Magnesium and medications.
Magnesium is classified as a foundation supplement in the Distil database, evidence Grade A. The page below lists every medication we have explicitly assessed it against.
Magnesium sits behind more than 300 enzyme reactions, from muscle and nerve function to blood pressure and the body's handling of stress, and most people in the UK fall a little short of the recommended intake. The form on the label changes how well it is absorbed and how it sits with you: glycinate and malate are well absorbed and gentle, citrate is reasonable but mildly laxative, and oxide is cheap but poorly absorbed. Evidence suggests magnesium may support sleep quality, muscle recovery, and blood pressure, though the research is broad rather than deep. Whichever form you take, the drug interactions are the same, because they come from the magnesium itself: separate it by two hours from antibiotics, bisphosphonates, and gabapentin, since magnesium binds them in the gut and reduces their uptake, and long-term proton pump inhibitors or loop diuretics can lower your magnesium over time. It pairs naturally with vitamin D3. Anyone with kidney disease should only take it under GP supervision.
Below are the 13 documented pairs we have explicitly assessed for Magnesium: 13 amber. The pairs cluster around 3 mechanisms: Absorption interference, Mineral chelation (absorption), and Renal magnesium wasting (drug-induced). Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.
Documented interactions
Absorption interference
Long-term esomeprazole use is associated with low blood magnesium in about 1 in 5 chronic users. Supplementing magnesium is generally helpful, but if you have heart, kidney, or muscle symptoms on long-term esomeprazole, ask your GP for a magnesium blood test.
Long-term lansoprazole use is associated with low blood magnesium in about 1 in 5 chronic users. Supplementing magnesium is generally helpful, but if you have heart, kidney, or muscle symptoms on long-term lansoprazole, ask your GP for a magnesium blood test.
Long-term omeprazole use is associated with low blood magnesium in about 1 in 5 chronic users. Supplementing magnesium is generally helpful, but if you have heart, kidney, or muscle symptoms on long-term omeprazole, ask your GP for a magnesium blood test.
Long-term pantoprazole use is associated with low blood magnesium in about 1 in 5 chronic users. Supplementing magnesium is generally helpful, but if you have heart, kidney, or muscle symptoms on long-term pantoprazole, ask your GP for a magnesium blood test.
Mineral chelation (absorption)
Magnesium binds to alendronic acid in the gut and blocks absorption in the same way calcium does. Take alendronic acid first thing on an empty stomach with plain water, stay upright for 30 minutes, then wait at least two hours before any magnesium supplement.
Magnesium can bind to ciprofloxacin in the gut and sharply reduce how much antibiotic you absorb, which may let an infection persist. Take ciprofloxacin at least two hours before, or six hours after, any magnesium supplement.
There are two things to know here, and on balance magnesium is more helpful than harmful. Taking magnesium at the same time as digoxin can slightly reduce how much digoxin you absorb, so it is sensible to separate them by about two hours. At the same time, a low magnesium level makes digoxin more likely to cause dangerous heart rhythms, so keeping your magnesium in the normal range is protective. Because digoxin has a narrow safe range, tell whoever prescribes it that you take magnesium.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Magnesium can bind to doxycycline in the gut and reduce how much antibiotic you absorb, which may let an infection persist. Take doxycycline at least two hours before, or six hours after, any magnesium supplement.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Taking magnesium at the same time as gabapentin can lower how much gabapentin your body absorbs, which may make it work less well. Take gabapentin at least two hours apart from any magnesium supplement, and keep the timing consistent day to day.
Magnesium can bind levothyroxine in the gut and reduce how much you absorb, in the same way that calcium and iron do. Take levothyroxine first thing on an empty stomach and any magnesium supplement at least four hours later (or at bedtime).
Magnesium binds to risedronate in the gut and blocks absorption. Take risedronate first thing on an empty stomach with plain water, stay upright for 30 minutes, then wait at least two hours before any magnesium supplement.
Renal magnesium wasting (drug-induced)
Bumetanide makes the kidneys pass out more magnesium in the urine, so people on it long term often run low on magnesium. This works the opposite way to most interactions: the medicine lowers your magnesium rather than the supplement affecting the medicine, so taking magnesium is generally a supportive response rather than a hazard. If you take bumetanide long term, especially for heart failure, it is worth asking your GP for a magnesium blood test and letting them know you supplement, since low magnesium can affect heart rhythm.
Furosemide makes the kidneys pass out more magnesium in the urine, so people on it long term often run low on magnesium. This works the opposite way to most interactions: the medicine lowers your magnesium rather than the supplement affecting the medicine, so taking magnesium is generally a supportive response rather than a hazard. If you take furosemide long term, especially for heart failure, it is worth asking your GP for a magnesium blood test and letting them know you supplement, since low magnesium can affect heart rhythm.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope. Use the checker below to surface any medication, and submit a missing item if you take something we have not catalogued.
How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologyWant this reasoning across everything you take?
This page checks the pairs you enter. A personalised Distil report applies the same graded, cited reasoning to your whole stack: your goals, conditions, medications, diet, and the compounds worth adding or dropping. The interactions check is one section of it. You can read a real one in full before you decide.
See a real sample reportSomething missing?
If a supplement or medication you take isn't in our autocomplete, tell us. We go through what people flag every week and add what's missing.