The Health Benefits of Magnesium Citrate

This over-the-counter remedy may be used to treat occasional constipation

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Magnesium citrate is an osmotic laxative which comes in a liquid form. It is a combination of the element magnesium that is bound to citric acid. Magnesium citrate can be bought without a prescription in a drug store. It may be used to treat occasional constipation, acid indigestion, or in prescribed amounts it is used to help clear the large intestine of stool before a test (such as for a colonoscopy), procedure, or operation on the digestive system.

This medication can also increase the amount of magnesium in the body, but other forms of magnesium are available which have the same effect and do not act as a laxative. Brand names of magnesium citrate that may be recommended for constipation or bowel preparation include:

  • Citrate of Magnesia 
  • Citroma
  • LiquiPrep

Health Benefits

Constipation is the infrequent passing of hard stools. Constipation is a common problem that many adults experience from time to time. Some people find that constipation can happen more frequently or become chronic. It can be uncomfortable and in some cases lead to problems such as hemorrhoids or anal fissures because of straining to pass hard stools. There are a variety of products available to treat constipation, including magnesium citrate.

Magnesium citrate works by pulling more water into the intestines, which is called osmosis. When there is more water in the intestines, stool becomes softer or even watery and is easier to pass.

Magnesium citrate is available over-the-counter in many drugstores under private and generic labels but it should be used under the direction of a physician.

In most cases, using magnesium citrate on an infrequent basis to treat constipation is going to be safe. However, using magnesium citrate on a long-term basis to treat constipation could result in other health problems. It’s recommended that magnesium citrate only be used for constipation after consulting with a physician.

What Could Be Causing Your Constipation?

Possible Side Effects

Some of the adverse effects that people experience with magnesium citrate include abdominal discomfort, nausea, gas, and cramps. There are usually mild but if severe symptoms occur, or a bowel movement doesn’t occur within about three hours after taking the magnesium citrate, it’s important to contact a physician.

More serious side effects are uncommon but can include irregular heartbeat, changes in mood, confusion, drowsiness, muscle weakness, severe diarrhea, severe abdominal pain, bloody stools, or rectal bleeding. Allergic reactions are not common with magnesium citrate.

It’s also important to let the doctor know about any other medications being taken, especially digoxin, sodium polystyrene sulfonate, or antibiotics such as Vibramycin (doxycycline), tetracycline, Minocin (minocycline), Levaquin (levofloxacin), or Cipro (ciprofloxacin), because magnesium citrate may decrease the effectiveness of these medications. Usually taking these medications two or three hours before taking the magnesium citrate can help avoid this effect, but check with a doctor or a pharmacist to be sure.

Overuse of laxatives may have some harmful effects. In particular, overuse of osmotic laxatives such as magnesium citrate may lead to too much fluid loss. This can, in turn, lead to electrolyte imbalances, especially in people who have other medical conditions such as kidney disease.

People who should avoid magnesium citrate include those who have a heart condition, a bowel obstruction, low calcium levels, low sodium levels, myasthenia gravis, neuromuscular disease, or who are dehydrated or on a low-magnesium diet.

Using magnesium citrate while pregnant or nursing appears to be safe but a physician should be consulted prior to taking it.

If more than the recommended amount of magnesium citrate is taken, call the Poison Help line at 1-800-222-1222.

Dosage and Preparation

The instructions and dosage for using magnesium citrate will be available on the bottle, but most often the dosage for constipation in adults is 10 ounces. For children 6 to 12 years old, the dosage may be 5 ounces. For children under the age of 6, seek help from a pediatrician about constipation. Drinking 8 ounces of water after taking magnesium citrate is important to replace the fluid loss from the body when more water is pulled into the intestines.

Because of the taste, some people find that magnesium citrate is easier to drink if it is chilled in the refrigerator for a while before drinking it. This product is a laxative and it may cause diarrhea, and therefore drinking plenty of fluids after taking it is important in order to prevent dehydration. 

When magnesium citrate is used to clear out the colon prior to a procedure, such as a colonoscopy, the doctor’s office will give instructions on when to start taking it. It is important to use the product according to physician instructions because if the large intestine isn’t cleared of stool, it may be necessary to postpone the test or procedure and start the process all over again.

If there are any questions about using magnesium citrate, contact the doctor’s office. A pharmacist may also be able to help with general questions about this drug such as how it should be taken and if there could be any potential side effects or interactions with other medications or supplements.

A Word From Verywell

Constipation is common and is usually not a reason to visit a doctor unless it becomes chronic or it is causing significant discomfort or pain. For many people, the first instinct to resolve constipation is to turn to an over-the-counter laxative, and in most cases, laxatives are safe to use once in a while. Magnesium citrate is mild when used in the recommended amounts, and may help result in a bowel movement. However, in larger amounts, which is prescribed by a physician to clear out the colon of all stool, magnesium citrate can cause a lot of diarrhea. Constipation that is occurring more frequently should be discussed with a physician in order to discuss the most appropriate way to resolve it and to find out if there is an underlying cause that needs diagnosis and treatment.

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