Linkpost: "Lithium Prevents Alzheimer’s—Here’s How to Use It"

A new analysis by Jon Brudvig, published on his Substack, presents a compelling evidence-based argument for the immediate use of low-dose lithium supplements to prevent Alzheimer's disease. The post synthesizes research spanning decades, including observational studies of areas with high lithium in drinking water, data from psychiatric patients, and recent preclinical work identifying biological mechanisms. Brudvig critiques the standard academic position of waiting for randomized controlled trials (RCTs), framing the decision in terms of expected value: with a safe, low-cost intervention that could prevent an irreversible disease, inaction carries its own high risk. He argues that the existing evidence is strong enough to warrant personal action now.

The proposed effective dose is extremely low, between 0.02 and 0.3 mg per day, which is hundreds to thousands of times lower than common psychiatric doses. This puts it well below known risk thresholds. The biological mechanisms are identified: lithium inhibits the enzyme GSK-3β, which drives tau pathology, and shifts amyloid-β processing away from plaque formation. Brudvig suggests practical methods like liquid drops or taking a 1 mg pill every few days, potentially reducing individual risk by 22% or more. The post has gained traction in communities like LessWrong for its rationalist approach to health decision-making under uncertainty, challenging the default bias toward inaction in the face of promising but not-yet-definitive data.