From the Guidelines
Magnesium oxide (MgO) is the most recommended formulation for oral magnesium supplementation, based on its efficacy, tolerability, and low cost, as supported by recent clinical practice guidelines 1. When considering oral magnesium supplementation, several factors come into play, including the type of magnesium formulation, dosage, and potential side effects.
- The most commonly used magnesium formulations include magnesium oxide, magnesium citrate, magnesium glycinate, and magnesium malate.
- However, MgO has been evaluated in randomized controlled trials (RCTs) and has shown to be effective in increasing the number of complete spontaneous bowel movements (CSBMs) per week and improving quality-of-life scores 1.
- Although other formulations like magnesium citrate, glycinate, lactate, and malate are available, their bioavailability and clinical efficacy for chronic idiopathic constipation are unknown, making MgO a more reliable choice 1.
- A typical recommended dose of MgO is 1.5 g/d, but lower doses of 500 mg/d to 1 g/d are often used in clinical practice 1.
- It is essential to note that magnesium supplements should be avoided in individuals with significant renal impairment (creatinine clearance <20 mg/dL) due to the risk of hypermagnesemia 1.
- In terms of side effects, MgO has been shown to have a low risk of diarrhea, and its use may lead to better stool consistency and quality-of-life scores 1.
From the FDA Drug Label
ACTIVE INGREDIENT Magnesium Glycinate: ~93.75% The FDA drug label does not answer the question.
From the Research
Magnesium Formulations for Oral Supplementation
- The bioavailability of different magnesium formulations varies, with organic formulations appearing to be more bioavailable than inorganic ones 2
- The percentage of absorption is dose-dependent, and all magnesium dietary supplements can maintain physiological levels in healthy people without prior deficit 2
- However, the effectiveness of magnesium supplementation may vary depending on the individual's health status, such as older adults or those with illnesses or previous subphysiological levels 2
Comparison of Magnesium Formulations
- A systematic review comparing different forms of magnesium found that organic formulations have advantages over inorganic ones in terms of bioavailability 2
- The review analyzed 14 studies and found that inorganic formulations are less bioavailable than organic ones 2
- Another study found that oral magnesium supplementation can improve sleep quality in older adults with insomnia, but the quality of evidence is limited 3
Considerations for Magnesium Supplementation
- The quality of literature on oral magnesium supplementation is substandard, making it difficult for physicians to make well-informed recommendations 3
- However, given the low cost and wide availability of oral magnesium supplements, they may be considered for insomnia symptoms or migraine prevention 3, 4
- Increasing dietary magnesium intake may be a more advantageous alternative to supplementation, especially for patients willing to make lifestyle changes 4