When creatine gets into muscle cells, it brings sodium with it, which pulls water into the cells and makes them swell up a bit — like a sponge soaking up water.

When your cells take in creatine, they also pull in sodium, which makes the inside of the cell saltier. To balance that, water rushes in, making the cell swell up a bit.

Your muscles use a special door called SLC6A8 to let creatine in, and this door only works when there’s more sodium outside the cell than inside — like a pump that needs salt to open.

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.

Taking creatine helps your muscle cells soak up more water, making them swell a bit—and this swelling tells your body to stop breaking down muscle as much.

Creatine pulls water into your cells, making them swell a bit, and that swelling is how it helps your body work better.