Magnesium Distribution
and Triage
Introduction
Magnesium is a major mineral that the body must share between many competing needs, from making ATP to stabilizing nerves, muscles, and DNA. This article first describes how magnesium is stored and moved at the whole‑body level, focusing on the roles of the gut, bone, kidney, and blood. It then explains how cells handle magnesium inside compartments like the cytosol, mitochondria, and nucleus, and why MgATP sits at the center of energy use and enzyme function. Next, it looks at what happens in key tissues including heart, brain, muscle, bone, and the immune system when magnesium intake is low or losses are high, and which functions are protected or sacrificed over time. The article ends by bringing these pieces together into a simple “triage” model that links molecular mechanisms to real‑world symptoms and disease risk.
Distribution and Regulation
Magnesium is distributed and regulated in a way that protects ATP-dependent viability, membrane excitability, and genomic integrity first, while allowing slower-turnover tissues and functions to bear the brunt of insufficiency and deficiency. This “prioritization” emerges from the physical chemistry of MgATP, the kinetics of membrane transporters, compartmental buffering (bone, muscle, cytosol, organelles), and endocrine feedback from gut, bone, and kidney rather than from a single, explicit hierarchy mechanism. [1
Whole‑body distribution and macro‑priorities
In adults, roughly 50–60% of total body magnesium resides in bone (both surface-exchangeable and structural pools), about 20–30% in skeletal muscle, most of the remainder in soft tissues, and only about 1% in extracellular fluid, including serum. Within blood plasma, around two‑thirds of magnesium is ionized (biologically active), with the rest protein-bound or complexed to anions, and this tiny compartment is what clinical labs measure despite being a poor representation of total-body or intracellular status. [1
Whole‑body magnesium homeostasis arises from three main “organs of control”: intestine, bone, and kidney. When intake falls, intestinal fractional absorption increases, renal excretion falls to very low levels, and labile bone surface magnesium is mobilized, effectively sacrificing skeletal and connective-tissue reservoirs to stabilize extracellular and critical intracellular pools. [4
Note from Curious Outlier: I am including this article under Magnesium and the Endocrine system, but it deserves a standalone module for itself. This article does not focus specifically on the endocrine system, but reviews a very important yet understudied and crucial area of magnesium science. I have been studying magnesium science for about a year and a half and I’m just coming to grasp the importance of this topic and I hope that I can make it easier for you to understand.