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Magnesium is involved in over 300 enzymatic reactions in the body — from muscle function to heart rhythm to energy production. And yet around a third of Germans don't absorb enough of it.Particularly problematic: Many of the most commonly prescribed drugs in Germany further reduce magnesium levels. Pantoprazole, torasemide, HCT and even metformin are so-called “magnesium predators.” Anyone who takes three or more of them has a significant risk of a relevant magnesium deficiency — often undetected.
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Magnesium deficiency can be caused by medications. Dose adjustments and laboratory checks only in consultation with a doctor. This article does not replace medical advice.
Magnesium is involved in over 300 enzymatic reactions in the human body – from energy production to control of the heart rhythm. At the same time it is one of the most common nutrient deficiencies in Germany: according to the National Nutrition Survey II, almost a third of Germans do not reach the recommended daily intake. A particular pitfall: the magnesium deficiency is often invisible in the lab.
| Property | Details |
|---|---|
| Active substance | Magnesium (various compounds) |
| ATC code | A12CC |
| Substance class | Mineral / electrolyte |
| DGE recommendation | 300 mg/day (women) / 350 mg/day (men) |
| EFSA upper limit (supplements) | 250 mg/day in addition to the diet |
| Blood measurement | Serum magnesium (normal value: 0.75–1.05 mmol/L) |
| Available forms | Tablets, capsules, granules, effervescent tablets, injection solution |
| Prescription status | No (as a supplement); high-dose as a medicine |
| Special feature | Intracellular store – the serum level shows only 1% of the total! |
Magnesium is not a single active substance for one particular function – it is a universal cofactor. Without enough magnesium, numerous enzymes cannot work that are responsible for muscle contraction, heart rhythm, energy metabolism, and nerve function. That explains why a magnesium deficiency can cause so many different symptoms at the same time.
An often underestimated connection: magnesium is absolutely necessary for the activation of vitamin D. Vitamin D is converted into its active form in the liver and kidney – both steps are magnesium-dependent. Anyone who sees no improvement in their values despite vitamin D supplementation should therefore always also check the magnesium status.
| Function | Effect of a deficiency |
|---|---|
| Muscle contraction & relaxation | Muscle cramps (above all calf cramps), twitching |
| Heart rhythm | Heart rhythm disturbances, extrasystoles, tachycardia |
| Energy metabolism (ATP) | Fatigue, exhaustion, reduced performance |
| Nervous system | Restlessness, irritability, sleep disturbances |
| Bone metabolism | Osteoporosis risk (magnesium needed for vitamin D activation!) |
| Potassium homeostasis | Magnesium deficiency = treatment-resistant potassium deficiency! |
| Blood sugar regulation | Insulin resistance, worsening in diabetes |
The symptoms of a magnesium deficiency are varied – and are therefore frequently not recognised or wrongly attributed. Calf cramps are blamed on age, fatigue on stress, the eyelid twitch on sitting at the computer. Yet those are exactly the classic early signs.
| Stage | Symptoms |
|---|---|
| Early signs | Muscle twitching, eyelid twitch, fatigue, irritability |
| Moderate deficiency | Calf cramps, headaches, sleep disturbances, a fluttering heart |
| Severe deficiency | Heart rhythm disturbances, tetany, confusion, tremor |
This is the pharmacologically most important chapter of this article. Many of the most frequently prescribed medications in Germany lower the magnesium level – through different mechanisms and with different clinical relevance. The treacherous part: patients take the medications, feel the deficiency symptoms, but no one puts the two together.
Pantoprazole, omeprazole, and other proton pump inhibitors disturb the magnesium transporters in the gut (TRPM6 and TRPM7) and raise the stomach pH, which makes magnesium less soluble. The BfArM has issued an official safety notice: from three months of PPI intake a magnesium deficiency is possible, from one year of intake the risk is clearly increased. This information reaches the fewest patients – and the fewest doctors automatically think of magnesium when calf cramps or a fluttering heart occur on pantoprazole.
