There’s an enzyme in your brain that works like a “fast-forward button” on aging. It’s called GSK-3β, and lithium can slow it down by literally taking magnesium’s place inside the enzyme. Because lithium and magnesium are chemically similar, lithium slips into the spot magnesium normally sits in, and that slows down/modulates it's activity. When GSK-3β stays overactive, it shows up in Alzheimer’s and pushes neurons toward damage. Turn it down… and, theoretically, your brain cells survive longer,