Total body water (TBW)

Total body water (TBW) represents the total volume of water contained within the human body, typically accounting for approximately 60% of total body weight in lean adult males and 50% in lean adult females (StatPearls, 2023). It is distributed across two primary compartments: the intracellular fluid (ICF), which contains about two-thirds of TBW, and the extracellular fluid (ECF), which contains the remaining third (NIH, 2022). TBW is critical for maintaining physiological homeostasis, serving as a solvent for biochemical reactions, a medium for nutrient and waste transport, and a key component in thermoregulation (PubMed, 2021). While TBW is a physiological parameter rather than a specific molecular target, it is the primary endpoint for various pharmacological therapies, including diuretics like Furosemide and vasopressin receptor antagonists like Tolvaptan (FDA, 2020). Pathological alterations in TBW, such as volume overload in heart failure or depletion in severe dehydration, are major clinical concerns that require precise management of fluid and electrolyte balance (Mayo Clinic, 2023). Consequently, drugs targeting renal transporters and water channels (aquaporins) are used to modulate the size and composition of the body water pool to treat diverse conditions ranging from edema to hyponatremia.

Other names

Body water poolTotal body water volumeBody water compartment

Modulation of renal water and electrolyte excretion via interaction with specific transporters (e.g., NKCC2, NCC) and receptors (e.g., V2 vasopressin receptor).