Dr. Eric Berg DC · 2026-05-05 · Eric Berg (host)
The #1 Magnesium Mistake Everyone Makes
15 research-tied claims examined: 2 contradicted 1 overstated 1 context 7 supported 4 unverified
7 Supported by research
The Recommended Dietary Allowance (RDA) for magnesium was established in 1997 based on reference body weights of 133 pounds for women and 166 pounds for men.
"Now, the RDA for magnesium was set up in 1997 based on body weight, which correlated to women that weigh 133 lb, which nowadays a lot of women weigh more than that, and men that weighed 166 lb, which nowadays they weigh a lot more." (said at 0:02:04)
The 1997 Dietary Reference Intakes (DRIs) established by the Institute of Medicine set Recommended Dietary Allowances (RDAs) for magnesium using standard reference body weights based on historical adult reference averages (approximately 133–134 lb / 61 kg for women and 166–167 lb / 76 kg for men). Published research confirms that these 1997 reference weights were lower than modern average body weights, and recalculating magnesium requirements using updated body weight data yields higher daily recommended intakes for both men and women.
Magnesium oxide has an absorption rate of only 4 percent in the human body.
"But, the problem with magnesium oxide is it only has a 4% absorption rate. That means if you're taking a 400 mg magnesium oxide pill, the body might absorb 16 mg." (said at 0:03:40)
Human bioavailability research supports the claim that magnesium oxide has a fractional absorption rate of approximately 4%. In a clinical comparison of commercial oral magnesium preparations in healthy volunteers, urinary magnesium excretion measurements demonstrated that magnesium oxide had a fractional absorption rate of approximately 4%, which was significantly lower than organic salts and other inorganic forms like magnesium chloride.
Magnesium acts as a cofactor at glutamate receptors to turn down neuronal excitation.
"Glutamate is the on and then GABA is the off switch or the calming effect in the neurons. And so, what you need to know is magnesium is the helper, it's called the cofactor, for this receptor to help wind this system down. To allow the overexcited neurons to turn down. But when magnesium is low, we have no way of turning down this gas pedal." (said at 0:06:12)
Extracellular magnesium is a well-established physiological regulator of neuronal excitability. It acts primarily as a voltage-dependent channel blocker of N-methyl-D-aspartate (NMDA) subtype glutamate receptors. At resting membrane potentials, hydrated magnesium ions lodge within the receptor pore to prevent calcium influx and dampen baseline excitatory signaling, only unblocking upon sufficient membrane depolarization. When extracellular magnesium concentrations drop, this blockade is diminished, resulting in heightened NMDA receptor activation and increased neuronal excitability.
- supports: Ageing, hippocampal synaptic activity and magnesium. (Magnesium research 2006) · cited 73x in the literature
"One of general properties of magnesium at presynaptic fibre terminals is to reduce transmitter release. At the postsynaptic level, it closely controls the activation of the N-methyl-D-aspartate receptor, a subtype of glutamate receptor, which is critical for the expression of long-term changes in synaptic transmission." (abstract, passage verified)
pubmed - supports: Molecular mechanism of calcium permeability and magnesium block in NMDA receptors. (Nature neuroscience 2026) · cited 2x in the literature
"N-methyl-D-aspartate-type glutamate receptors, which bind glutamate and glycine and facilitate Ca 2+ influx upon relief of Mg 2+ channel block during membrane depolarization. However, the structural mechanism underlying Ca 2+ permeability and Mg 2+ blockade in N-methyl-D-aspartate-type glutamate receptors has yet to be fully elucidated. Here we demonstrate using single-particle cryo-electron microscopy that Ca 2+ permeation through the narrow constriction of the cation selectivity filter involves partial dehydration, as evidenced by several Ca 2+ binding sites. In contrast, Mg 2+ binds outside of the selectivity filter through a water network and remains hydrated, thereby acting as a channel blocker." (abstract, passage verified)
pubmedfull study (doi)
Only 1% of total body magnesium is located in blood plasma, while 99% resides outside the blood.
