What is AMPK?
AMP-activated protein kinase
AMPK is a protein that works as your cells' fuel gauge: when energy runs low, it switches on and tells the cell to burn fuel, save energy and recycle old parts.
Think of the low-fuel warning light in a car. When it comes on, you stop making unnecessary trips, look for a gas station and use what's in the tank more carefully. AMPK is that warning light inside every cell.
Why it matters for aging
AMPK senses the balance between used and available energy inside a cell. When a muscle works hard or you haven't eaten for a while, energy runs low and AMPK switches on.
Once active, it does three useful things: it helps cells take up and burn sugar and fat, it signals for new mitochondria (the cell's power plants) to be built, and it turns on autophagy, the cell's recycling system. It works as the opposite of mTOR, the cell's "grow" switch, so the two act like a seesaw between building and repairing.
A common myth
You need a supplement or drug to activate AMPK.
Exercise is one of the strongest natural AMPK activators, and fasting switches it on too. Drugs like metformin and compounds like berberine also nudge it, but they don't replace what exercise does.
Go deeper
Deep dives
- Berberine vs metformin: what the evidence actually says
- How to increase mitochondria naturally (and what's just hype)
- How long do you have to fast for autophagy? The honest answer
Related terms
Updated Nov 9, 2026 · All terms