Evidence of an intracellular creatine-sensing mechanism that modulates creatine biosynthesis via AGAT expression in human HAP1 cells

Your muscles need sodium to pull in creatine, kind of like a battery-powered door — if the battery's dead or there's no sodium around, creatine can't get inside, even if you're drinking plenty of water.

In certain human cells, the more creatine builds up inside, the less the cell makes on its own — like a built-in thermostat that senses creatine levels and turns down production when there's enough.

Creatine gets into human cells in two ways: one is like a precise lock-and-key system that works well at low levels, and the other is a more general process that kicks in when there's a lot of creatine around.

In certain human cells, how much creatine is inside the cell controls a specific gene switch, no matter how the creatine got in—meaning the cell cares about its internal supply, not where it came from.

Scientists made a tool in lab-grown cells that lights up when creatine is present, so they can quickly test how well different drugs or substances affect creatine levels inside cells.

Your body makes creatine on its own and adjusts how much it makes based on how much energy your cells need, helping shuttle energy where it's needed most.