"Only 1% is in your plasma. So if you're deficient in magnesium, your bones will literally dump some of the magnesium into the blood to maintain that 1%. So you cannot accurately figure out how much magnesium you have through your blood. 99% of it is not in the blood." (said at 0:10:55)
Established physiological and biochemical evidence supports the claim. Total body magnesium is distributed predominantly in bone (approximately 50–60%) and soft tissues/intracellular compartments, with less than 1% to 2% located in blood plasma and extracellular fluid. Because plasma magnesium concentration is tightly defended by renal conservation and exchange with bone reserves, normal serum or plasma levels can persist despite significant tissue or intracellular depletion, limiting the diagnostic value of blood testing alone for total body magnesium status.
Red blood cells contain no mitochondria.
"Well, guess what? There is no mitochondria in the red blood cell. So it's not a good test to evaluate how much magnesium you have." (said at 0:11:45)
Mature mammalian erythrocytes (red blood cells) do not contain mitochondria. During the terminal stages of erythropoiesis, erythroblasts enucleate and clear all intracellular organelles, including mitochondria, via programmed autophagy (mitophagy). As a result, mature red blood cells rely entirely on anaerobic glycolysis for ATP generation.
- supports: Cellular dynamics of mammalian red blood cell production in the erythroblastic island nich… (Biophysical reviews 2019) · cited 48x in the literature
"Erythrocytes from birds, reptiles, amphibians and fish possess nuclei, mitochondria and other organelles: erythrocytes from mammals lack all of these intracellular components." (abstract, passage verified)
pubmedfull study (doi) - supports: Erythrocytes as a preferential target of oxidative stress in blood. (Free radical research 2021) · cited 74x in the literature
"Red blood cells (RBC) are specifically differentiated to transport oxygen and carbon dioxide in the blood and they lack most organelles, including mitochondria." (abstract, passage verified)
pubmedfull study (doi) - supports: Modeling Red Blood Cell Metabolism in the Omics Era. (Metabolites 2023) · cited 11x in the literature
"Red blood cells (RBCs) are abundant (more than 80% of the total cells in the human body), yet relatively simple, as they lack nuclei and organelles, including mitochondria." (abstract, passage verified)
pubmedfull study (doi)
In one tissue biopsy study, 50% of people who were magnesium deficient showed normal blood magnesium levels.
"In one study, they found 50% of people that were deficient had normal blood magnesium levels. And this was a test that they actually did a biopsy and they tested the tissues directly because that's another way to figure out if you have enough magnesium, do a biopsy." (said at 0:12:03)
The statement accurately reflects published findings from a muscle biopsy study in clinical patients. In a 1988 study of 32 patients admitted to a pulmonary intensive care unit who underwent quadriceps femoris needle biopsies, 15 patients (47%, or approximately 50%) were found to have tissue magnesium deficiency despite having normal serum magnesium levels. Overall, serum magnesium accounts for less than 1% of total body magnesium stores and is recognized as a poor indicator of intracellular magnesium status. However, the evidence comes from a small, specific clinical cohort (ICU patients with respiratory failure), yielding low certainty for generalizability across healthy populations.
Modern NPK (nitrogen, phosphorus, potassium) fertilizers inhibit magnesium absorption in agricultural crops.
"And also, the problem is it's very difficult to get magnesium from our foods because the modern farming fertilizers with the NPK, nitrogen, phosphorus, and potassium, tend to inhibit magnesium." (said at 0:13:23)
Plant physiology and agricultural research confirm that high potassium (K+) concentrations, such as those supplied by conventional NPK (nitrogen, phosphorus, potassium) fertilization, competitively inhibit magnesium (Mg2+) uptake by crop roots. Potassium and magnesium share non-specific cation uptake pathways, and high K+/Mg2+ ratios in soil or hydroponic media are a well-documented primary driver of induced magnesium deficiency in crops.
Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.