Magnesium For IBS: In-depth Doctor's Review.

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Magnesium is known for its laxative effect. It is found as supplement capsules, topical gel, and a laxative oral solution and powder.

Some linked magnesium deficiency to IBS symptoms (especially constipation). And also, some recommend magnesium supplements for IBS patients.

What you will get from this article:

  • Is Magnesium good for your IBS?
  • When to use magnesium laxative solutions for IBS?
  • When to take magnesium capsule supplements for IBS?
  • How can Magnesium HURT your IBS?
  • Signs you are low on Magnesium
  • Alternative ways to correct low Magnesium without affecting your IBS.

Magnesium is mainly found in tissues. Only small fractions are present in the blood. It serves many functions in maintaining healthy bones, muscles, and the nervous system.

magnesium distribution

Data source: this study

1- Magnesium laxatives for IBS (powder and oral solutions)

Magnesium is a wonder element, the fourth most abundant element inside your body. Magnesium citrate (oral solution) is a laxative. It is a type of laxative that is called (Osmotic laxative). 

What osmotic laxatives do is keeps water inside your intestine and prevent its absorption. Also, it may lead to the secretion of water from circulation into the intestine. This will make stool softer and produce a laxative effect for your IBS.

Magnesium citrate is an effective treatment for constipation, including IBS-predominant constipation and Idiopathic chronic constipation.

Regarding IBS, Using Magnesium Citrate oral solutions as a laxative is a late third option. This is because other options like fiber laxatives work better in alleviating symptoms of IBS other than constipation. And also, they generally will have fewer side effects profiles.

And here is a breakdown of laxative options for IBS-C in order of ?preferability?: (reference)

The first option: Soluble fiber laxatives

A trial of soluble fiber laxatives (Psyllium[Metamucil]) is recommended as the first option to try with your IBS constipation. Psyllium (Metamucil) is a soluble fiber that is found to help with IBS-Constipation. It dissolves in water inside your intestine and forms a gel that acts as a laxative. It can improve overall IBS symptoms, including abdominal pain and gas (if taken in the appropriate doses together). Also, it is a safe, natural treatment with a good safety profile and fewer side effects.

The second option: Poly Ethylene Glycol (PEG):

Polyethylene Glycol (PEG) is an osmotic laxative (like Magnesium Citrate). It is a second option if your IBS-Constipation didn’t respond to Psyllium (Metamucil).

PEG generally has fewer side effects than other osmotic laxatives (like magnesium citrate, Milk of Magnesia, and lactose).

Also, it is inexpensive and widely available. Common side effects include bloating and abdominal discomfort.

You can find the best laxative products on our resources page.

The third option: Magnesium as a laxative for IBS.

Magnesium for IBS comes third. We can use Magnesium citrate oral solution (250 mL once a time) or Milk of Magnesia (Magnesium Hydroxide) as a laxative.

It acts as PEG as an osmotic laxative. It does good work for improving your IBS constipation. But the downside is that it may induce some abdominal pain and bloat, more commonly than fiber and PEG laxatives.

Also, some people may experience nausea and gastric upset. I usually spare Magnesium powders or oral solutions to people with IBS with occasional constipation or those who fail to respond to the first two options.

2- Are magnesium capsule supplements good for IBS?

If you’re dealing with Irritable Bowel Syndrome (IBS), you might wonder: can magnesium capsules help?

The answer isn’t a straightforward yes or no. Here’s why:

1. Improving IBS Symptoms:

While Magnesium is widely used, its use for IBS isn’t clinically approved yet. Some people find that low-dose magnesium supplements (less than 300mg) can help with certain IBS symptoms, especially constipation.

Research on Magnesium for chronic constipation is promising (reference). But remember chronic constipation and IBS aren’t the same. IBS comes with a range of symptoms like abdominal pain and bloating (reference), and there’s no strong evidence that Magnesium can help with these.

2. Other Health Benefits:

Magnesium supplements can offer a variety of health benefits. But Magnesium might not be your best bet if you have IBS, especially IBS-Diarrhea, or if you consistently experience nausea.

So, Should You Try Magnesium?

If you have IBS-Constipation, you might try low-dose magnesium supplements (start with 200mg capsules once daily). But remember, always consult your doctor first.