The most dangerous combination in heart failure therapy: pantoprazole as stomach protection and torasemide or furosemide as a diuretic. PPIs inhibit the absorption of magnesium in the gut, while loop diuretics at the same time increase the excretion via the kidneys. The magnesium level falls from two sides. This combination is extremely widespread among heart failure patients – and the regular magnesium check is carried out far too rarely. The brite interaction check recognises this constellation automatically.
| Medication | Mechanism | Risk |
|---|---|---|
| Pantoprazole / omeprazole (PPIs) | Disturb Mg transporters in the gut, raised pH lowers solubility | Relevant from 3 months, increased from 1 year. BfArM warning! |
| Torasemide / furosemide (loop diuretics) | Increased renal magnesium excretion | High – regular check! |
| HCT / xipamide (thiazides) | Increased renal excretion | Moderate to high |
| Metformin | Inhibits magnesium absorption | Moderate with long-term therapy |
| Prednisolone / cortisone | Increased renal excretion | Moderate |
| Digoxin / digitoxin | Magnesium deficiency enhances glycoside toxicity! | Caution: arrhythmias! |
| Citalopram / escitalopram | Mg deficiency + QT prolongation = arrhythmia risk | Check Mg level! |
| The contraceptive pill | Oestrogen increases Mg excretion | Slightly increased |
Another important point for patients on citalopram or escitalopram: both SSRIs prolong the QT interval. A magnesium deficiency does the same. Anyone who has both at the same time – an SSRI and a magnesium deficiency – has an increased heart rhythm risk that can be reduced by magnesium replacement. Keep a complete medication list and check all combinations regularly.
On the shelf there are magnesium products with very different names: citrate, glycinate, oxide, malate, taurate. The difference is pharmacologically relevant – not just marketing language. The compound determines how much elemental magnesium is contained per tablet and – even more importantly – how much of it the body can actually absorb.
Magnesium oxide, at 60%, contains the highest proportion of elemental magnesium per gram of substance – which is why it is so widespread in cheap mass products. The problem: the bioavailability is only about 4%. That means that of 500 mg of magnesium oxide on the pack, about 20 mg actually reaches the body. By comparison: magnesium citrate, with a 16% content but considerably better bioavailability, delivers many times the usable magnesium for the same number of tablets. Magnesium oxide is also strongly laxative, because the poorly absorbed magnesium binds water in the gut.
| Compound | Elemental Mg (%) | Bioavailability | Special feature |
|---|---|---|---|
| Magnesium citrate | 16% | High | Well tolerated, good studies. Can be mildly laxative. Best choice on PPIs. |
| Magnesium glycinate (bisglycinate) | 14% | High | Very well tolerated, barely any GI side effects. Best choice with a sensitive stomach. |
| Magnesium oxide | 60% | Low (~4%) | Much Mg per tablet, but poor absorption. Strongly laxative. Not recommended! |
| Magnesium malate | 15% | High | Popular for fatigue and fibromyalgia. |
| Magnesium taurate | 9% | Moderate–high | Recommended for heart patients (taurine has a heart-protective effect). |
| Magnesium carbonate | 24% | Moderate | Neutralises stomach acid. Less effective in PPI patients! |
| Magnesium aspartate | 7% | High | Good absorption, lower Mg density. |
The most important intake rule: spread magnesium over the day in several small doses, not as a single high dose. The reason is physiological: the gut can absorb only limited amounts of magnesium per intake. Excess magnesium stays in the gut and acts osmotically – the result is diarrhoea. Single doses above 250 mg of elemental magnesium should therefore be avoided.
| Group | Recommended dose | Note |
|---|---|---|
| Healthy adults (DGE) | 300–350 mg/day (diet!) | A third of Germans do not reach this |
| Supplementation | Up to 250 mg/day (via supplements) | EFSA recommendation, spread over 2–3 doses |
| On long-term PPI therapy | 200–400 mg/day | Prefer Mg citrate! |
| On diuretics | Individual – according to serum level | Regular check necessary |
| Pregnancy | 310–350 mg/day (total) | Increased need |
| Sport / endurance exertion | Up to 400 mg/day | Compensate for losses through sweating |
Evening intake has an additional advantage: magnesium has a muscle-relaxing effect and can improve falling asleep and sleep quality. Anyone who suffers from calf cramps at night or from sleep disturbances often benefits from taking it shortly before sleep. Record your intake schedule and all medications in your digital medication plan.
