However, many individuals commonly associate magnesium with relaxation. “It really relaxes everything in our body,” remarks Deepali Kashyap MD, IFMCP, NMCP, a certified functional medicine physician affiliated with Galleria Women’s Health. “If you experience leg cramps, it helps with that. If you have stomach cramps, it assists with that. It relaxes our blood vessels, which helps to lower blood pressure.”
The ideal way to obtain magnesium is through foods rich in the mineral. Yet, at times, a supplement can provide an additional boost. There are several varieties of magnesium supplements available, with magnesium oxide being one of the most commonly found and cost-effective options.
Magnesium oxide is a compound made of magnesium and oxygen, as noted by the National Library of Medicine (NLM). Although it’s a prevalent form of magnesium found in over-the-counter (OTC) supplements, it is often not recommended by healthcare providers when used in isolation.
In summary: Magnesium oxide may not be the most effective choice for addressing deficiencies, but it does offer some health benefits. Discover these benefits here, along with recommended daily intake and the most suitable magnesium forms for specific health concerns.
How does magnesium oxide differ from other magnesium supplements?
Magnesium oxide is available as an OTC supplement, typically in tablet or capsule formats. It is often consumed to alleviate heartburn, upset stomach, and constipation, according to the NLM.
One key distinction between magnesium oxide and other magnesium supplements—such as magnesium citrate and glycinate—is that magnesium oxide has lower bioavailability. This indicates that a smaller portion of the magnesium in this supplement can be utilized by your body, explains Brynna Connor, MD, a family medicine physician and health-care ambassador at NorthWestPharmacy.com.
A July 2019 study published in Nutrients evaluated the bioavailability of 15 magnesium forms and discovered that magnesium oxide had the lowest solubility and, consequently, bioavailability, despite having a high total amount of magnesium. This implies that for individuals with a magnesium deficiency, this might not be the best form to take. (More information on this below.)
Which supplement is best for magnesium deficiency?
Due to the poor absorption of magnesium oxide into the bloodstream, it is less effective than other magnesium forms that your body more readily utilizes, according to Dr. Connor. If you have a magnesium deficiency, magnesium oxide will likely not be as beneficial compared to other types of magnesium for increasing your blood levels.
The following forms of magnesium are better absorbed than magnesium oxide and more effective for addressing magnesium deficiency:
- Magnesium citrate
- Magnesium glycinate
- Magnesium aspartate
- Magnesium lactate
- Magnesium chloride
If you suspect you have a magnesium deficiency, it’s advisable to schedule an appointment with your physician to have your blood levels assessed. Common signs of low magnesium levels include, according to the U.S. National Library of Medicine:
- Loss of appetite
- Nausea
- Vomiting
- Fatigue and weakness
- Muscle cramps
- Irregular heartbeat
6 potential health advantages of magnesium oxide
While magnesium oxide exhibits the lowest bioavailability among various magnesium types, it still presents several health benefits for specific issues. (If you’re facing any of the following concerns, consult your physician to determine if a magnesium supplement is suitable for you.)
1. It may assist in alleviating headaches
Some studies indicate that a deficiency in magnesium is linked to headaches and migraines.
A February 2021 randomized controlled trial published in Acta Neurologica Belgica found that…
500 milligrams of magnesium oxide has proven effective in preventing migraines, achieving results comparable to the migraine medication valproate sodium. In another randomized controlled trial involving 118 children, daily administration of 9 milligrams per kilogram of oral magnesium oxide markedly decreased the overall number of headache days compared to a placebo group, as noted in a September 2020 review published in Nutrients.
However, magnesium oxide is not the only magnesium variant that is beneficial for migraine prevention. “The most effective form of magnesium for migraines or headaches is magnesium threonate,” states Dr. Kashyap. “We possess a blood-brain barrier that restricts many chemicals in our body from reaching the brain, and magnesium threonate is a form that can cross this barrier, providing substantial relief from headaches,” she adds.
2. It may help bolster your body’s stress response
Magnesium is crucial for the body’s response to stress—it assists in regulating cortisol, the stress hormone, along with specific neurotransmitters in the brain, as per the findings from the Cleveland Clinic.
While additional research is needed, “there is some evidence indicating that magnesium oxide, when taken with vitamin B6, may alleviate anxiety and stress in women, especially those experiencing premenstrual syndrome,” notes Dr. Connor, referencing a May 2017 systematic review in Nutrients.
3. It can aid in alleviating constipation
Numerous studies support the effectiveness and safety of magnesium oxide as a solution for constipation relief. “As an osmotic laxative, magnesium oxide prompts the intestines to release water, which softens the stool and increases the frequency of bowel movements, making them easier to pass,” explains Dr. Connor.
In fact, a January 2021 randomized, placebo-controlled trial published in The American Journal of Gastroenterology revealed that a dosage of 1.5 grams of magnesium oxide was as effective as the well-known laxative senna for alleviating constipation. Additionally, a February 2017 randomized controlled trial in Magnesium Research found that 800 milligrams of magnesium oxide significantly helped prevent constipation following cardiac surgery.