Once you start, keep an eye on your symptoms. If they worsen, stop taking the Magnesium. If there’s no change, you can gradually increase the dose, sticking to the dose that gives you the best results with the least side effects.

Remember, everyone’s IBS is different. What works for one person might not work for another. The key is to listen to your body and adjust accordingly.

3- Health benefits of Magnesium (other than IBS)

Magnesium is a true marvel of a mineral. It’s abundant in your body, primarily tucked away inside your cells, with smaller amounts floating in your bloodstream.

This wonder mineral is crucial for a host of body functions. Whether you’re dealing with IBS or not, there’s a good chance you could benefit from more Magnesium.

The benefits of Magnesium: (reference) (reference).

General benefits of magnesium and magnesium supplements for the human body (infographic)

1. Enzyme Activation:

Magnesium is the trusty sidekick to over 300 enzymes in your body. These enzymes oversee various functions, from protein formation and muscle contractions to nerve functions, blood pressure regulation, and blood glucose control.

2. Energy Production:

Think of Magnesium as your body’s power generator. It plays a key role in energy production, helping to keep you fueled and ready to go.

3. Bone Health:

Magnesium is a key player in bone health and development. It’s like the scaffolding that helps build and maintain strong, healthy bones.

4. DNA and RNA Production:

Magnesium is involved in producing DNA, RNA, and the antioxidant glutathione. It’s like the behind-the-scenes director of your body’s genetic coding and antioxidant defense.

5. Heart Health:

Studies have shown magnesium supplements can lower blood pressure and protect against heart diseases (reference). It’s like a shield, helping to guard your heart against disease.

6. Diabetes Prevention:

Diets rich in Magnesium have been linked to a significantly lower risk of diabetes (reference). It’s like a secret weapon in your fight against this chronic disease.

7. Migraine Relief:

Low magnesium levels may contribute to migraines (reference). While research is ongoing, some studies suggest that taking 300mg of Magnesium twice daily could help prevent migraine attacks (reference).

4- Low Magnesium symptoms and their link to IBS and constipation.

Magnesium deficiency can be a silent health saboteur. It’s often overlooked, yet it can significantly impact your well-being, including your gut health.

Magnesium deficiency is surprisingly common. Studies estimate that Half the US population consumes less than the required daily amount of Magnesium (reference)

Spotting the Signs of Magnesium Deficiency:

Magnesium deficiency can be tricky to identify, as the symptoms vary. Here are some of the most common signs to watch out for:

  1. Fatigue and Muscle Weakness: Magnesium is a key player in energy production. So, when levels are low, you might feel constantly tired or weak muscles.

  2. Loss of Appetite: If you’re not as hungry as usual, it could be a sign of magnesium deficiency.

  3. Nausea and Vomiting: These are less common symptoms but can occur if your magnesium levels are significantly low.

  4. Numbness and Tingling: Magnesium plays a crucial role in nerve function. Deficiency can lead to numbness and tingling, particularly in the extremities.

  5. Muscle Cramps and Contractions: Low magnesium levels can lead to involuntary muscle cramps and contractions, often felt as a twitch or a sudden, sharp pain.

  6. Mental Disorders: In severe cases, magnesium deficiency can lead to mental disorders, including apathy and even psychosis.

The Magnesium-IBS Connection:

So, how does magnesium deficiency tie into IBS and constipation?

Magnesium is key in muscle contractions, essential for moving food and waste through your digestive tract. When magnesium levels are low, these contractions can become irregular, leading to constipation. Although there is no solid evidence or link in the research between magnesium deficiency and IBS, Magnesium is linked to chronic constipation. 

Moreover, Magnesium helps to draw water into the intestines, softening the stool and making it easier to pass. A magnesium deficiency can disrupt this process, further contributing to constipation.

8- When to take Magnesium for IBS.

Navigating the world of supplements can be tricky, especially when dealing with a condition like IBS. Let’s break down how you can use Magnesium to your advantage.

1. Magnesium Powder or Oral Solution Laxatives for IBS:

If you’re dealing with IBS-Constipation, magnesium powder, or oral solution, laxatives might be an option. But remember, these should only be considered if fiber supplements like psyllium (Metamucil) and Polyethylene Glycol haven’t worked for you.

