Our body's primary source of potassium is:

The primary source of potassium in the body is the intracellular fluid. Potassium is predominantly found inside the cells, where it plays a crucial role in various physiological processes, including maintaining cellular membrane potential, contributing to nerve impulse transmission, and regulating muscle contractions. The intracellular concentration of potassium is substantially higher than that in the extracellular fluid, blood plasma, or interstitial fluid, which reflects its role in cellular function and homeostasis.

While potassium is also present in the extracellular fluid and blood plasma, these levels are regulated carefully through mechanisms such as renal function and hormonal control, particularly by aldosterone. Nonetheless, the majority of the body's potassium resides within the cells, emphasizing the importance of intracellular fluid as the primary reservoir for this essential ion.