Magnesium glycinate is a form of magnesium that contains the amino acid glycine, which makes it highly absorbable by the body. This form of magnesium is mainly used for its calming properties and gentler effect on the digestive system.
While generally safe, magnesium glycinate can cause side effects, especially at higher-than-recommended doses.
High doses of magnesium glycinate can cause diarrhea, which is usually accompanied by nausea and stomach cramps.
Magnesium may cause increased diarrhea because it is poorly absorbed in the intestine, resulting in more frequent bowel movements. However, magnesium glycinate is less likely to cause diarrhea than other forms of magnesium because it’s better absorbed by the body.
Magnesium glycinate may also cause bloating and gas due to some unabsorbed magnesium in the intestine, which attracts more water. However, these side effects are still milder with magnesium glycinate than with other forms of magnesium.
High doses of magnesium glycinate can cause stomach pain or cramps, especially at doses greater than 350 mg daily.
Some people report headaches as a side effect of their magnesium glycinate supplement. Headaches are not a direct side effect of magnesium, but long-term use of extremely high doses of magnesium glycinate can lead to hypermagnesemia (excessive magnesium in the body), which may cause headaches.
That said, magnesium has been found to help with migraines when used in the recommended dose.
Using very high doses of magnesium glycinate supplements for a long time can lead to magnesium toxicity (blood magnesium levels exceeding 1.74–2.61 mmol/L). The risk of magnesium toxicity is higher in people with kidney failure.
Some symptoms of magnesium toxicity include:
- Difficulty breathing
- Facial flushing
- Muscle weakness
- Extreme fatigue
- Low blood pressure
- Urine retention
- Cardiac arrest
- Blurred vision
If you notice any of these side effects, please stop taking magnesium glycinate and consult your healthcare provider immediately.
Do not take magnesium glycinate supplements without first talking to your healthcare provider if you:
- Have impaired kidney function or kidney disease
- Have had or are currently diagnosed with heart disease, such as a heart attack or arrhythmia (irregular heartbeat)
- Have a neuromuscular disorder like myasthenia gravis (a condition that causes muscle weakness)
- Are you taking other medications like biphosphonates (alendronate) or lithium-based drugs used to treat mood disorders like bipolar disorders?
Some ways to minimize the side effects of magnesium glycinate include:
- Take a magnesium supplement with food to help reduce the risks of stomach pain and nausea.
- Drink enough water while taking magnesium glycinate to reduce the risk of bloating.
- If diarrhea develops, reduce the dose as diarrhea is one of the first signs of magnesium overdose.
- Space your magnesium dose. Give it at least 2 to 3 hours before taking another medication to avoid drug interactions.
- Do not take more than the recommended dose to reduce the risks of side effects and toxicity.
- Always consult your healthcare provider before using magnesium, especially if you have underlying conditions like kidney failure and hypothyroidism (too little thyroid hormones) that can increase your risk of hypermagnesemia.
