Is low magnesium dangerous?

Half one, is low magnesium dangerous, graded by severity and traced to its causes

Is low magnesium dangerous is a question with two halves in its search variants, the danger of too little and the downsides of the supplement, and the first half is graded by severity because the word low covers a range from the common and undramatic to the rare and serious. Severe hypomagnesaemia, clinically low serum magnesium, is dangerous: it presents with muscle cramps, tremor and weakness, then with cardiac arrhythmias, and at the extreme with seizures, and it is a medical emergency treated with intravenous magnesium in hospital, but it is rare in otherwise healthy people and has identifiable causes, alcohol misuse above all, the commonest cause in fed adults, long-term proton-pump inhibitors, loop and thiazide diuretics, gastrointestinal loss from chronic diarrhoea, malabsorption or bowel disease, uncontrolled diabetes with its osmotic urinary loss, and some rarer medicines and genetic conditions, so the dangerous version of low magnesium is a consequence of something and not a thing a healthy lifter drifts into. Mild low status, the common version, is undramatic: a magnesium intake below the reference nutrient intake over months produces no emergency, an association with fatigue, cramps, poorer sleep and a duller stress response in the observational literature, and a picture that a diet audit catches before a blood test does, serum magnesium being an imperfect marker of tissue status since the blood is defended at the expense of bone and muscle, a normal serum result not excluding a marginal tissue status and a low one being a real finding. The honest grading: severe deficiency is dangerous, rare and caused; mild low status is common, undramatic and dietary; and a lifter with symptoms and a diet that runs light audits the diet, asks a GP for the blood test if the picture warrants it, and supplements within guidance where the audit says so.

Half two, the supplement's side effects, graded by salt and dose, and the two halves filed

Half two is the downside of the supplement, the variants asking about bisglycinate's side effects, the downside of taking it daily and the 3-in-1's side effects, and it is graded by salt and by dose. The one common side effect of any magnesium supplement is osmotic: unabsorbed magnesium draws water into the bowel, producing loose stools or diarrhoea at surplus doses, and the salts differ, oxide the worst because it is least absorbed, citrate moderate, bisglycinate the least because it is absorbed best, which is why a 3-in-1's side effects are mostly its citrate's and why bisglycinate is the salt this section recommends for a nightly habit, the effect being dose-dependent and the practical ceiling that arrives before any harm in healthy kidneys. The second is nausea from a fasted dose in a minority, fixed by taking it with a meal. The third is accumulation, hypermagnesaemia, and it is the one real danger of the supplement, confined to impaired kidney function, chronic kidney disease, where excretion fails and magnesium builds toward lethargy, low blood pressure and, at extremes, cardiac effects, the without-a-doctor page's red gate, and not a risk in a healthy adult whose kidneys excrete the surplus. The downside of taking magnesium every day is otherwise nothing, the every-night page's finding of no tolerance, dependence or rebound, a maintenance nutrient within the 400mg guidance level being what daily use is for. The two halves filed: severely low magnesium is dangerous, rare and caused by alcohol, medicines or gut disease, mild low status is common and dietary, and the supplement's side effects are loose stools at surplus, least with bisglycinate, nausea fasted and accumulation only in kidney disease, the worked example being the salt with the fewest downsides at a dose under the ceiling, 300mg elemental at 80% NRV, £19.99 for 90 days at 22p.

The verdict, danger at the extremes and gentleness in the middle

Is low magnesium dangerous: severely low magnesium is, with arrhythmias and seizures at the extreme, but it is rare and caused by alcohol, medicines or gut disease rather than drifted into, while mild low status is common, undramatic and dietary, caught by an audit and confirmed by a blood test if the picture warrants, and the supplement's side effects are loose stools at surplus doses, least with bisglycinate, nausea from a fasted dose, and accumulation only in impaired kidneys, with daily use within guidance carrying no tolerance, dependence or rebound. The salt with the fewest downsides at a dose under the ceiling: Futuro Labs Magnesium Glycinate, bisglycinate, 300mg elemental at 80% NRV, £19.99 for 90 days at 22p a day.

What to check on the label

Questions people also ask

What happens if your magnesium is too low?

Mild low status is undramatic, associated with fatigue, cramps and poorer sleep; severe deficiency causes cramps, tremor and weakness and, at the extreme, arrhythmias and seizures, a rare medical emergency with identifiable causes such as alcohol misuse, PPIs, diuretics or gut disease.

What are the side effects of magnesium glycinate?

Loose stools at surplus doses, the osmotic effect all magnesium salts share and bisglycinate carries least, nausea from a fasted dose in a minority, and accumulation only in impaired kidneys, with no tolerance, dependence or rebound from daily use within guidance.

What is the downside of taking magnesium every day?

Nothing for a healthy adult within the 400mg supplemental guidance level, magnesium being a maintenance nutrient that daily use is for, with kidney disease, regular medication and pregnancy the three cases that ask a doctor first.

Can a blood test show low magnesium?

Imperfectly: serum magnesium is defended at the expense of bone and muscle, so a normal result does not exclude marginal tissue status, while a low result is a real finding, which is why a diet audit comes first and a GP test follows where symptoms warrant.

Why does a 3-in-1 magnesium cause more side effects than bisglycinate?

Its citrate and any oxide: the osmotic laxative effect scales with unabsorbed magnesium, and citrate is moderately and oxide poorly absorbed, while bisglycinate is absorbed best and so carries the least.

Sources

1. The hypomagnesaemia literature: clinically low serum magnesium presents with cramps, tremor, weakness and, when severe, arrhythmias and seizures, with alcohol misuse, proton-pump inhibitors, diuretics and gastrointestinal loss the common causes, and serum magnesium an imperfect marker of tissue status. PubMed record
2. The hypermagnesaemia literature: the kidneys excrete surplus magnesium, so supplementation is safe for healthy adults within guidance and warrants medical advice in chronic kidney disease, where impaired excretion allows magnesium to accumulate. PubMed record
3. Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnesium Research 2001;14(4):257-262. PubMed record
4. Expert Group on Vitamins and Minerals. Safe Upper Levels for Vitamins and Minerals. Food Standards Agency, 2003 (magnesium guidance level 400mg a day from supplements). https://cot.food.gov.uk/sites/default/files/vitmin2003.pdf

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