A recent study published in Nature by Harvard Medical School researchers is making waves in the neuroscience community. Read the paper here.

The research suggests that lithium deficiency in the brain may be an early driver of Alzheimer’s disease (AD). Scientists found that people with mild cognitive impairment (MCI) and AD had significantly lower lithium levels in their brains compared to healthy individuals. This challenges the long-standing view that amyloid plaques alone are the main cause of AD and opens the door to new possibilities for prevention and treatment.

Why Lithium Matters for the Brain

Lithium is best known as a prescription treatment for mood disorders. But at very low doses—far lower than psychiatric treatment levels—it appears to play an important role in brain health.

Here’s what the latest research shows:

• Lithium levels are lower in affected brain areas. Tissue from people with Alzheimer’s showed less lithium in damaged regions compared to healthier areas.
  
• Lithium gets trapped. In people with MCI, lithium was already being pulled into amyloid plaques, leaving too little “free” lithium to protect the brain.
  
• The same happens in mice. Animals fed a lithium-depleted diet developed more plaques and worse memory problems. But when given microdoses of lithium orotate—just 1/1000th the level used for mood disorders—their memory improved and brain damage was reduced.

This creates a vicious cycle: less lithium → more plaques → even less lithium.

The Dosing Paradox

Therapeutic doses of lithium for bipolar disorder are much higher than the levels that appear to protect the brain. At **microdoses—up to 1000x lower than psychiatric treatment levels—**lithium shows neuroprotective effects with minimal side effects.

This suggests lithium may work through different mechanisms at different doses.

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How Lithium Protects the Brain

Researchers believe lithium helps the brain in several important ways:

• Blocks harmful proteins. Lithium inhibits GSK3β, a protein that drives both tau tangles and amyloid plaque buildup.
  
• Reduces inflammation. It calms damaging brain inflammation linked to memory decline.
  
• Supports resilience. Lithium may strengthen neurons and help them function longer.
  
  

Population studies support this idea, too. Data published in JAMA Psychiatry shows that areas with naturally higher lithium in drinking water—such as parts of Texas, Nevada, Japan, Chile, and Argentina—tend to have lower dementia rates.

Why Previous Trials Were Mixed

Earlier clinical trials often used lithium carbonate, the same form prescribed for mood conditions. But we now know this form can get trapped inside amyloid plaques, reducing its effectiveness. The new research suggests that lithium orotate may remain more active in the brain, explaining the more promising results in animal models.

What This Means Clinically

While the findings are compelling, it’s important to emphasize: we’re not ready for lithium supplementation yet.

Key unknowns include:

• The optimal dose for brain protection
  
• How long supplementation would need to continue
  
• Which patients are most likely to benefit
  
  

Current Lithium Sources

• Natural drinking water in some regions
  
• Certain mineral waters
  
• Foods grown in lithium-rich soil
  
  

Why This Matters

Lithium is inexpensive, widely available, and already has a well-understood safety profile. If confirmed in clinical trials, it could become one of the most accessible prevention tools we have for Alzheimer’s.

What’s Next

Several human clinical trials are now being designed, with results expected in the next 3–5 years. These studies will determine whether low-dose lithium can truly help prevent or slow Alzheimer’s in people at risk.

What Patients Should Know

• Promising, but not proven. Most strong evidence so far comes from animal studies and population data, not large-scale human trials.
  
• Not the same as prescription lithium. The doses under study are far lower and carry far fewer side effects.
  
• Don’t start supplementation on your own. If you’re interested, talk with your doctor about evidence-based prevention strategies.
  
  

The Takeaway

Lithium may be more than just a psychiatric medicine—it could be a vital mineral for brain health. But we’re still in the early stages. The science is encouraging, and if clinical trials confirm its benefits, lithium could become a simple, low-cost way to help protect memory as we age.

At Sunday Health, we’re cautiously optimistic and will continue to follow this research closely—sharing updates as new evidence emerges.