When using magnesium for digestive health and treating constipation, it is typically in the form of a laxative to help normalize bowel movements.
4. It may help lower blood pressure
Magnesium aids in relaxing blood vessels, potentially leading to reduced blood pressure, explains Dr. Kashyap. Although research on this topic is somewhat limited, a small study from 2018 in Nutrients indicated that individuals with hypertension saw significant reductions in blood pressure after taking 300 milligrams of magnesium oxide for one month.
If you are experiencing high blood pressure, it is advisable to consult your doctor to explore prescription medications and lifestyle changes before considering a magnesium supplement.
5. It may aid in stabilizing blood sugar levels
Magnesium contributes to insulin function and the metabolism of carbohydrates—both of which influence blood sugar levels. This implies that supplementing with magnesium might help in stabilizing blood sugar and insulin responses.
A study conducted in May 2020 published in Lipids in Health and Disease found that a combination of 250 milligrams of magnesium oxide and 150 milligrams of zinc sulfate significantly reduced blood glucose levels in individuals with coronary artery disease and type 2 diabetes, in contrast to a placebo. A smaller study from March 2017 published in Medicine demonstrated that addressing low magnesium levels through magnesium oxide supplementation improved blood sugar in children with type 1 diabetes. Furthermore, a small study conducted in January 2019 in Nutrients revealed that a daily intake of 250 milligrams of elemental magnesium, derived from magnesium oxide, gluconate, and lactate, for three months led to significant improvements in both HbA1C and insulin levels. However, further studies are necessary to completely understand the effects of magnesium oxide on blood sugar.
It is essential to remember that if you have elevated blood sugar levels, your first step should be to implement lifestyle modifications, such as managing your sugar intake and exercising, along with following any prescribed medication regimen from your healthcare provider.
6. It may help sustain your skin’s hydration and health
Magnesium can improve blood flow to various organs, including the skin, given its role in widening blood vessels, according to Dr. Kashyap.
“Magnesium is essential for maintaining skin moisture and preventing excessive water loss,” Dr. Connor explains. “Some studies suggest that individuals with significantly dehydrated or damaged skin tend to have lower magnesium levels in their blood.” However, this does not imply that everyone with dry skin has a magnesium deficiency; further investigation is needed to clarify this relationship.
Potential side effects and risks associated with magnesium oxide
Despite being a natural mineral, magnesium supplements can carry risks. It is possible to consume magnesium in excessive amounts. Dr. Connor indicates that symptoms of magnesium overdose (also referred to as magnesium toxicity) may include:
- Cardiac arrhythmias
- Loose stools and diarrhea
- Hypotension
- Facial flushing
- Urinary retention
- Fatigue and depression
- Muscle weakness
- Vomiting and nausea
Individuals who should avoid magnesium oxide
“Those suffering from chronic kidney disease should consult a healthcare professional before starting any magnesium supplementation, as excess magnesium can accumulate in the blood if the kidneys are not working properly,” cautions Dr. Connor.
It is crucial to recognize that certain types of magnesium supplements may have different implications.added sugars or artificial sweeteners, which may not be suitable for individuals managing high blood sugar levels. It’s advisable to thoroughly examine the product label prior to making a purchase or consult your physician for recommended brands.
Potential Drug Interactions
According to Dr. Connor, magnesium oxide may interact adversely with several medications, including:
- Levodopa/carbidopa (Sinemet)
- Some antibiotics
- Bisphosphonates
- Calcium channel blockers
- Muscle relaxants
- Potassium-sparing diuretics
- Anticoagulants and antiplatelet medications
- Sulfonylureas
- Antacids
- Neurontin
- Ketamine
- Sevelamer (Renagel and Renvela)
In general, discussing any new supplements with your healthcare provider is a prudent approach to steer clear of possible negative effects.
Daily Magnesium Oxide Requirements
There isn’t a specific daily intake guideline for particular forms of magnesium, such as magnesium oxide. Generally, adults should target a daily intake of between 310 and 420 milligrams, preferably obtained through food, as stated by the NIH.
If you happen to be low or deficient in magnesium, your physician may suggest taking a magnesium supplement. However, it’s essential to note that magnesium affects individuals differently and may come with distinct benefits, risks, and side effects.
“I typically have patients begin with any form of magnesium at a dosage of 200 milligrams and assess the benefits and side effects,” Dr. Connor explains. “I usually keep them below 500 milligrams of total magnesium daily, but since everyone is unique, it’s crucial to discuss the appropriate dosage with your doctor.”
When to Consult a Doctor
If you’re experiencing symptoms such as fatigue, nausea, weakness, appetite loss, or muscle cramps, and suspect magnesium deficiency, it’s advisable to arrange an appointment with your doctor for blood tests. Should you be found to be deficient, they can recommend specific types of magnesium supplements suitable for restoring your blood magnesium levels (magnesium oxide may not be the preferred option due to its limited bioavailability).
Additionally, if you’re considering magnesium oxide for alleviating headaches or constipation, it’s wise to consult with your healthcare provider to determine if this supplement is appropriate for your needs.
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