Why Do Magnesium Supplements Make Me Feel Weird?

January 7, 2026 •

4 min read

According to the National Institutes of Health, about 50% of adults in the U.S. don't consume enough magnesium through their diet alone. While supplementation can be beneficial, if you're asking, "Why do magnesium supplements make me feel weird?", you're not alone. Many people experience unexpected side effects, from stomach issues to anxiety, that can be traced to various factors like the type of magnesium, dosage, and your body's unique reaction.

Quick Summary

This article explores the common reasons why magnesium supplements can cause unpleasant side effects, including digestive upset, fatigue, and other neurological symptoms. It covers key factors like the type of magnesium, improper dosage, and potential drug interactions. The guide also provides practical tips for finding the right supplement and reducing weird reactions.

Key Points

Check the magnesium form: Inexpensive forms like oxide and citrate have lower bioavailability and can cause digestive issues. Switching to a better-absorbed type like glycinate or malate can help.
Assess your dosage: Too much magnesium at once can trigger digestive discomfort, fatigue, and other side effects. Start with a low dose and increase gradually as tolerated.
Mind your timing: Taking magnesium supplements with food can improve absorption and reduce the chances of an upset stomach. Splitting the dose throughout the day may also help.
Consider the 'calming' effect: Some people, especially those sensitive to supplements, may misinterpret magnesium's relaxing effect on the nervous system as fatigue, lethargy, or even anxiety.
Watch for interactions: Magnesium can interfere with certain medications like antibiotics and heart drugs. Always consult a doctor to check for potential drug interactions.
Don't ignore severe symptoms: While mild side effects are common, serious symptoms like low blood pressure or severe flushing could indicate magnesium toxicity and require immediate medical attention.
Consult a professional: Before making changes, speak with a healthcare provider to ensure magnesium is appropriate for you and to rule out any other medical conditions.

Understanding the Common Causes of Weird Reactions

Experiencing a strange or uncomfortable feeling after taking a magnesium supplement can be unsettling. The good news is that these reactions are often manageable and rarely a sign of serious danger. Understanding the root cause is the first step toward finding a solution.

Form of Magnesium Matters

Not all magnesium supplements are created equal. The weird feeling you experience can often be linked directly to the chemical form of magnesium you are taking. Some forms are known for their laxative effects, while others have better bioavailability and are gentler on the digestive system.

Magnesium Oxide and Chloride: These inorganic forms are less absorbed by the body. The unabsorbed mineral can pull water into the intestines, causing osmotic diarrhea, which can feel strange and uncomfortable.
Magnesium Citrate: While relatively well-absorbed, it is also known for its strong laxative properties. The effect on gastric motility can lead to sudden, urgent bowel movements and abdominal discomfort.
Magnesium Glycinate: This form is chelated with glycine, an amino acid with calming effects, and is highly bioavailable. It is generally easier on the stomach and less likely to cause digestive distress.
Magnesium L-Threonate: This form is known for its ability to cross the blood-brain barrier, making it more effective for cognitive function and stress reduction, with minimal gastrointestinal side effects.

Dosage Sensitivity and Toxicity

Taking too high a dose of magnesium is a common reason for feeling weird. The recommended daily allowance varies, and many supplements exceed the body's capacity to absorb the mineral at one time.

Digestive Overload: Doses over 350 mg can increase the risk of digestive issues like diarrhea, nausea, and cramping as the body attempts to flush out the excess magnesium.
Magnesium Toxicity (Hypermagnesemia): Though rare in healthy individuals, extremely high intake (over 5,000 mg) can lead to serious toxicity. Symptoms include low blood pressure, muscle weakness, facial flushing, lethargy, and in severe cases, irregular heartbeat or cardiac arrest. This is particularly a risk for individuals with impaired kidney function, as the kidneys are responsible for excreting excess magnesium.

The Magnesium-Anxiety Connection

While magnesium is often praised for its calming properties, some people report feeling anxious or experiencing heart palpitations after taking it. This paradoxical effect can be tied to several factors.

