The most effective way to increase your magnesium levels is through food, with supplements as a backup when diet alone falls short. Most adults need between 310 and 420 mg of magnesium per day, depending on age and sex. Men generally need 400 to 420 mg, while women need 310 to 320 mg (350 to 360 mg during pregnancy). Getting there is straightforward once you know which foods pack the most magnesium and which habits might be quietly draining it.
Best Food Sources of Magnesium
Seeds and nuts are the most concentrated sources. A single ounce of roasted pumpkin seeds delivers 156 mg of magnesium, nearly half the daily requirement for most women. An ounce of chia seeds provides 111 mg. After that, almonds (80 mg per ounce), cashews (74 mg per ounce), and peanuts (63 mg per quarter cup) round out the top tier.
Leafy greens and legumes are the next best category. A half cup of boiled spinach has 78 mg, and a half cup of cooked black beans has 60 mg. Edamame, shredded wheat cereal, and soy milk each contribute around 50 to 61 mg per serving. Building a day around a handful of pumpkin seeds at breakfast, a spinach salad at lunch, and black beans at dinner gets you well past 300 mg from food alone, before counting smaller contributions from whole grains, bananas, and other everyday foods.
What Blocks Magnesium Absorption
Eating magnesium-rich foods doesn’t guarantee your body absorbs all of it. Two naturally occurring compounds, phytate and oxalate, can bind to magnesium in your gut and prevent uptake. Phytate is concentrated in bran and whole grain cereals. Oxalate is high in spinach, cabbage, broccoli, and Brussels sprouts. This creates an ironic situation: spinach is one of the richest magnesium foods, but its oxalate content reduces how much you actually absorb.
That doesn’t mean you should avoid these foods. It means variety matters. Rotating your magnesium sources between seeds, nuts, legumes, and greens gives you the best overall absorption. Certain types of fiber, particularly wheat bran and cellulose, also reduce magnesium uptake. And taking high doses of calcium, zinc, or iron supplements at the same time as magnesium-rich meals can compete for absorption in the intestine.
Choosing the Right Supplement
If food alone isn’t enough, supplements can fill the gap. But the form of magnesium you choose matters significantly. Magnesium supplements fall into two broad categories: organic salts (like citrate, glycinate, and malate) and inorganic salts (like oxide). The difference comes down to a tradeoff between how much elemental magnesium is in each pill and how well your body can absorb it.
Magnesium oxide contains the most magnesium per pill but has poor bioavailability because it doesn’t dissolve well. Organic forms like magnesium citrate dissolve much more readily and are consistently absorbed at higher rates. Research on supplement bioavailability confirms that solubility matters more than the raw amount of magnesium in a dose. In practical terms, a lower-dose citrate or glycinate supplement may raise your levels more effectively than a higher-dose oxide tablet.
Magnesium glycinate is often preferred by people who experience digestive sensitivity, since citrate can have a mild laxative effect at higher doses. The tolerable upper limit for supplemental magnesium (not from food) is 350 mg per day for adults. Going above that threshold commonly causes diarrhea, nausea, and cramping. Magnesium from food does not carry this risk, so the limit applies only to supplements and fortified products.
Medications That Drain Magnesium
Several common prescription drugs increase how much magnesium your kidneys excrete, making deficiency more likely even if your diet is solid. The biggest culprits include proton pump inhibitors (PPIs) like omeprazole and pantoprazole, which are widely prescribed for acid reflux. PPIs interfere with magnesium absorption in the gut by disrupting both passive and active uptake pathways. Long-term PPI use is one of the most common drug-related causes of low magnesium.
Diuretics are another major category. Both thiazide diuretics (used for blood pressure) and loop diuretics (used for fluid retention) increase magnesium loss through the kidneys. Other medications linked to magnesium depletion include insulin and other diabetes drugs, certain antibiotics, the heart medication digoxin, and immunosuppressants like cyclosporine and tacrolimus. If you take any of these medications regularly, your magnesium needs may be higher than standard recommendations suggest.
Magnesium and Vitamin D Work Together
Magnesium plays a direct role in activating vitamin D. Every enzyme involved in converting vitamin D to its usable form, both in the liver and kidneys, requires magnesium as a cofactor. This means that if your magnesium is low, supplementing with vitamin D alone may not be fully effective. The two nutrients function as a pair: magnesium activates vitamin D, and vitamin D helps regulate calcium and phosphate for bone health. Raising your magnesium intake can improve how well your body uses the vitamin D you’re already getting.
Do Magnesium Creams and Baths Work?
Magnesium sprays, lotions, and Epsom salt baths are heavily marketed, but the evidence behind transdermal magnesium absorption is weak. A 2017 review in the journal Nutrients evaluated the available clinical data and concluded that transdermal magnesium application is “scientifically unsupported.” The outer layer of your skin is designed to repel water-soluble ions, and magnesium in its dissolved form cannot easily penetrate this barrier. Hair follicles and sweat glands make up only 0.1% to 1% of total skin surface, leaving very little area for potential absorption.
In a randomized, placebo-controlled trial, repeated application of a magnesium-rich lotion to 34 healthy volunteers produced no significant difference in blood magnesium levels compared to a placebo. The widely cited study on Epsom salt baths was never published in a peer-reviewed journal. It appeared only on the website of an industry trade group. If you enjoy Epsom salt baths for relaxation, there’s no harm in them, but they are not a reliable way to correct a magnesium shortfall.
Signs Your Magnesium May Be Low
Mild magnesium deficiency often produces no obvious symptoms, which is part of why it goes undetected. Early signs, when they appear, include nausea, loss of appetite, fatigue, and general weakness. As levels drop further, neuromuscular symptoms tend to emerge first: muscle cramps, tremors, and twitching. More severe deficiency can cause numbness, tingling, mood changes including depression and apathy, and in rare cases, abnormal heart rhythms.
Symptoms typically don’t appear until blood magnesium falls below about 1.2 mg/dL, well under the normal range of 1.46 to 2.68 mg/dL. But standard blood tests can be misleading because less than 1% of your body’s magnesium circulates in the blood. You can be functionally low while still showing a normal reading on routine lab work. Chronic inadequate intake, combined with any of the medications or absorption issues described above, is a more practical way to gauge your risk than relying on a single blood test.