Do magnesium supplements have any side effects?

Starting a new supplement often brings questions about safety and potential side effects. Magnesium is a vital mineral that supports muscle function, nerve signalling, bone health and energy metabolism. Many people consider taking supplements to ensure they get the benefits of magnesium, but it’s natural to wonder if doing so could cause side effects. Understanding what to expect can help you to make an informed decision and take magnesium safely.

Are magnesium supplements safe?

Magnesium supplements are generally safe for most healthy adults when taken in the recommended doses.¹ The mineral is naturally found in foods like nuts, seeds, leafy green vegetables and whole grains, and supplementation typically mimics the body’s normal absorption process.² For individuals with normal kidney function and no serious underlying health conditions, magnesium supplements rarely cause severe complications.

However, people with kidney disease, certain heart conditions or gastrointestinal issues should consult a healthcare professional before starting supplementation. Excess magnesium can accumulate in the blood if the kidneys cannot excrete it properly, leading to complications such as irregular heartbeat or low blood pressure.³ If you’re pregnant or breastfeeding, you should seek guidance from a healthcare provider to ensure the dose is appropriate for your situation.⁴

For most adults, typical magnesium supplements such as Nutraxin’s Magnesium Complex provide safe and effective support when taken as directed. In addition, understanding your dietary intake and overall nutrient needs – for example, whether you’re already getting enough magnesium from your diet – can help to prevent overconsumption or unnecessary supplementation.⁵

Are there any side effects to taking magnesium supplements?

Like any change to your diet or nutrient intake, taking magnesium supplements carries the potential for side effects. Most of these are mild, temporary and often related to the body adjusting to increased magnesium levels. Side effects are more likely when taking higher-than-recommended doses, or in individuals with certain health conditions.

Gastrointestinal side effects

The most common side effects involve the gastrointestinal tract, a large part of the digestive system. Magnesium acts as an osmotic laxative in higher doses, which means it draws water into the intestines. This can cause diarrhoea, loose stools, nausea or stomach cramps if too much is taken at once.¹ Gradually increasing magnesium intake to the recommended level and taking the supplement with food can help to reduce these effects.

It’ss important to recognise that these symptoms are generally mild and often resolve as the body gets used to your new magnesium intake. Excessive or abrupt doses, however, can lead to more severe gastrointestinal discomfort. Responsible dosing and gradual introduction of magnesium supplements are key to minimising this risk.

Hypermagnesaemia

Hypermagnesaemia, or excessively high magnesium levels in the blood, is very rare in healthy adults but can occur with extremely high doses or in people with impaired kidney function.² Symptoms may include muscle weakness, low blood pressure, irregular heartbeat or, in severe cases, respiratory distress.

Most healthy people would have to take an extremely large dose to experience hypermagnesaemia, which means it’s highly unlikely to happen if you’re taking your supplements as directed – even if you accidentally take a double dose. However, the size of the individual affects what classes as a high dose, and children and pets could easily take an excessive dose by accident. Because of this, it’s important to store magnesium supplements safely, out of reach of children and pets, to prevent accidental overdose.³

Maintaining supplementation within recommended limits and following professional guidance ensures that hypermagnesaemia is highly unlikely. Routine magnesium intake rarely reaches levels that cause serious complications.

Taking magnesium alongside medications

Magnesium supplements can interact with certain medications. For example, they may reduce the absorption of some antibiotics or interfere with medications for blood pressure or osteoporosis.⁴ If you’re taking any prescription medications, it’s essential to consult your doctor or pharmacist before beginning magnesium supplementation.

Healthcare professionals can advise on appropriate timing, dosage and potential interactions to ensure that magnesium supplements support your health without interfering with other treatments. This personalised guidance is particularly important for individuals with complex health conditions or multiple medications.

Final thoughts

Magnesium supplements provide a convenient way to support key bodily functions, especially for individuals who struggle to get enough magnesium through diet alone. Most people tolerate magnesium supplements well when taking recommended amounts, and serious side effects are uncommon. Mild gastrointestinal symptoms may occur during initial use or when taking higher doses, while hypermagnesaemia is very rare and generally limited to people with kidney issues or extremely high intake.³

Anyone considering magnesium supplementation should evaluate their dietary intake, existing health conditions and any medications they take. Pregnant or breastfeeding individuals and people with kidney or heart conditions should seek professional advice to ensure safe use. With informed dosing and responsible use, magnesium supplements can be an effective addition to a balanced diet and contribute to overall health.

References

National Institutes of Health. (2023). Magnesium: Fact Sheet for Consumers. https://ods.od.nih.gov/factsheets/Magnesium-Consumer/
Mayo Clinic. (n.d.). Magnesium: Dosage, Side Effects, and Safety. https://www.mayoclinic.org/drugs-supplements-magnesium/art-20363056
Healthline. (n.d.). Magnesium Supplements: Benefits and Risks. https://www.healthline.com/nutrition/magnesium-supplements
WebMD. (2022). Magnesium and Medication Interactions. https://www.webmd.com/vitamins-supplements/ingredientmono-998-magnesium.aspx
Harvard T.H. Chan School of Public Health. (n.d.). Magnesium in Diet and Supplements. https://www.hsph.harvard.edu/nutritionsource/magnesium/