Always consult your doctor before starting magnesium-based laxatives. They can potentially worsen other IBS symptoms like abdominal pain, diarrhea, gas, and bloating.

2. Magnesium Capsule Supplements for IBS:

Considering a low-dose Magnesium supplement for IBS? Start with a 200mg capsule once daily and gradually increase the dose. Here’s what you need to know:

  • IBS-Constipation: Magnesium may improve constipation symptoms. However, there’s no evidence that it improves other IBS-related symptoms like diarrhea, cramps, and gas.
  • IBS-Diarrhea: There’s no scientific evidence supporting using Magnesium for IBS-related diarrhea. Overuse of Magnesium may worsen IBS diarrhea. Always consult your doctor before using Magnesium if you have IBS-D.
  • IBS Abdominal Pain: While it was thought that Magnesium could relax the smooth muscles of your colon and prevent abdominal pain, there’s no scientific evidence to support this. High doses of Magnesium may indirectly increase your gut motility and pain due to its osmotic laxative effects. Use it with caution, and always consult your doctor.
  • IBS Gas and Bloating: Magnesium doesn’t seem to improve gas and bloating with your IBS unless caused by severe constipation. High doses may increase the sense of gas and bloat and cause nausea. Very high doses of Magnesium supplements have been reported to cause (paralytic ileus) in rare cases (reference).

3. Magnesium Capsules for Other Health Benefits:

If you’re considering Magnesium for its other health benefits, here are some situations where it might be beneficial:

  • IBS + Chronic Fatigue: Chronic fatigue is commonly associated with IBS and could indicate magnesium deficiency. You can try a magnesium capsule supplement even if your blood magnesium levels are normal (reference).
  • IBS + Diabetes Mellitus: Magnesium supplements are known for lowering the risk of diabetes and improving blood sugar control (reference).
  • IBS + Migraine: IBS and migraine is a common association. You may benefit from taking a magnesium supplement.
  • IBS + Osteoporosis: Magnesium is vital in promoting healthy bones and preventing osteoporosis (reference).
  • IBS + Hypertension or Ischemic Heart Diseases: Magnesium may help both conditions.
  • IBS + Alcohol Dependence: Alcohol dependence can cause magnesium deficiency. So if you consume alcohol while you have IBS, taking a magnesium supplement capsule is a good option.
  • IBS + Other Gut-Related Conditions: If you have other conditions affecting your gut together with IBS, like previous intestinal resection or fat malabsorption, taking Magnesium may improve your condition (reference).
  • IBS + Old Age: Older adults are at higher risk for hypomagnesemia (reference). So having IBS in old age may benefit from magnesium supplement capsules.

Warning: It’s not typical to have an IBS onset in older ages than 50. Always consult your doctor about your IBS and do the appropriate testing and investigations to confirm your condition.

Here is a table summary of the indications and contraindications of Magnesium in IBS: 

ConditionIndication for Magnesium Use
IBS-ConstipationIt can improve constipation symptoms. Use only if fiber supplements and Polyethylene Glycol haven’t worked.
IBS-DiarrheaNot recommended. Overuse of Magnesium may worsen IBS diarrhea.
IBS Abdominal PainNot recommended. High doses of Magnesium may indirectly increase gut motility and pain.
IBS Gas and BloatingDoesn’t seem to improve gas and bloating unless caused by severe constipation.
IBS + Chronic FatigueCan try a magnesium capsule supplement even if blood magnesium levels are normal.
IBS + Diabetes MellitusThey are known for their benefits in lowering the risk of diabetes and improving blood sugar control.
IBS + MigraineMay benefit from taking a magnesium supplement.
IBS + OsteoporosisPlays a vital role in promoting healthy bones and preventing osteoporosis.
IBS + Hypertension or Ischemic Heart DiseasesIt may help both conditions.
IBS + Alcohol DependenceIt can help with magnesium deficiency caused by alcohol dependence.
IBS + Other Gut-Related ConditionsIt may your condition improve if you have other conditions affecting your gut with IBS.
IBS + Old AgeOlder adults are at higher risk for hypomagnesemia.

