Mineral supplements. Macrominerals
Brand names – drugs: Magnerot
Brand names – supplements: Natural Vitality Calm, Doctor's Best High Absorption Magnesium, NOW Foods Magnesium CitrateSupplements are not tested in clinical trials and are not registered as medications.
Updated · Methodology
First line
Oral magnesium salts (citrate, lactate, glycinate) are first-line for documented hypomagnesaemia without severe clinical features. When serum magnesium falls below 0.5 mmol/L or patients have arrhythmias or seizures, intravenous magnesium sulphate is used. The underlying cause is identified and addressed in parallel: diuretics, proton pump inhibitors, chronic diarrhoea, alcoholism.
Sources
ICD-10: E83.4 · ICD-11: 5C64.41
First line
Intravenous magnesium sulphate is the standard for seizure prophylaxis and treatment in severe pre-eclampsia and eclampsia. The multicentre Magpie trial (Lancet 2002, more than 10,000 women) showed a 58% reduction in eclampsia risk. 2020 and Russian Ministry of Health guidelines include magnesium sulphate as a required component of severe pre-eclampsia management. Oral forms are not used in this indication.
This indication applies to parenteral magnesium sulphate, not over-the-counter oral magnesium. It is administered intravenously or intramuscularly in hospital.
Sources
ICD-10: O14/O15 · ICD-11: JA24/JA25
Adjunct
Magnesium citrate or oxide 400–600 mg daily is considered for migraine prophylaxis in patients with contraindications to beta-blockers and topiramate and in women planning pregnancy. Cochrane 2022 rated the effect as modest but clinically meaningful: 20–40% reduction in attack frequency versus placebo. 2012 classifies magnesium as level B (probably effective). The effect develops after 4–8 weeks.
Does not replace standard prophylaxis in frequent or severe migraine. Considered for episodic migraine without aura.
Sources
ICD-10: G43.9 · ICD-11: 8A80.Z
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
Not recommended
The 2020 Cochrane review (11 RCTs, 735 participants) did not confirm the effect of magnesium in idiopathic nocturnal leg cramps in non-pregnant adults. In pregnant women, the effect is weak and clinically insignificant. International guidelines (, BMJ Best Practice) do not include magnesium in first-line therapy. Patients with confirmed hypomagnesaemia are a different indication.
In confirmed hypomagnesaemia, use is justified – but this is a different scenario from typical nocturnal cramps.
ICD-10: R25.2 · ICD-11: 7A82
Not recommended
High-quality RCTs are absent. Small studies showed a weak effect on subjective stress in healthy adults, not exceeding placebo under controlled conditions. International psychiatry societies (, mental health) do not include magnesium in anxiety treatment guidelines. Clinically significant anxiety or depression requires specialist consultation.
ICD-10: F41.9 · ICD-11: 6B0Z
Magnesium is a cofactor for more than 300 enzyme systems, including ATP synthesis, transmembrane calcium and potassium transport, and nucleic acid synthesis. It stabilises myocardial and neuronal membrane electrical activity. Reduces acetylcholine release at neuromuscular junctions, explaining the effect in eclampsia. Salts differ in bioavailability: citrate and glycinate are highly bioavailable (35–40%), oxide is low (4–5%), and sulphate has an osmotic laxative effect.
Oral magnesium at physiological doses is safe in pregnancy. Intravenous magnesium sulphate is used in severe pre-eclampsia and in preterm birth for foetal neuroprotection at 24–32 weeks gestation.
Transfers into breast milk in small amounts. Use at physiological doses in breastfeeding does not require cessation of breastfeeding.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
8 pairs found. Sorted from critical to minor.
Mechanism
Magnesium is among the cations the label names outright. Magnesium-containing antacids and heavily buffered tablets fall under the same warning, so the interaction shows up both with the supplement and with the heartburn remedy the patient does not think of as a drug.
Symptoms
Slow or absent clinical response to the antibiotic, with no intolerance signs to point at the cause.
Management
Interval of 1–2 hours before or 4 hours after. Ask directly about antacids and evening magnesium: they rarely come up when the patient is asked what medication they take.
Sources
Mechanism
Here the supplement does not obstruct the drug: the drug drains the patient of magnesium. The label records hypomagnesaemia as an adverse reaction of unknown frequency and warns that the severe form can come with hypocalcaemia and hypokalaemia. It appears after months or years of treatment, by which point nobody links the symptom to the stomach protector.
Symptoms
Cramps and muscle spasms, tremor, palpitations, dizziness, irritability. In severe cases tetany, arrhythmias and seizures. Low serum magnesium usually travels with low potassium and calcium that will not correct until magnesium is replaced.
Management
On long-term proton pump inhibitor therapy, measure serum magnesium before starting and periodically thereafter, especially alongside digoxin or a diuretic. Oral supplementation corrects most mild cases, but severe hypomagnesaemia often resolves only when the inhibitor is withdrawn. Also review whether it is still indicated: many of these courses run on out of inertia.
Sources
Mechanism
NIH ODS includes oral bisphosphonates among the drugs magnesium interacts with, for the same reason as calcium: binding in the stomach and loss of the small absorbed fraction. Magnesium antacids fall under the label's warning together with other oral medicines.
