From the Guidelines
Magnesium oxide (MgO) is the most recommended magnesium supplement due to its efficacy, tolerability, and low cost, as supported by recent clinical trials 1. When considering magnesium supplements, it's essential to prioritize forms that have been evaluated in clinical trials. MgO has been studied in several randomized controlled trials (RCTs) and has shown to be effective in managing constipation-related symptoms. The typical dose of MgO used in trials is 1.5 g/d, but lower doses of 500 mg/d to 1 g/d are often used in clinical practice. Some key points to consider when choosing a magnesium supplement include:
- Bioavailability: MgO has been shown to be effective in clinical trials, but its bioavailability may vary compared to other forms like magnesium glycinate or citrate.
- Digestive side effects: MgO may cause fewer digestive side effects compared to other forms, but individual tolerance can vary.
- Cost and availability: MgO is generally inexpensive and widely available over-the-counter.
- Renal impairment: Magnesium supplements should be avoided in individuals with significant renal impairment (creatinine clearance <20 mg/dL) due to the risk of hypermagnesemia 1. Other forms of magnesium, such as magnesium glycinate, malate, or taurate, may have potential benefits, but their efficacy and bioavailability are less well-studied compared to MgO. It's crucial to consult with a healthcare provider before starting any magnesium supplement, especially if you have kidney disease or take other medications regularly, as they may interact with certain medications, including antibiotics and blood pressure drugs.
From the FDA Drug Label
Active ingredient (in each 5 mL) Magnesium hydroxide 400 mg Other information each teaspoonful (5 mL) contains:magnesium 400 mg Each 30 mL contains: Magnesium Hydroxide 2400 mg
The best magnesium supplement cannot be determined as the FDA drug labels provided do not compare the efficacy or safety of different magnesium supplements. The labels only provide information on the active ingredient and dosage of specific products, such as Magnesium hydroxide 400 mg in 5 mL 2 and Magnesium Hydroxide 2400 mg in 30 mL 2.
From the Research
Magnesium Supplement Options
- Magnesium citrate: Studies have shown that magnesium citrate has high bioavailability and can increase muscle and brain magnesium levels in a dose-independent manner 3, 4.
- Magnesium acetyl taurate: This compound has been found to increase brain magnesium levels in all administered subjects 3.
- Microencapsulated magnesium (MAGSHAPETM microcapsules): A clinical study found that this form of magnesium has high bioavailability and reduces adverse side effects compared to other magnesium sources 5.
- Magnesium oxide: While commonly used, magnesium oxide has been shown to have lower bioavailability compared to other forms of magnesium 6, 4.
- Magnesium bisglycinate: No significant increase in magnesium levels was observed after intake of this compound 5.
Factors to Consider
- Bioavailability: The ability of the body to absorb and utilize the magnesium supplement.
- Side effects: Some forms of magnesium may cause gastrointestinal side effects, while others may be better tolerated.
- Dose: The amount of magnesium needed to achieve desired effects may vary depending on the individual and the form of magnesium used.
- Individual needs: Certain populations, such as those with renal stone disease or hypomagnesuria, may require specific forms or doses of magnesium supplements 6, 7.