5- Safety and side effects when taking Magnesium for IBS.

You have to consult your doctor before taking Magnesium for IBS. No strong scientific evidence suggests the use of Magnesium for IBS-C. Generally, a magnesium supplement is a safe OTC medicine. But it may have some side effects on your IBS if not taken properly, such as:

1- Diarrhea: frequently encountered due to its laxative effect. Magnesium supplements may worsen your IBS diarrhea.

2- Also, Magnesium in large doses may worsen other IBS symptoms like bloating and gas.

3- It may cause nausea and stomach upset.

4- Large doses may cause side effects like low blood pressure, drowsiness, and irregular heartbeats.


6- When NOT to take Magnesium for IBS?

1- IBS with diarrhea: generally not recommended to take Magnesium for IBS diarrhea. Unless prescribed by your doctor.

2- IBS + kidney disease: don’t take any magnesium supplements (unless prescribed) if you have kidney disease. This is because your kidney mainly eliminates Magnesium.

3- IBS + severe nausea: Magnesium supplements may cause gastric upset and cause nausea or vomiting. Consult your doctor if it is necessary to take a magnesium supplement. 

4- Use with caution and take 2 hours apart if you are taking Magnesium with one of these medicines:

  • Some antibiotics as quinolones, tetracyclines, and aminoglycosides.
  • High blood pressure medications such as calcium channel blockers (for example, Amlodipine)
  • Diuretics: medications that increase urine volume are used for heart diseases, hypertension, and liver diseases.
  • Muscle relaxants.
  • Bisphosphonates.
  • Thyroid medications
  • Chemotherapy drugs.
  • Other antacids. 

If using any of the above drugs, consult your doctor before taking Magnesium.

NOTE: this is not a complete list of side effects and contraindications; please refer to your doctor and read the following resources:

Magnesium (WebMD).

Magnesium (

Summary of Magnesium for IBS:

Magnesium for IBSNotes
Laxative solution and powder containing Magnesium for IBSIt can benefit IBS constipation. But it’s a late is better to use fiber laxatives like Metamucil ? or PEG. (Fewer side effects)
Capsule supplements containing Magnesium for IBS:It can benefit your IBS, especially the constipation-predominant type. But clinically proven benefits for IBS-diarrhea, pain, gas, and bloating.
Using magnesium supplements while you have IBS:You can benefit from Magnesium if you have IBS plus: chronic fatigue, migraines, diabetes mellitus risk or disease, hypertension, heart diseases, osteoporosis, or older age.
Don’t use Magnesium for IBS when: If you have severe IBS diarrhea, are taking other medications, have kidney problems, have gastric upset, or have nausea. Or magnesium supplements worsen your IBS.
Can Magnesium worsen IBS?Yes, especially in large doses. It can worsen IBS diarrhea, nausea, abdominal pain, and bloating.

FAQs about Magnesium and IBS:

Can Magnesium irritate your gut?

Yes, Magnesium can potentially irritate your gut, especially when taken in high doses or certain forms. This is particularly true for magnesium supplements that act as osmotic laxatives, such as magnesium citrate or hydroxide (also known as Milk of Magnesia).

Which Magnesium Makes You Poop?

Magnesium supplements that act as osmotic laxatives are the ones that can stimulate bowel movements. These include magnesium citrate and magnesium hydroxide (Milk of Magnesia). They draw water into the intestines, softening the stool and promoting bowel movements.

What is the Best Time to Take Magnesium for IBS-C?

There isn’t a universally “best” time to take Magnesium for IBS-C. Some people find that taking it at night helps stimulate a bowel movement in the morning, while others may prefer to take it in the morning. It can depend on your routine and how your body responds to the supplement. However, taking magnesium supplements with a meal is generally recommended to help reduce the risk of potential side effects like stomach upset.

What is the Best Type of Magnesium for IBS-Constipation?

Magnesium citrate is often recommended for constipation due to its osmotic effect on the intestines. It’s generally well-tolerated and effective at stimulating bowel movements. However, everyone’s body responds differently to different supplements, so what works best for one person might not work as well for another. It’s always a good idea to consult with a healthcare provider before starting any new supplement regimen, especially if you have a condition like IBS.