What does too much magnesium in your body feel like?

The gut stage, which is what too much magnesium feels like for almost everyone who reaches it

What too much magnesium in your body feels like has two stages that feel nothing like each other, and almost everyone who feels too much feels the first. The gut stage: a dose that exceeds what the small intestine absorbs, over the 400mg guidance level or a poorly absorbed salt at any dose, reaches the colon within six to twelve hours as an unabsorbed remainder that draws water osmotically, and it feels like a bad meal, a griping, bloated abdomen, a sudden urgency, loose stools or frank diarrhoea, and often nausea, especially from a fasted dose, the whole episode arriving within hours of the dose and passing within a day of stopping, with the potassium and fluid the diarrhoea takes sometimes adding a cramping calf and a washed-out tiredness the day after. This is the body's own dose limit and it is unpleasant rather than dangerous in working kidneys, the surplus that was absorbed being excreted by the kidneys within a day or two and never reaching the blood in a quantity that changes how the rest of the body feels, so a healthy adult who took a handful of citrate feels a bad curry and nothing more. It is also, for the reader who has met it, the answer to whether their dose is too high: loose stools mean the salt or the dose exceeded absorption, and a lower dose, a split across two meals or a better-absorbed salt, bisglycinate, is the fix, the too-much pages' first rung.

The blood stage, which almost nobody reaches and feels like sedation, the feelings people wrongly blame on excess, and the mirror filed

The blood stage is hypermagnesaemia, and it is reached almost only when excretion has failed, kidney disease or dialysis, or when magnesium arrived in grams at once, Epsom salts by mouth, magnesium hydroxide laxatives or antacids in quantity, and it feels like a sedation spreading through the body rather than an agitation: a warmth and flushing in the face and skin as blood vessels relax, a heaviness and weakness in the limbs as the neuromuscular junction is damped and the reflexes go, a floating drowsiness and lethargy, dizziness or faintness on standing as blood pressure falls, a slow pulse that the reader may feel as a thudding calm, nausea, and, as it climbs, confusion, slurred speech and, at the extreme, weakened breathing, the warning card's call-now list and the reason excess magnesium is used intravenously to calm rather than to stimulate. The direction matters, because the feelings people most often blame on too much magnesium are the opposite ones: anxiety, a racing heart, insomnia, restlessness, twitching and cramps are the signs of raised neuromuscular and nervous excitability, which is what too little magnesium produces, the very-low page's mirror, and a reader who feels wired, twitchy and sleepless after starting magnesium has not taken too much, has almost certainly taken a normal dose beside caffeine, stress and a bad week, and would, if anything, feel the reverse from an excess. The mirror filed: too much feels like a bad meal in the gut stage that nearly everyone who reaches it reaches, and like a warm, heavy, slow sedation in the blood stage that almost nobody without failed kidneys does, while anxiety, insomnia and twitching are too little's signs and never excess's, the worked example being a dose that stays below both stages, bisglycinate at 300mg elemental, £19.99 for 90 days at 22p.

The verdict, a bad meal for most, a sedation for the few, and a mirror for the confused

What does too much magnesium in your body feel like: in the gut stage that almost everyone who reaches it reaches, like a bad meal, griping, urgency, loose stools and nausea within hours of a dose that exceeded absorption, passing within a day and answered by a lower dose or a better salt; in the blood stage that almost nobody without failed kidneys or a gram-scale ingestion reaches, like a warm, heavy, slow sedation, flushing, weak limbs, drowsiness, dizziness, a slow pulse and confusion, the call-now list; and never like anxiety, a racing heart, insomnia, twitching or cramps, which are the signs of too little that excess would, if anything, calm. A dose that stays below both stages: 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 are the symptoms of too much magnesium?

In the gut, griping, urgency, loose stools and nausea within hours of a dose that exceeded absorption; in the blood, only in failed kidneys or after grams at once, a warm flushed face, heavy weak limbs, drowsiness, dizziness, a slow pulse and confusion.

Can too much magnesium make you anxious or keep you awake?

No: excess magnesium damps nerves and muscles and feels like a sedation, while anxiety, a racing heart, insomnia, twitching and cramps are the signs of raised excitability that too little magnesium produces, so a wired, sleepless reader has not overdosed.

How quickly do you feel too much magnesium?

The gut stage within six to twelve hours, as the unabsorbed remainder reaches the colon and draws water, passing within a day of stopping; the blood stage develops as magnesium accumulates in someone whose kidneys cannot excrete it or who ingested grams at once.

Can a healthy person feel the serious effects of too much magnesium?

Almost never from capsules: working kidneys excrete the absorbed surplus within a day or two, so a healthy adult's too much stops at the gut stage, and the sedation of hypermagnesaemia needs failed kidneys or a gram-scale ingestion of Epsom salts, laxatives or antacids.

What should I do if magnesium gives me loose stools?

Read it as the body's dose limit: lower the dose, split it across two meals or switch to bisglycinate, the best-absorbed and least laxative salt, and count any hidden magnesium from antacids, laxatives or a multivitamin.

Sources

1. The hypermagnesaemia literature: raised serum magnesium is rare with normal kidney function and occurs with impaired excretion or massive intake from magnesium laxatives and antacids, presenting with nausea, lethargy, low blood pressure, muscle weakness and slowed heart conduction, and treated in hospital with intravenous calcium and, where needed, dialysis. PubMed record
2. The magnesium absorption kinetics literature: oral magnesium is absorbed mainly in the distal small intestine over the hours after a dose, the unabsorbed remainder reaching the colon within six to twelve hours where its osmotic effect appears, and surplus absorbed magnesium is excreted by the kidneys within a day or two. PubMed record
3. 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
4. The magnesium and neuromuscular junction physiology: magnesium antagonises calcium at the presynaptic terminal and reduces acetylcholine release, so magnesium excess depresses neuromuscular transmission and produces weakness, while magnesium deficiency increases neuromuscular excitability and produces twitching, cramps and tetany. PubMed record

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