Symptoms
No direct symptoms. It surfaces as a lack of densitometric response.
Management
Respect the same 30-minute window after alendronate. Evening magnesium does not interfere with the morning bisphosphonate dose.
Sources
Mechanism
Magnesium shares the list with calcium and iron in the doxycycline label. Beyond the supplement, the warning covers magnesium antacids, which patients tend to take precisely for the stomach upset the antibiotic causes.
Symptoms
Reduced course efficacy with no warning signs. The loop closes on itself: the antibiotic causes heartburn, the antacid lowers the antibiotic.
Management
Space by 2–3 hours. For doxycycline's stomach upset, taking it with food and plenty of water works better than adding a magnesium or aluminium antacid.
Sources
Mechanism
Magnesium sits in the same label list as calcium and iron: it reduces levothyroxine absorption by binding in the gut. The effect is somewhat smaller than with calcium, but it counts when magnesium is taken daily at the same hour as the hormone, which is what happens when both live on the bedside table.
Symptoms
Mildly raised TSH across successive checks with no obvious cause and an unchanged hormone dose.
Management
Keep the 4-hour gap. Magnesium is usually taken at night for sleep and night cramps, which fits well with morning levothyroxine. No need to stop it: moving the hour is enough.
Sources
Mechanism
There is a widespread idea that calcium and magnesium cancel each other out and that an exact ratio between them is required. The data do not support it: at usual supplement doses the mutual interference is small and does not translate into deficiency. They do share transporters, but also independent paracellular routes.
Symptoms
No clinical picture associated with this combination.
Management
No particular ratio needs respecting, nor the product that advertises one. If both are taken, the practical order is calcium with a meal and magnesium at night, more for digestive tolerance and magnesium's effect on sleep than for the interaction.
Sources
Pair details →Calcium (oral salts: carbonate, citrate, lactate, gluconate) →
Mechanism
Both are divalent cations sharing part of the absorption machinery, but the interference described between them is far weaker than calcium with iron. At usual supplement doses the effect is small and without demonstrated clinical consequence.
Symptoms
No symptoms attributable to this pair.
Management
No need to rearrange the regimen for this combination. If iron is being taken for diagnosed anaemia and maximum yield matters, spacing it a couple of hours from magnesium costs nothing and fits with evening magnesium.
Sources
Pair details →Iron oral (salts: sulfate, bisglycinate, fumarate, gluconate, polymaltose; heme iron polypeptide, lactoferrin) →
Mechanism
Magnesium theoretically antagonises lithium-driven neuronal excitability, but no clinical cases of efficacy loss at standard magnesium doses (up to 400 mg/day) have been described.
Symptoms
The combination usually causes no specific symptoms. Each drug's individual side effects remain.
Management
No dose adjustment needed. On stable lithium dose, monitor levels on the usual schedule. Higher magnesium doses (over 1 g/day) are discussed separately — hypermagnesaemia risk in chronic kidney disease.
Sources
Opens the checker prefilled with this drug. Pick the second one from your regimen.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Magnesium (oral salts: citrate, glycinate, oxide, sulfate) is evaluated for the following indications with varying evidence strength: Hypomagnesaemia (evidence tier A), Pre-eclampsia and eclampsia (evidence tier A), Migraine prophylaxis (evidence tier B). See the full indication matrix with dosing and citations above on this page.
Common side effects of Magnesium (oral salts: citrate, glycinate, oxide, sulfate) (≥ 1 in 100): Loose stool, diarrhoea – especially with oxide and citrate, Nausea, epigastric discomfort, Flatulence. See the Safety section for uncommon and serious reactions.
Oral magnesium at physiological doses is safe in pregnancy. Intravenous magnesium sulphate is used in severe pre-eclampsia and in preterm birth for foetal neuroprotection at 24–32 weeks gestation.
Transfers into breast milk in small amounts. Use at physiological doses in breastfeeding does not require cessation of breastfeeding.
Magnesium (oral salts: citrate, glycinate, oxide, sulfate) is contraindicated in: Severe renal impairment (eGFR below 30 mL/min/1.73 m²) – hypermagnesaemia risk; High-degree atrioventricular block; Myasthenia gravis (relative – when using intravenous magnesium sulphate); Severe dehydration; Hypersensitivity to components. Full list in the Safety section.
a clinically significant effect on anxiety and stress in healthy people is not confirmed. Clinical anxiety or depression requires psychiatric consultation.
the 2020 Cochrane review did not confirm the effect in people without hypomagnesaemia. For nocturnal cramps, the underlying cause is investigated first: magnesium, calcium, or potassium deficiency, drug side effects.
bioavailability varies 5–10 fold. Citrate and glycinate are absorbed 7–8 times better than oxide. When choosing a supplement, consider the salt form and elemental magnesium content, not the total salt mass on the label.
Direct links to regulator labels. Open in a new tab.
Magnesium L-threonate (Magtein), Magnesium sulfate, Manganese, Molybdenum, Potassium citrate, Boron, Calcium + Cholecalciferol, Phosphorus