Difference Between Magnesium Citrate and Magnesium Oxide

The earth contains several elements and they are as much needed in nature as in our bodies. Magnesium is one of those elements which is needed for a healthy body as well as in other different aspects.

Magnesium can be found in various forms and all of them have several usages, magnesium citrate and magnesium oxide are two such forms of magnesium.

Magnesium Citrate vs Magnesium Oxide

The main difference between magnesium citrate and magnesium oxide is that magnesium citrate is a salt of citric acid but magnesium oxide is an inorganic and ionic compound. Magnesium citrate is very bioavailable but magnesium oxide is not bioavailable. Also, magnesium citrate is low in alkaline but magnesium oxide is high in alkaline.

Magnesium Citrate vs Magnesium

Magnesium citrate is a citric acid salt that is low in bioavailability yet has many effective elements for better health. It works as a laxative and doctors recommend this before surgery and other bowel-related treatments. The alkaline in it is low too.

Magnesium oxide gets consumed for many purposes but the most important one is to cure constipation. It also works as a supplement of magnesium and can help treat many diseases such as migraine, heartburn and indigestion.

The bioavailability present in it is high.

Comparison Table Between Magnesium Citrate and Magnesium Oxide

Parameters of ComparisonMagnesium CitrateMagnesium Oxide
Definition It is a magnesium salt of citric acid.It is an inorganic compound.
AlkalineIt is less alkaline.It is highly alkaline.
Molar massIts molar mass is 214.41 g/molIts molar mass is 40.304 g/mol.
UsageIt is used as a laxative.It is mostly used as an antacid.
BioavailabilityIt is not very bioavailable.It has good bioavailability.
FormulaIts formula is C6H6MgO7.Its formula is MgO.
Solubility in waterIt is soluble.It is insoluble.

What is Magnesium Citrate?

Magnesium citrate is an acidic citric salt that gets used to clean the intestines and help it to get rid of all its stool. It gets used before surgeries or bowel procedures like colonoscopy and radiography.

As its objective is to clean the intestines, it also gets utilized to treat constipation.

Magnesium citrate is a saline laxative whose work process includes increasing the amount of fluid in the small intestine. It might take 30 minutes to 3 hours to show effective results.

Sometimes in order to improve the taste of magnesium citrate, it gets chilled in the refrigerator but it should not get frozen under any circumstances.

The dosage of it is based on the patient’s age and medical condition. After taking the product, you need to consume at least 240 millilitres of water. The water will help to avoid the side effects such as dehydration.

But for regular usage, this is not suitable. If you use this frequently then the normal bowel function will get affected.

Over usage of the product will lead to diarrhoea, weakness, decreased weight and many other complications. So for regular usage, stool softener or bulk-forming laxatives should get used.

What is Magnesium Oxide?

Magnesium oxide or magnesia is a hygroscopic solid mineral that is a great source of magnesium. In the medical field, it gets used to treat heartburn and indigestion and works as an antacid.

However, it is also used as a supplement for magnesium. Lack of magnesium in the body can lead to headaches. Balance of magnesium in the body can relieve stress and anxiety and maintain the level of blood pressure.

It is also capable of working as a laxative to treat constipation. However it is not free from side effects, magnesium oxide can cause nausea and cramping as well as bowel obstruction.

In case the lungs get exposed to magnesium oxide powder, the result can be fatal. So using it for a long time or using it in a tremendous amount is not a good idea.

It is not only significant in the medical field but it also gets used as a construction material. It is a primary element in fireproofing. It also has a role to play in the area of food additives.

It can be utilized as an anticaking agent in products as such canned peas and frozen desserts. It works as an insulator in heat-resistant electrical cable.

Main Differences Between Magnesium Citrate and Magnesium Oxide

  1. Magnesium citrate is magnesium salt of citric acid that can work as a supplement of magnesium but magnesium oxide is an iron component.
  2. In chemistry, magnesium citrate is known as C6H6MgO7 and magnesium oxide has MgO as its formula.
  3. Magnesium citrate is less alkaline whereas magnesium oxide is high.
  4. The molar mass of the two is different as well, the molar mass of magnesium citrate is 214.41 g/mol but the molar mass of magnesium oxide is 40.304 g/mol.
  5. Magnesium citrate is used as a laxative but magnesium oxide is used to cure heartburn as an antacid, but it can also get used to treating constipation.
  6. Magnesium citrate is not very bioavailable but on the contrary, magnesium oxide has good bioavailability.
  7. Magnesium citrate is highly soluble in water but magnesium oxide is not soluble in water, it is insoluble.


Magnesium citrate and magnesium oxide can get consumed as dietary supplements. Our body needs the right amount of magnesium to function well without any complications or diseases.

Both can get used in offering relief from constipation. Magnesium citrate is more of a laxative whereas magnesium oxide is more used as an antacid.

Both share one similarity that is both has a negative effect on health when they are taken in a great quantity. So it is necessary to keep the amount limited.

The right type of magnesium should always get chosen with the help of a healthcare professional. They will prescribe the right one for you, keeping your medical history in mind.


  1. https://www.sciencedirect.com/science/article/pii/S002253471739924X
  2. https://www.tandfonline.com/doi/abs/10.1080/07315724.1990.10720349
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