Several common medications, health conditions, dietary habits, and lifestyle factors can drive magnesium levels down. Some do it by forcing your kidneys to flush magnesium out faster than normal, others by blocking absorption in your gut. In many cases, multiple factors stack on top of each other, making the problem worse than any single cause would on its own.
Medications That Drain Magnesium
Three drug classes are the most common culprits: acid-blocking medications, water pills, and laxatives.
Proton pump inhibitors (PPIs) like omeprazole and pantoprazole, taken long-term for acid reflux, interfere with magnesium absorption in the gut. The depletion typically builds over years of use rather than weeks, which makes it easy to miss. What makes PPIs particularly risky is how often they’re paired with diuretics. One study found that patients taking both a PPI and a diuretic were 54% more likely to develop low magnesium than people on neither drug. Taking a PPI alone carried almost no increased risk, but the combination changed the picture significantly.
Loop diuretics and thiazide diuretics, commonly prescribed for high blood pressure and heart failure, disrupt the way your kidneys reabsorb magnesium. Normally, your kidneys filter magnesium out of the blood and then pull most of it back in. Both types of diuretics interrupt that recapture process at different points along the kidney’s filtering tubes, letting more magnesium escape into your urine.
Stimulant laxatives, when used frequently, speed food through the intestines too quickly for magnesium to be properly absorbed. Certain antibiotics and some chemotherapy drugs also increase urinary magnesium losses.
Digestive Conditions That Block Absorption
Your small intestine is where most magnesium absorption happens, so any condition that damages its lining can create a deficit. Celiac disease is one of the clearest examples. The immune reaction to gluten flattens the tiny finger-like projections (villi) that line the intestine, reducing the surface area available to absorb nutrients. Even after two years of strictly avoiding gluten, about 20% of people with celiac disease still have low magnesium levels. Iron, zinc, and B12 deficiencies persist at even higher rates.
Crohn’s disease, particularly when it affects the ileum (the last section of the small intestine), creates similar absorption problems. Chronic diarrhea from any cause, whether inflammatory bowel disease, infections, or irritable bowel syndrome, speeds transit time and washes out minerals before they can be absorbed. Surgical removal of portions of the small intestine has the same effect by simply reducing the amount of gut tissue available to do the work.
Alcohol’s Direct Effect on the Kidneys
Alcohol increases magnesium loss through the kidneys in a surprisingly direct way. Within hours of drinking, urinary magnesium excretion rises. The leading explanation is that ethanol or its breakdown products interfere with a cation-exchange mechanism in the kidney’s filtering tubes, essentially disrupting the normal trade of minerals that keeps magnesium in the body. Another possibility is that organic acids produced during alcohol metabolism bind to magnesium, forming complexes the kidneys can’t reabsorb.
This isn’t limited to heavy drinkers. Even moderate alcohol intake triggers measurably higher magnesium losses. For people who drink regularly, the effect compounds over time, especially if their diet is already low in magnesium-rich foods.
How Stress Pushes Magnesium Out
When you’re under stress, your body releases adrenaline and cortisol. Both of these hormones cause magnesium to shift out of cells and into the bloodstream. That temporary spike in blood magnesium levels signals your kidneys to excrete more of it. The net result: you lose magnesium through your urine during and after stressful episodes.
This has been measured directly. In one study, adrenaline infusions lowered plasma magnesium in adults. In another, healthy men exposed to sustained noise (used as a stress stimulus) showed increased urinary magnesium and depleted magnesium inside their red blood cells. The relationship runs both directions: magnesium helps regulate the release of cortisol, so as levels drop, the stress response becomes harder to dial back, which drives further magnesium loss. It’s a self-reinforcing cycle.
Dietary Factors That Work Against You
Not getting enough magnesium from food is the most straightforward cause of low levels. The recommended daily intake is roughly 400 to 420 mg for adult men and 310 to 320 mg for adult women. Population surveys consistently show that a large percentage of people in Western countries fall short of these targets.
Part of the problem is the food itself. Long-term agricultural studies have documented a 20 to 30% decrease in magnesium concentrations in fruits and vegetables worldwide over the past several decades. Intensive farming practices, changes in crop varieties bred for yield rather than nutrient density, and soil depletion all contribute. The magnesium content of the same foods your grandparents ate is measurably lower today.
Certain compounds in food also interfere with absorption. Phytic acid, found in whole grains, seeds, legumes, and some nuts, binds to magnesium in the gut and reduces how much your body can take up. This doesn’t mean you should avoid these foods (they’re excellent sources of other nutrients), but it does mean that the magnesium listed on a nutrition label isn’t the same as the amount your body actually absorbs. Cooking, soaking, and fermenting these foods breaks down some of the phytic acid and improves mineral availability.
High intake of calcium or phosphorus from supplements can also compete with magnesium for absorption. Very high-fiber diets, particularly when fiber intake jumps suddenly, may have a similar short-term effect.
Other Medical Conditions
Poorly controlled type 2 diabetes is a significant and underrecognized driver of magnesium loss. High blood sugar increases the volume of urine your body produces, and magnesium gets swept out with it. The more frequently blood sugar runs high, the greater the cumulative loss.
Kidney disease disrupts the organ’s ability to regulate magnesium retention. In early stages, the kidneys may waste magnesium; in advanced stages, the opposite problem (magnesium buildup) can occur. Hyperaldosteronism, a condition where the adrenal glands produce too much aldosterone, also increases urinary magnesium excretion. Hyperthyroidism and parathyroid disorders shift the balance as well.
Prolonged sweating from intense exercise or working in hot environments creates losses through the skin that most people don’t account for. Athletes and outdoor workers in warm climates have measurably higher magnesium requirements.
Why Multiple Factors Stack Up
Low magnesium rarely comes from a single cause. A typical scenario might look like this: someone eats a diet relying heavily on processed foods (low in magnesium to begin with), takes a PPI for reflux and a diuretic for blood pressure, drinks a glass or two of wine most evenings, and deals with chronic work stress. Each factor alone might only nudge levels slightly, but together they can push someone well below the normal serum range of 0.75 to 0.95 mmol/L.
Subclinical deficiency, where levels are technically within range but on the low end, is even more common and harder to detect. Standard blood tests measure only the magnesium circulating in your blood, which represents less than 1% of your body’s total stores. You can be meaningfully depleted at the cellular level while your blood work still looks normal. This is why symptoms like muscle cramps, poor sleep, and fatigue sometimes improve with increased magnesium intake even when lab values appear fine.