The Health Benefits of Magnesium Citrate

Magnesium citrate is an osmotic laxative that comes in a liquid form. It is a combination of the element magnesium and citric acid. Magnesium citrate benefits include:

Magnesium citrate can be bought without a prescription in a drug store, or it may be prescribed.

what is magnesium citrate

Verywell / Ellen Lindner

Brand names of magnesium citrate that may be recommended for constipation or bowel preparation include:

  • Citrate of Magnesia 
  • Citroma
  • LiquiPrep

This medication can increase the amount of magnesium in the body. But other forms of magnesium are available that have the same effect and do not act as a laxative.

This article will discuss magnesium citrate, how it is used, its benefits, and the side effects you may experience.

Health Benefits

Constipation is when you don't have regular bowel movements. It's a common problem that many adults experience from time to time. Some people find that constipation may even happen frequently and last a long time.

Constipation can be uncomfortable. And in some cases, it can lead to problems such as hemorrhoids or anal fissures because of straining to pass hard stools. Magnesium citrate is one of a variety of products available to treat constipation.

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

Magnesium citrate is available over the counter in many drugstores under brand names and as generics. But it should be used under a doctor's direction.

In most cases, taking magnesium citrate once in a while to treat constipation is 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 doctor.

Possible Side Effects

Some of the negative effects that people experience with magnesium citrate include:

  • Abdominal discomfort
  • Nausea
  • Gas
  • Cramps

These symptoms are 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 doctor.

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
  • Rectal bleeding

Most people don't have allergic reactions when they take magnesium citrate.

It’s important to let the doctor know about any other medications you're taking, especially:

  • Digoxin (brand names: Cardoxin, Digitek, Lanoxicaps, and Lanoxin)
  • Sodium polystyrene sulfonate (brand names: Kalexate, Kayexalate, Kionex, and SPS)

You should also tell your doctor if you are taking antibiotics such as Vibramycin (doxycycline), Achromycin V or Sumycin (tetracycline), Amzeeq (minocycline), Levaquin (levofloxacin), or Cipro (ciprofloxacin). This is because magnesium citrate may make these medications less effective.

Usually, taking these medications and magnesium citrate two or three hours apart can help avoid this problem. But check with a doctor or a pharmacist to be sure.

Using laxatives too much may have some harmful effects too. In particular, overuse of osmotic laxatives such as magnesium citrate may cause too much fluid loss. This can 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:

Those who are dehydrated or on a low-magnesium diet should also avoid magnesium citrate.

Using magnesium citrate while pregnant or nursing appears to be safe. But check with your doctor before taking it.

If you accidentally take more than the recommended amount of magnesium citrate, call Poison Control at 1-800-222-1222.

Dosage and Preparation

The instructions and dosage for using magnesium citrate will be available on the bottle. 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. This is because it replaces the fluid lost 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. This product is a laxative, so it may cause diarrhea. Drinking plenty of fluids after taking it is important in order to prevent dehydration. 

When magnesium citrate is used to clear out the colon before 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 the doctor's instructions. If the large intestine isn’t cleared of stool, the doctor may need to perform the test or procedure at a later date. Then you'll have to start the process all over again.

If you have 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. Pharmacists can tell you how it should be taken. They will also let you know if there could be any potential side effects or interactions with your other medications or supplements.


Magnesium citrate is a laxative that you can buy at a drugstore without a prescription. It's used to treat constipation and acid indigestion. Doctors will also have you take it before a colonoscopy.

Magnesium citrate is mild when used in the recommended amounts. The dosage is usually 10 ounces for adults and 5 ounces for children age 6 to 12, but instructions will be on the medicine bottle. Kids under the age of 6 should not take magnesium citrate without help from a pediatrician.

Let the doctor know if you're taking any other medications as magnesium citrate can make them less effective. Some people should avoid taking magnesium citrate if they have certain medical conditions. Talk with your doctor before deciding to take it.

A Word From Verywell

Constipation is common and is usually not a reason to visit a doctor unless it is long-lasting 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.

Constipation that is occurring more frequently should be discussed with a doctor in order to talk about the most appropriate way to resolve it. It also helps your doctor find out if there is an underlying cause that needs treatment.

Frequently Asked Questions

  • How long does it take for magnesium citrate to work?

    After using magnesium citrate, it can take anywhere from 30 minutes to six hours to have a bowel movement. It's important to take the dosage exactly as described by your healthcare provider or according to the product label. If you plan to use a magnesium citrate powder mixed in cold water, the mixture should be used within 36 hours of preparation otherwise it may not be effective.

  • What should I do if magnesium citrate is not working?

    If magnesium citrate is not working, you should contact your healthcare provider. Some people's bodies might not respond immediately or at all to magnesium citrate. Your healthcare provider can help.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Chang J, Mclemore E, Tejirian T. Anal health care basicsPerm J. 2016;20(4):15–222. doi:10.7812/TPP/15-222

  3. Guerrera MP, Volpe SL, Mao JJ. Therapeutic uses of magnesium. Am Fam Physician. 2009;80(2):157-62.

  4. U.S. National Library of Medicine ToxNet. Magnesium Compounds.

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By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.