National Institutes of Health: “Magnesium.”
The Health Benefits of Magnesium Citrate
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.
Updated on October 04, 2022
Jay Yepuri, MD, MS, is a board-certified gastroenterologist and a practicing partner at Digestive Health Associates of Texas (DHAT).
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:
- Treating occasional constipation
- Treating acid indigestion
- Clearing the large intestine of stool before a test, such as a colonoscopy, or an operation on the digestive system
Magnesium citrate can be bought without a prescription in a drug store, or it may be prescribed.
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:
- A heart condition
- A bowel obstruction
- Low calcium levels
- Low sodium levels
- Myasthenia gravis
- Neuromuscular disease
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.
Summary
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.
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.
- MedlinePlus. Magnesium Sulfate, Potassium Sulfate, and Sodium Sulfate.
- Chang J, Mclemore E, Tejirian T. Anal health care basics. Perm J. 2016;20(4):15–222. doi:10.7812/TPP/15-222
- Guerrera MP, Volpe SL, Mao JJ. Therapeutic uses of magnesium. Am Fam Physician. 2009;80(2):157-62.
- U.S. National Library of Medicine ToxNet. Magnesium Compounds.
- Poison Control. Get Poison Control Help.
- University of Connecticut Health. Colonoscopy Preparation Instructions – Magnesium Citrate.
- MedlinePlus. Magnesium Citrate.
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.
Health Benefits of Magnesium Citrate
Magnesium has been referred to as “the forgotten electrolyte”. Like sodium, potassium, and calcium, magnesium becomes a positively charged ion (cation) in the body, where it is responsible for enabling and regulating muscular function. Magnesium is the fourth most abundant cation in the body, and is found in every tissue in the body.
Magnesium citrate is a form of magnesium often taken in supplement form. Magnesium citrate is a salt, an ionic compound, that contains positive magnesium ions and negative citrate ions — the same negative ions that form citric acid when combined with positive hydrogen ions.
The name is ambiguous and may refer to salts that have these ions in a 1:1 ratio, a 3:2 ratio, or other ratios. Magnesium citrate is formed by combining magnesium oxide with citric acid, a reaction that creates magnesium citrate and water.
Magnesium citrate dissolves readily in water, so it may be used in powder, capsule, or liquid form. This also makes it an excellent source of dietary magnesium which absorbs readily into the bloodstream and bodily tissues.
Health Benefits
Magnesium citrate is a good source of magnesium ions that are needed throughout the body. Magnesium is needed in every tissue in the body. It works with nucleic acids to produce energy, and it is involved in more than 300 enzyme systems that regulate protein production, signal transmission in nerves and muscles, blood pressure, blood glucose, and other functions.
The health benefits of magnesium citrate include:
Digestion Regulation
Magnesium citrate causes the intestines to release water into the stool. This softens the stool and relieves constipation and irregularity. Magnesium citrate is more gentle than some of the other magnesium compounds and found as the active ingredient in many commercially available laxatives.
Muscle and Nerve Support
Magnesium is needed in order for muscles and nerves to function properly. Magnesium ions, along with calcium and potassium ions, provide the electrical charges that cause muscles to contract and that allow nerves to send electrical signals throughout the body.
Bone Strength
Magnesium citrate helps to regulate the transport of calcium across cell membranes, playing a key role in bone creation. The bones are also a reservoir that stores magnesium for the body. Approximately 60% of the body’s total magnesium is in the bones.
Heart Health
Magnesium helps to keep the heartbeat regular, by regulating conduction of the electrical signals that control the heart’s timing. Magnesium citrate is commonly used to prevent arrhythmia. Arterial stiffness is a risk factor related to atherosclerosis that can cause cardiovascular problems. Magnesium citrate helps to make the artery walls more flexible, reducing this risk.
Health Risks
It is estimated that half of the U.S. population does not get enough magnesium in their diets. This is surprising, as magnesium should be available in vegetables and other food sources. One explanation suggests that soils may have become depleted of magnesium, producing crops and vegetables that are also depleted.
Magnesium Deficiency
Magnesium deficiency can cause the following problems:
- Muscle spasms
- Fibromyalgia
- Cardiac arrhythmia
- Osteoporosis
- Migraine headaches
Under normal conditions for healthy individuals, excessive intake of magnesium citrate does not pose a health risk because the kidneys remove excess magnesium from the bloodstream.
Some people may experience diarrhea, nausea, and abdominal cramping when taking magnesium citrate supplements. If this happens, discontinue or reduce your dosage until these symptoms disappear.
Magnesium Toxicity
However, long-term use at very high doses (such as the dosages used for laxatives and antacids, which may be as high as 5,000 mg/day) may cause magnesium toxicity. Symptoms of magnesium toxicity include:
- low blood pressure
- nausea and vomiting
- facial flushing
- irregular heartbeat
- cardiac arrest
Do not take magnesium-based laxatives or antacids for more than once per week without consulting with your doctor.
Amounts and Dosage
The Recommended Dietary Allowance (RDA) for magnesium is 400-420 milligrams (mg) per day for adult men, and 310-320 mg per day for adult women. Women who are pregnant may increase this amount to 350-360 mg per day.
A normal diet will provide most of the RDA for magnesium, so most brands only recommend taking 250 mg/day as a supplement. Take capsules or tablets with a full 8 ounce glass of water and with a regular meal.
However, higher doses may be suggested if you are using magnesium citrate as a laxative or as an antacid. Follow the label directions, and do not use it as a laxative or antacid for more than 1 week without consulting a doctor.
Magnesium is readily available from food, and can be obtained from leafy vegetables, nuts, seeds, and whole grains. An easy way to remember this is to associate magnesium with fiber. In most cases, foods that are good sources of fiber are also high in magnesium.
As with all supplements, you should check with your doctor if you are considering adding magnesium citrate supplements to your diet.
Show Sources
Clinics in Colon and Rectal Surgery: “Medical Treatment of Constipation.”
Medical Sciences: “Magnesium: The Forgotten Electrolyte—A Review on Hypomagnesemia.”
Medline Plus: “Magnesium Citrate.”
National Institutes of Health: “Magnesium.”
Nutrients: “Magnesium: Are We Consuming Enough?”
Nutrients: “Magnesium in Prevention and Therapy.”
Physicochemical Problems of Mineral Processing: “Methods of Preparation of Magnesium Organic Compounds from Natural Dolomite.”
Trials: “Effects of magnesium citrate, magnesium oxide and magnesium sulfate supplementation on arterial stiffness in healthy overweight individuals: a study protocol for a randomized controlled trial.”
U.S. Food and Drug Administration: “FDA Drug Safety Communication: Low magnesium levels can be associated with long-term use of Proton Pump Inhibitor drugs (PPIs).”
USDA: “FoodData Central.”
Wiener medizinische Wochenschrift: “Significance of magnesium in cardiac arrhythmias.”
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