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It’s not just about how much magnesium you eat
Most conversations about magnesium deficiency focus on dietary intake: are you eating enough? But for a significant number of people, the problem isn’t just insufficient intake. It’s that something is actively draining their magnesium faster than they can replace it.
Several common medications, lifestyle habits, and health conditions either increase magnesium losses through the kidneys, reduce absorption in the gut, or both. Understanding which of these apply to you is often more useful than simply adding more magnesium-rich foods.
For context on the symptoms that can result from low levels, see our guide to signs of magnesium deficiency.
Medications that deplete magnesium
Several widely prescribed drugs have a well-documented effect on magnesium status. This is not a reason to stop taking them without medical advice, but it is a reason to be aware.
| Drug class | Common UK examples | How it depletes magnesium | Depletion risk |
|---|---|---|---|
| Proton pump inhibitors | Omeprazole, lansoprazole, pantoprazole | Impairs gut absorption via TRPM channels | High with long-term use |
| Loop diuretics | Furosemide | Increases urinary excretion directly | High |
| Thiazide diuretics | Bendroflumethiazide | Increases urinary excretion directly | Moderate to high |
| Metformin | Metformin | Impairs intestinal absorption | Moderate |
| Aminoglycoside antibiotics | Gentamicin (hospital use) | Renal magnesium wasting | High, typically short-term |
| Stimulant laxatives | Various | Reduces gut absorption window | Moderate with chronic use |
Proton pump inhibitors (PPIs)
PPIs, including omeprazole (Losec), lansoprazole (Zoton), and pantoprazole, are among the most commonly prescribed drugs in the UK. They are used to manage acid reflux, gastritis, and stomach ulcers.
Long-term PPI use is a well-established cause of hypomagnesaemia. The mechanism involves reduced magnesium absorption in the small intestine: PPIs appear to impair the transient receptor potential melastatin (TRPM) channels that transport magnesium across the gut wall. A review in Kidney International (Danziger et al., 2013) found that patients on long-term PPI therapy had significantly lower serum magnesium levels, and that the effect was dose-dependent.
If you have been on a PPI for more than a year, magnesium monitoring is worth raising with your GP.
Diuretics
Loop diuretics such as furosemide and thiazide diuretics such as bendroflumethiazide increase urinary magnesium excretion directly. They are commonly used for blood pressure, heart failure, and fluid retention.
Because diuretics work by increasing fluid output through the kidneys, magnesium is lost alongside the excess fluid. This is a recognised side effect, and some prescribers will monitor electrolytes including magnesium in patients on long-term diuretic therapy. If yours doesn’t, it is worth asking.
Metformin
Metformin is the most commonly prescribed drug for type 2 diabetes. Research suggests it may impair intestinal magnesium absorption, and several studies have found lower magnesium levels in people taking metformin compared to controls. Given that type 2 diabetes is itself associated with increased urinary magnesium losses (see below), people on metformin face a double depletion risk.
Some antibiotics and antifungals
Aminoglycoside antibiotics (used for serious infections) and amphotericin B (an antifungal) can cause significant magnesium wasting through the kidneys. These are typically hospital-administered rather than community prescriptions, but the depletion can be substantial and may persist after the course ends.
Long-term laxative use
Stimulant laxatives and those that accelerate gut transit time reduce the window for magnesium absorption in the small intestine. Chronic use can contribute to ongoing deficiency, particularly in older adults who rely on them regularly.
Lifestyle factors that drain magnesium
Chronic stress
Stress and magnesium have a bidirectional relationship that creates a damaging cycle. When you are under sustained stress, the adrenal glands release cortisol and adrenaline. These hormones trigger increased urinary magnesium excretion. Lower magnesium then makes the stress response harder to regulate, because magnesium normally acts as a brake on the HPA axis.
A review in Nutrients (Gröber et al., 2015) described magnesium as “nature’s physiological calcium antagonist” and noted that psychological stress consistently elevates urinary magnesium losses. The more prolonged the stress, the more significant the cumulative depletion. For more on this mechanism and what it means in practice, see our post on magnesium glycinate for anxiety.
