Acetylcholine

Acetylcholine is a tiny chemical messenger in your body that helps your nerve cells communicate with muscles and other cells. When a nerve wants to tell a muscle to move, it releases acetylcholine. This chemical then travels to the muscle and makes it contract (squeeze) or relax. This is how your brain tells your muscles what to do, like when you want to lift your arm or smile. Acetylcholine is a key player in controlling your muscles and many other important processes in your body.