1. Home
  2. / CL Answers
  3. / I started taking a magnesium supplement (400 mg from magnesium oxide) and developed diarrhea. Might there a problem with the supplement?

Our Members Asked:

I started taking a magnesium supplement (400 mg from magnesium oxide) and developed diarrhea. Might there a problem with the supplement?

Reviewed and edited by Tod Cooperman, M.D. cooperman.png

Initially Posted: 05/15/2018

Recent CL Answers

Answer:

You are taking too much magnesium from a supplement, and diarrhea is known side effect of exceeding the Upper Tolerable Intake Level (the "UL") for magnesium when taken as a supplement. Magnesium that occurs naturally in foods does not cause this. Supplements should only be used to help you get to your requirement. If you must take a high amount of magnesium for medical reasons, certain forms are less likely to cause diarrhea than others. 

For details see the Dosing and how to take section of our Magnesium Supplements Review. Also see our Top Picks among products -- covering moderate-dose as well as high-dose magnesium (in the form less likely to cause diarrhea).

Join today to unlock all member benefits including full access to all CL Answers and over 1,300 reviews.

Join Now

Join now at www.consumerlab.com/join/

2 Comments

Related CL Answers (8)

Do magnesium creams, sprays and oils help with muscle pain and cramps? How about supplements?

Find out if magnesium oils, creams and sprays, such as BetterYou, really work to help fibromyalgia, muscle pain, cramps, relaxation or sleep. ConsumerLab.com's answer explains.

What are the side effects of magnesium supplements?

Info on magnesium supplement side effects, such as stomach upset, nausea and diarrhea. Learn about magnesium dosage, safety and drug interactions. ConsumerLab.com answer explains.

What is the benefit of magnesium orotate compared to other forms of magnesium?

Find out if magnesium orotate is the best form of magnesium for supplements, including safety concerns. ConsumerLab's answer explains.

Is it important to take calcium and magnesium together?

Should you be taking calcium and magnesium together? Find out how to ensure optimal absorption of both calcium and magnesium by following these guidelines. ConsumerLab's answer explains.

Do magnesium supplements, like Magtein, help memory or protect against Alzheimer's disease?

Magtein, and other magnesium supplements, may help memory and protect against Alzheimer's disease. ConsumerLab's answer explains.

Which vitamins and minerals should be taken together or separately?

Find out the best way to take vitamins and minerals and which vitamins and minerals should be taken together or separately for proper absorption. ConsumerLab answer explains the best way to take vitamins and minerals .

Which is the best form of magnesium to take - one that contains the most magnesium and is best absorbed?

Info on which is the best form of magnesium supplements to take and what to look for when choosing the best magnesium supplement. ConsumerLab.com explains.

Is it true that magnesium bisglycinate from BioSchwartz is less likely to cause a laxative effect than other forms of magnesium?

Find out if the Magnesium Bisglycinate from BioSchwartz is better than other forms of magnesium and how much magnesium this product contains. ConsumerLab.com's answer explains.

Related Reviews (1)

Magnesium Supplements

Join the conversation

Stephen19542
April 19, 2020

Which foods are high in magnesium? I cant take a supplement because of the laxative affect. And Ive tried different levels of milligrams.

ConsumerLab.com
April 20, 2020

Hi Stephen - Please see the ConsumerTips section of the Magnesium Review for a list of foods that are good sources of magnesium https://www.consumerlab.com/reviews/magnesium-supplement-review/magnesium/#using.

Ann16846
May 16, 2018

I had that same problem. When I had an evaluation by an alternative nutritionist I was told that certain forms of magnesium cause diarrhea. I was advised to take magnesium glycinate. Have been supplementing with that form for years now and never had the same problem.

Join today to unlock all member benefits including full access to CL Answers

Join Now

Join now at www.consumerlab.com/join/