A protein called CRT-1 moves creatine into cells better when there's a lot of creatine inside, because it holds onto certain three-part combinations and lets go of two-part ones—kind of like a gate that only opens when the right combo is present.

For a protein called CRT-1 to let creatine out of the cell, it first needs to let go of two tiny charged particles—sodium and chloride—and it must break apart pairs of these particles, not groups of three, so the creatine doesn’t get stuck back inside.

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.

When creatine teams up with salt particles (sodium and chloride), it becomes much less likely to stick around inside the cell, so it can keep getting pulled in from outside—even when there’s already a lot of creatine inside.

CRT-1 moves creatine into cells without using a potassium battery that other similar transporters rely on, making it different from ones like the serotonin transporter.

Your body has a special door called CRT-1 that lets creatine into muscle cells by using salt particles (sodium and chloride) as helpers — it doesn’t need potassium to do this, and it can pull creatine in even when there’s already a lot inside the cell.