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.

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.

When scientists lowered the sodium levels around rat muscle cells, the cells absorbed much less creatine—showing that sodium is needed for creatine to get inside these muscle cells.

Cells use a special pump to create a sodium imbalance outside and inside the cell, and that imbalance acts like a battery to help pull creatine into the cell through a specific door called SLC6A8.

When insulin is present, it tells muscle cells to pump more sodium and potassium around, which creates a better environment for the cell to pull in more creatine — a compound that helps muscles store energy.

Imagine creatine needs to get into cells through a special door that only opens one way. When creatine teams up with salt ions (sodium and chloride), the door becomes much less likely to let creatine slip back out, so it keeps moving in even when there’s already a lot of creatine inside the cell.