Alcohol
Alcohol increases urinary magnesium excretion acutely with each drink. It also impairs magnesium absorption in the gut, and heavy or chronic drinking is a well-established cause of magnesium deficiency. Even moderate regular drinking can contribute to suboptimal levels over time.
If you drink regularly and also experience muscle cramps, poor sleep, or the other signs in our magnesium deficiency guide, alcohol intake is worth factoring in alongside diet.
Caffeine and coffee
Caffeine has a mild diuretic effect and can increase urinary magnesium excretion. The effect per cup is modest, but for people drinking several cups daily on an already-low magnesium intake, it adds up over time. Tea has a similar but smaller effect.
This doesn’t mean cutting caffeine is necessary or particularly impactful as a standalone measure. But if you are trying to replenish magnesium levels, heavy caffeine intake is one variable worth keeping in mind.
High sugar intake and refined carbohydrates
Processing and excreting large amounts of glucose requires magnesium. Every time blood sugar spikes and the kidneys filter the excess, magnesium is pulled along with it. A diet high in refined carbohydrates and sugar creates a persistent demand on magnesium that dietary intake may not be able to keep pace with.
This is one of the reasons magnesium deficiency and insulin resistance tend to co-occur: each makes the other worse.
Intense or prolonged exercise
Magnesium is lost through sweat, and during intense exercise the kidneys also increase excretion in response to hormonal changes. Endurance athletes and people who train heavily are at higher risk of depletion than the general population. If you exercise regularly and experience frequent muscle cramps or poor recovery, magnesium is a logical place to start.
Health conditions that increase losses
Type 2 diabetes and insulin resistance
High blood glucose levels directly increase urinary magnesium excretion. The kidneys filter more when glucose is elevated, and magnesium is excreted in proportion. Studies consistently show lower magnesium status in people with type 2 diabetes, and the relationship appears to go both ways: magnesium deficiency impairs insulin receptor function and glucose metabolism, creating a feedback loop.
A meta-analysis in World Journal of Diabetes (Barbagallo & Dominguez, 2015) found that magnesium supplementation improved insulin sensitivity in both diabetic and at-risk individuals, suggesting that correcting deficiency may have metabolic benefits beyond the immediate symptoms.
Coeliac disease and inflammatory bowel disease
Any condition that impairs small intestine absorption will reduce magnesium uptake. Coeliac disease (untreated or poorly managed), Crohn’s disease, and short bowel syndrome are among the most significant. People with these conditions should be monitored for magnesium status as part of routine care, though this doesn’t always happen systematically.
Kidney disease
The kidneys regulate magnesium balance, retaining more when intake or levels are low. In chronic kidney disease this regulatory function is impaired, which can lead to either excessive loss or, in later stages, accumulation. Any significant kidney condition warrants formal monitoring of magnesium alongside other electrolytes.
Why modern diets fall short even with a reasonable diet
Beyond individual depleting factors, there is a broader issue with the magnesium content of food itself. Intensive farming practices over the past 50 to 70 years have reduced the mineral content of UK soils, meaning that vegetables and grains grown today contain measurably less magnesium than the same crops did in mid-20th century analyses.
A widely cited comparison published in the British Food Journal (Mayer, 1997) found that between 1940 and 1991 the magnesium content of UK vegetables declined by an average of 24%, with some crops showing losses of 35% or more. More recent data from the McCance and Widdowson food composition tables supports a similar trend.
This means that even people eating what would previously have been considered a magnesium-sufficient diet may be falling short without realising it.
How to address ongoing depletion
If one or more of the factors above applies to you, increasing dietary magnesium alone is often not enough to keep pace with losses. Supplementation becomes more logical in this context.
The form matters. Magnesium oxide has poor bioavailability and is primarily a laxative at higher doses. Magnesium glycinate (bisglycinate) is well absorbed, gentle on the digestive system, and the form most studied for sleep, mood, and muscle function. It is also the better choice for people with gut conditions who need reliable absorption without irritation. For guidance on dose and timing, see our post on when to take magnesium glycinate.
