Lithium and Alzheimer’s: What the Harvard Discovery Does and Doesn’t Mean

In the second half of 2025, a study from Harvard published in Nature set off one of the more remarkable waves of interest I have seen in brain-health research. The finding, distilled to a sentence, was this: a deficiency of lithium — a mineral most people associate only with high-dose psychiatric medication — may be an early and contributing factor in Alzheimer’s disease. Within weeks, “lithium orotate” supplements were selling out online.

The science here is genuinely exciting. It is also being badly misrepresented in the rush to sell supplements. Let me walk through what the research actually showed, and what it does and does not justify doing.

What the Harvard Study Found

The research team, led by Bruce Yankner, measured the levels of about two dozen metals in brain tissue from people across the spectrum from cognitively healthy to advanced Alzheimer’s disease. Lithium stood out: its levels were already reduced in people with mild cognitive impairment — the earliest symptomatic stage — and continued to fall as the disease advanced.

Crucially, some of that lithium appeared to be sequestered by amyloid plaques, effectively pulling it away from where brain cells could use it. The team then showed, in mice, that depleting lithium accelerated Alzheimer’s-like changes, and that replacing it — using a form called lithium orotate at very low doses — prevented pathology, preserved connections between neurons, and restored memory.

This Isn’t the First Hint That Lithium Matters

What makes the Harvard work compelling is that it does not stand alone. For years, population studies have hinted at a protective role for lithium at trace, naturally occurring levels. A notable Danish study found that people whose drinking water contained slightly higher levels of naturally occurring lithium had modestly lower rates of dementia. And a small randomized trial in people with mild cognitive impairment suggested that long-term low-dose lithium might slow cognitive decline.

Taken together, three independent lines of evidence — human tissue, population epidemiology, and animal experiments — now point in the same direction. That convergence is what elevates this above a single intriguing paper.

Why You Should Not Start Lithium Supplements Yet

Here is where I have to be direct, because the gap between the science and the marketing is dangerous.

We do not yet know the right dose, the right form, who would benefit, or whether supplementing lithium in humans changes any clinical outcome at all. The doses used in the mouse studies do not translate directly to people. And while the microdoses in over-the-counter lithium orotate are far lower than psychiatric doses, lithium has a narrow margin of safety — it can affect the kidneys and thyroid, and it interacts with common medications, including some blood pressure drugs and anti-inflammatories.

“A real scientific discovery and a proven treatment are not the same thing. The distance between them is measured in carefully designed human trials — and those have not yet been done for lithium in Alzheimer’s prevention.”

Those human trials are what the field needs next, and they are the reason not to self-experiment in the meantime. Buying an unregulated supplement of uncertain dose and purity, based on a mouse study, is not evidence-based prevention — it is a gamble with a mineral that requires monitoring when used medically.

What to Actually Do With This Information

If you are focused on protecting your brain, the lithium story should make you optimistic about the direction of research — not send you to a supplement retailer. The interventions that already have strong human evidence behind them have not changed: managing blood pressure and metabolic health, exercise, sleep, hearing, social and cognitive engagement, and understanding your individual genetic risk so that prevention can be tailored to it.

I am following the lithium research closely, and if well-designed human trials show a benefit, it could become a meaningful part of preventive care. Until then, the right response is patience and an evidence-based prevention plan — not a bottle of lithium orotate.

References

1. Aron L, Ngian ZK, Qiu C, et al. Lithium deficiency and the onset of Alzheimer's disease. Nature. 2025;645(8081):712-721. doi:10.1038/s41586-025-09335-x
2. Kessing LV, Gerds TA, Knudsen NN, et al. Association of lithium in drinking water with the incidence of dementia. JAMA Psychiatry. 2017;74(10):1005-1010. doi:10.1001/jamapsychiatry.2017.2362
3. Forlenza OV, Diniz BS, Radanovic M, Santos FS, Talib LL, Gattaz WF. Disease-modifying properties of long-term lithium treatment for amnestic mild cognitive impairment: randomised controlled trial. Br J Psychiatry. 2011;198(5):351-356. doi:10.1192/bjp.bp.110.080044

Published July 2026 · Medically reviewed by Nadir Bilici, MD, DipIBLM. See our editorial policy.