Initial Shock to the System: For some sensitive individuals, the sudden introduction of a high dose of magnesium can briefly disrupt the body's mineral balance, causing a feeling of unease or racing heart.
Interaction with Adrenaline: Magnesium helps regulate the stress hormone cortisol, but an initial change in mineral levels could theoretically trigger a temporary adrenaline response in very sensitive individuals.
Underlying Deficiencies: The body works to maintain a delicate balance of electrolytes, including sodium, potassium, and magnesium. A pre-existing deficiency in other minerals could be exacerbated by a new influx of magnesium, causing an electrical imbalance that leads to heart palpitations.

Comparison of Common Magnesium Supplements

To help you identify which form might be causing your adverse reaction, here's a comparison of several common magnesium supplements.


Feature	Magnesium Glycinate	Magnesium Citrate	Magnesium Oxide	Magnesium L-Threonate
Primary Use	Calming, sleep, gentle digestion	Constipation relief, general supplement	Cost-effective, treating heartburn, constipation	Cognitive enhancement, stress reduction
Bioavailability	Very high	Good	Low	High, crosses blood-brain barrier
Gastrointestinal Impact	Minimal; gentle on the stomach	Strong laxative effect	High risk of diarrhea and upset	Minimal
Best for Sensitive Stomachs	Yes	No	No	Yes

How to Manage Weird Side Effects

If you're experiencing strange feelings, here are some actionable steps you can take.

Adjust Your Dosage and Timing

Start Low, Go Slow: Begin with a minimal dose and gradually increase it over several weeks. This allows your body to adjust and helps you gauge your personal tolerance.
Divide Your Dose: Instead of taking one large dose, split it throughout the day. This can improve absorption and reduce the likelihood of a sudden reaction.
Take with Food: Consuming magnesium with a meal can slow absorption and prevent stomach upset.

Choose a Different Form

As shown in the comparison table, certain forms are more likely to cause side effects than others. If you're sensitive to magnesium, switching from an oxide or citrate to a glycinate or malate could make a significant difference. Pay attention to how your body responds and adjust accordingly.

Consult a Healthcare Professional

Before making any drastic changes, or if your symptoms are severe, always speak with a doctor. They can help determine if your reaction is due to the supplement or an underlying condition. A healthcare provider can also guide you on potential interactions with other medications, as magnesium can affect the absorption of certain antibiotics and blood pressure drugs.

Conclusion: Navigating Your Magnesium Experience

Experiencing a weird or unsettling sensation from a magnesium supplement is a common issue that can be successfully managed. The key lies in understanding the complex interplay between the form of magnesium, the dosage, and your body's unique biochemistry. By starting with a low dose, considering a different, more absorbable form like glycinate or L-threonate, and taking it with food, you can often mitigate undesirable side effects. Always prioritize a discussion with a healthcare professional to rule out any underlying health concerns or medication interactions. This personalized approach will help you harness the many benefits of magnesium without the strange and unwanted side effects, ultimately leading to a more positive and effective supplementation experience.

Disclaimer: The information in this article is for informational purposes only and does not constitute medical advice. Always consult a healthcare professional before starting any new supplement.

Frequently Asked Questions

The most common reason is the type of magnesium and the dosage. Highly absorbable forms or high doses can overwhelm the digestive system, causing diarrhea and nausea, which can feel unusual or unpleasant.

Magnesium glycinate is a great option for sensitive stomachs as it is highly bioavailable and less likely to cause digestive upset. Magnesium L-threonate is another well-tolerated form, especially for cognitive benefits.

Yes, though less common, sensitive individuals may experience anxiety or heart palpitations. This can be due to a sudden shift in mineral balance or an underlying electrolyte issue, which should be discussed with a doctor.

To reduce digestive side effects, you can switch to a gentler form like magnesium glycinate, start with a lower dose, and always take your supplement with food.

Symptoms of magnesium toxicity include low blood pressure, muscle weakness, lethargy, and facial flushing. These typically occur with very high doses and require medical attention.

The best time depends on your goals. For a calming effect or to aid sleep, many people take it in the evening. Taking it with food at any time can improve absorption and reduce side effects.

Magnesium can interact with some medications, including antibiotics, diuretics, and heart drugs. It's crucial to consult your healthcare provider to ensure safe use and proper timing.