue—just a billionth of a gram. This range indicates normal levels.

In people with mild cognitive impairment, levels were about one-third lower than healthy peers. Those with Alzheimer’s showed a steeper drop—nearly 60 percent lower than in peers who had no memory problems.

Notably, blood lithium levels remained stable across all groups, indicating that the deficiency specifically targets the brain.

“These findings were so striking we didn’t believe them at first,” Yankner said. “We validated the result across multiple brain banks before we were convinced.”

Other trace metals showed either inconsistent changes or appeared only in more advanced Alzheimer’s disease.

The research revealed why lithium levels drop: amyloid plaques—the sticky protein clumps central to Alzheimer’s—bind directly to lithium and trap it. Because lithium carries a positive charge, it sticks to the negatively charged plaques like a magnet, drawing it away from neurons and other brain cells that depend on it.

As amyloid accumulates, more lithium becomes locked away in plaques, creating a vicious cycle: the more plaques, the less lithium remains available to protect brain cells. This creates what Yanker called a “lithium deprivation state,” depriving neurons of a key resource for resilience and repair.

What Happens When Lithium Runs Low

In mice, reducing lithium levels in the brain likewise resulted in Alzheimer’s-like symptoms.

In healthy aging mice, the team cut brain lithium by 50 percent through a lithium-deficient diet—same calories and nutrients as normal food, but with lithium levels reduced by 92 percent. This caused significant memory loss, increased brain inflammation, and the breakdown of synaptic connections—the communication hubs between neurons.

In mice bred to be Alzheimer’s-prone, the results were even more dramatic: Lithium deficiency accelerated the buildup of both amyloid plaques and tau tangles, the two defining features of Alzheimer’s disease.

Genetic profiling further showed that changes triggered by lithium loss closely mirrored those in the brains of people who died with Alzheimer’s.

The mechanism centers on an enzyme called glycogen synthase kinase 3 beta (GSK3beta), which lithium controls. GSK3beta drives tau pathology and neuroinflammation.

“When lithium levels drop, GSK3beta turns on, and that’s bad news for brain cells,” Yankner said. “It leads to more tangles, more plaques, and more degeneration.”

However, this lithium loss can be reversed—and with it, Alzheimer’s-like symptoms.

When researchers treated aging and Alzheimer’s-prone mice with low doses of lithium orotate—a supplement form that doesn’t get trapped in plaques like prescription lithium—they saw promising results:

• Over a year, the mice showed fewer amyloid plaques and tau tangles in the brain


• Restored memory and learning


• Reduced brain inflammation


• No signs of kidney or thyroid damage—common concerns with high-dose lithium treatments

These improvements appear to stem from lithium’s ability to suppress the overactive enzyme GSK3beta, enhance the function of microglia—the brain’s cleanup cells—and normalize gene activity involved in learning and memory.

Improvements in animal models do not always translate into humans. Many Alzheimer’s drugs have shown promise in preclinical studies but fail to reproduce the results in people.

An ‘Untapped’ Paradigm

The findings align with earlier population studies. A 2017 Danish study of more than 800,000 people found lower dementia rates in regions with naturally higher levels of lithium in drinking water. Yankner’s work may explain why.

“[These findings] represent a new direction for exploring the underlying causes of Alzheimer’s disease and point to an untapped therapeutic paradigm,” Dr. Ashley Bush, a neurologist at the University of Melbourne, noted in a commentary accompanying the study.

Yankner’s lab is now exploring whether brain imaging or blood tests could detect early lithium loss, potentially enabling preventive care long before symptoms appear.

“Just like your doctor screens for [low-density lipoprotein] LDL cholesterol to assess heart disease risk or hemoglobin A1c for diabetes, one day we might screen for lithium levels—or a related marker—to predict Alzheimer’s risk,” he said.

Bush noted that while the findings suggest that lithium may have many potential roles at the brain’s naturally low levels, its use for preventing Alzheimer’s disease has not yet been thoroughly tested in humans.

Lithium orotate is sold over the counter as a supplement in some countries, including the United States; however, the study’s authors caution against self-prescribing any lithium compound. Clinical trials are needed to test safety and efficacy in humans for Alzheimer’s disease prevention and treatment.

Natural Sources of Lithium

Although lithium has not been officially recognized as a micronutrient, it had a reputation as a wellness cure-all long before it was studied for its effects on brain health.

In the late 1800s and early 1900s, it was promoted for everything from mood balance to metabolism. Lithium salts were common in mineral “cure” waters, and the original 7-Up even contained lithium citrate—until the Food and Drug Administration banned it in 1948.

Today, most people get trace amounts of lithium from natural sources—likely enough to support brain health under normal conditions.

Lithium content varies by region, depending on local geology and soil composition, which affects how much ends up in food and drinking water. Areas with volcanic or mineral-rich terrain—such as parts of Iceland, West Texas, and Western Australia—tend to have naturally higher levels, though concentrations vary widely.

While the amounts are tiny—measured in micrograms or milligrams per day—they may be just enough to support healthy brain aging. Natural sources include:

• Drinking water, especially from groundwater or mineral-rich springs


• Vegetables such as potatoes, tomatoes, and leafy greens


• Whole grains and legumes, including beans and lentils


• Tea and certain mineral waters

For example, some bottled water brands from Germany and Italy have trace amounts of lithium—about 0.1 to 0.2 milligrams per liter—that could add to daily intake at microdose levels.

Yankner is “cautiously optimistic” that with further research, low-dose lithium could not only slow but potentially reverse early cognitive decline.

“We’re not talking about a drug,” he said. “We’re talking about a natural substance.”