Magnesium Side Effects & Safety: What to Know Before Supplementing
A clear guide to common magnesium supplement side effects, the 350mg adult supplemental upper limit, medicine interactions and when professional advice matters.
Reviewed and updated September 19, 2026 · Alurevia Editorial Team
Magnesium is an essential nutrient, but supplemental magnesium can cause side effects and is not appropriate in every circumstance. The most common issues at higher supplemental intakes are gastrointestinal.
Common magnesium supplement side effects
The NIH Office of Dietary Supplements notes that high doses of magnesium from dietary supplements or medications can cause diarrhea, nausea and abdominal cramping. Some magnesium salts are more likely to have a laxative effect than others.
Why some forms are gentler than others
The laxative effect is largely about how much magnesium stays unabsorbed in the gut, drawing water in with it. Forms that are absorbed less completely tend to have a stronger osmotic effect.
Broadly, and with individual variation:
- More likely to loosen stools: magnesium oxide, magnesium sulfate, magnesium citrate at higher intakes. Magnesium citrate and magnesium sulfate are used in some laxative products, which is a useful clue.
- Often better tolerated: magnesium glycinate, magnesium malate.
This is one reason multi-form products exist. It is a tolerability trade-off rather than a quality ranking, and no form is guaranteed comfortable for everyone. See magnesium oxide vs magnesium glycinate and magnesium glycinate vs citrate for the detail.
What is the adult supplemental upper limit?
The Food and Nutrition Board sets a tolerable upper intake level of 350mg per day from magnesium supplements and medications for adults. The limit does not include magnesium naturally present in food.
For the full picture on recommended versus maximum intakes, see how much magnesium per day.
Who should be especially cautious?
Professional advice is particularly important for people with impaired kidney function, because the kidneys play a central role in magnesium balance. When kidney function is reduced, magnesium is cleared less efficiently and can accumulate.
Caution also applies if you are pregnant or nursing, taking prescription medicines, or already using another magnesium-containing product, including some antacids and laxatives that contain magnesium without advertising it prominently.
Can magnesium interact with medicines?
Yes. The NIH Office of Dietary Supplements documents several categories:
- Bisphosphonates (for bone density): magnesium can reduce their absorption. These are usually separated by at least two hours.
- Tetracycline and quinolone antibiotics (such as doxycycline and ciprofloxacin): magnesium binds them in the gut and reduces absorption of the antibiotic.
- Diuretics: loop and thiazide diuretics can increase magnesium loss, while potassium-sparing diuretics can reduce excretion.
- Proton pump inhibitors: prolonged use has been associated with low blood magnesium.
Timing and individual medication advice should come from a pharmacist or healthcare professional rather than a generic product page. Bring the actual label with you, since the form and the elemental amount both matter.
What to do if a supplement upsets your stomach
Gastrointestinal effects are the most common reason people stop taking magnesium. General, non-medical steps people commonly take:
- Stop and reassess rather than pushing through persistent symptoms.
- Check whether you are taking magnesium from more than one product at once.
- Check the elemental amount on the panel, not the compound weight.
- Take it with food rather than on an empty stomach, if the directions allow.
- Discuss the form and the amount with a healthcare professional before switching products.
Persistent or severe symptoms are a reason to seek professional advice, not to self-adjust a dose.
What about very high magnesium intakes?
Very large amounts of magnesium from supplements or medications can cause serious toxicity. Reported signs of magnesium toxicity include nausea, vomiting, facial flushing, lethargy, muscle weakness and irregular heartbeat, with severe cases being a medical emergency.
This is one reason not to increase a dose beyond the product directions and not to stack multiple magnesium products without professional guidance.
Safety information for Alurevia Magnesium Complex
Alurevia Magnesium Complex provides 500mg elemental magnesium per capsule, which is above the adult supplemental upper limit of 350mg/day. The product page discloses this directly.
Speak with a healthcare professional before use, particularly if you have kidney disease, take prescription medicines, are pregnant or nursing, or use another supplement containing magnesium. Do not exceed the product directions. See the full label and safety information →
Frequently asked questions
Can magnesium cause diarrhea?
Yes. Diarrhea is one of the recognised adverse effects of higher supplemental magnesium intakes.
Can I take magnesium with prescription medicine?
Some medicines can interact with magnesium or have their absorption affected by it. Ask a pharmacist or healthcare professional about your specific medicines.
Is magnesium from food included in the 350mg upper limit?
No. The adult 350mg upper limit applies to supplemental and medication sources, not magnesium naturally present in food.
Which form of magnesium is least likely to upset my stomach?
Glycinate and malate are generally described as better tolerated, while oxide, citrate and sulfate are more associated with a laxative effect. Individual responses vary, and the amount taken matters as much as the form.
Should magnesium be taken with food?
Follow the directions on your specific product. Where the directions permit it, taking a supplement with food is a common approach for people who find it uncomfortable on an empty stomach.
Can you take too much magnesium?
Yes. Very high intakes from supplements or medications can cause toxicity, which in severe cases is a medical emergency. Stay within the product directions and do not combine multiple magnesium products without professional guidance.
Why do some antacids contain magnesium?
Magnesium compounds are used in some antacids and laxatives. This matters because that magnesium counts toward your supplemental total, and it is easy to overlook when adding a separate supplement.
Source
National Institutes of Health, Office of Dietary Supplements: Magnesium Fact Sheet for Health Professionals.
This article is general educational information and is not medical advice. Seek professional guidance for individual medical or medication questions. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