If you are on long-term PPIs, diuretics, or metformin and haven’t had your magnesium levels checked, it is worth asking your GP for a test. A low-normal result in the context of one of these medications is not something to leave unaddressed.
Our Epsilon Life Magnesium Glycinate is pure, non-buffered magnesium bisglycinate: no oxide blending, no fillers, and independently tested by Campden BRI. Each capsule provides 55mg elemental magnesium. For more on why the buffering question matters, see our post on buffered versus non-buffered magnesium glycinate.
FAQ
Does coffee deplete magnesium?
Caffeine has a mild diuretic effect that can increase urinary magnesium excretion. The impact of one or two cups per day is modest. For people drinking four or more cups daily on an already-low magnesium intake, the cumulative effect is worth factoring in. Switching to decaf or reducing intake is one option, though supplementing is generally more practical.
Does alcohol deplete magnesium?
Yes. Alcohol increases urinary magnesium excretion both acutely and chronically, and also impairs intestinal absorption. Regular alcohol consumption is one of the more significant lifestyle causes of magnesium deficiency. People who drink regularly and experience muscle cramps, poor sleep, or anxiety should consider magnesium supplementation alongside any other lifestyle adjustments.
Can omeprazole cause low magnesium?
Yes. Omeprazole and other proton pump inhibitors are a well-documented cause of hypomagnesaemia, particularly with long-term use. The effect is dose-dependent and can develop within months. The Medicines and Healthcare products Regulatory Agency (MHRA) issued guidance in 2012 advising that serum magnesium should be checked in patients on long-term PPI therapy, though this is not always acted upon in practice.
Does stress deplete magnesium?
Yes. Cortisol and adrenaline released during stress increase urinary magnesium losses. This creates a cycle: stress depletes magnesium, and lower magnesium makes the stress response harder to regulate. Chronic or sustained stress is one of the more significant non-dietary causes of magnesium insufficiency.
What foods deplete magnesium?
No single food directly strips magnesium from the body, but a diet high in refined sugar and processed carbohydrates increases the metabolic demand for magnesium through glucose processing. Phytic acid in unleavened grains can also bind magnesium in the gut and reduce net absorption, though this is less of a concern in a varied diet with adequate overall intake.
Do statins deplete magnesium?
The evidence is limited. Unlike PPIs or diuretics, statins don’t have a well-established mechanism for depleting magnesium. The main nutrient depletion concern associated with long-term statin use is CoQ10, not magnesium. If you are on a statin and concerned about your levels, it is worth checking whether any other depleting factors apply to you before attributing it to the statin.
Do beta blockers deplete magnesium?
Beta blockers are not a primary cause of magnesium depletion. The blood pressure medications most clearly associated with magnesium losses are diuretics, particularly loop and thiazide diuretics, which increase urinary excretion directly. If you are on a beta blocker alone, magnesium depletion is unlikely to be a significant concern. If your prescription includes a diuretic alongside it, the diuretic is the relevant factor.
References
- Danziger J et al. Proton-pump inhibitor use is associated with low serum magnesium concentrations. Kidney International. 2013;83(4):692–699. PubMed
- Gröber U et al. Magnesium in Prevention and Therapy. Nutrients. 2015;7(9):8199–8226. PubMed
- Barbagallo M, Dominguez LJ. Magnesium and type 2 diabetes. World Journal of Diabetes. 2015;6(10):1152–1157. PubMed
- Mayer AM. Historical changes in the mineral content of fruits and vegetables. British Food Journal. 1997;99(6):207–211.
- MHRA Drug Safety Update: Hypomagnesaemia associated with prolonged use of proton pump inhibitors. 2012. MHRA
This article is for informational purposes only and does not constitute medical advice. If you are on long-term medication and concerned about magnesium status, speak to your GP before making changes to your supplementation.
