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Are Your Supplements Causing Diarrhea?

Medically reviewed by 
Are Your Supplements Causing Diarrhea?

Diarrhea is a bothersome condition that affects many people; in fact, there are about 179 million cases of acute diarrhea each year. Numerous things may cause diarrhea, including dietary supplements. This article will discuss diarrhea, its symptoms, and the top supplements that can cause diarrhea. A functional medicine approach to investigating diarrhea involves a review of current supplements, testing for the root cause of diarrhea, and holistic treatment options.


What is Diarrhea?

Diarrhea is a condition of the gastrointestinal tract characterized by loose, watery stools occurring three or more times per day. Diarrhea can be acute (lasting one to two days), persistent (lasting two to four weeks), or chronic (lasting more than four weeks). Diarrhea can lead to dehydration and malabsorption of nutrients.

What are the Symptoms of Diarrhea?

Diarrhea symptoms include:

  • Loose, watery stools
  • Bloating
  • Cramping
  • Nausea
  • Vomiting
  • Urgency
  • Blood in the stool
  • Mucus in the stool

Top Supplements That Cause Diarrhea

There are several supplements that can cause diarrhea, especially when taken in high doses or when taken for an extended period. Here are some of the top supplements that can cause diarrhea:


Magnesium is an essential mineral that plays a vital role in many bodily functions. However, taking too much magnesium in supplement form can cause diarrhea, abdominal cramping, and other gastrointestinal issues. There are some magnesium types that are gentler on digestion and better for patients who suffer from loose stools.

Aloe Vera

Aloe vera has been used for centuries as a topical aid for wound health. Because of Aloe's tissue healing properties, it has also been used for internal tissue damage, including gastritis, ulcers, and gastroesophageal reflux disease (GERD). Additionally, some use Aloe for constipation, as it has a laxative effect in high doses, potentially leading to diarrhea.

Omega 3 Fatty Acids

Omega 3 fatty acids are required by every cell in our body. A central part of our cell membranes, omega 3s, affect the production of inflammatory and blood clotting markers and more. Omega 3s may benefit cardiovascular and nervous system conditions as well as inflammatory conditions. However, omega-3s can cause diarrhea, especially at higher doses.

Coenzyme Q10

Coenzyme Q10 (CoQ10) is found in tissues of the heart, kidneys, liver, and pancreas. CoQ10 has antioxidant properties and plays a role in energy production. CoQ10 is used as a supplement for certain muscle conditions, cardiac conditions, nerve pain, migraines, and more. Diarrhea can be a side effect of CoQ10 supplementation, and dividing the recommended dose throughout the day is recommended to lessen the chance of side effects.

Medium Chain Triglycerides

Medium-chain triglycerides (MCTs) have grown in popularity due to the ketogenic diet. As their name implies, MCTs are medium-chain fats with a fast absorption rate and thus can convert quickly into energy. MCTs may be beneficial for weight loss and fatigue, but high doses, or even small amounts taken by those who do not consume a decent amount of fat on a regular basis, can lead to diarrhea.

B Complex

B complex supplements usually contain eight b-vitamins: thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folic acid (B10), and cobalamin (B12). B-complexes are often taken to increase energy levels and cognitive functioning and as cancer prevention. Diarrhea can occur from the combination of high doses of multiple B vitamins.

Functional Medicine Labs to Test for Root Cause of Diarrhea

Functional Medicine Practitioners rely on functional lab testing to get to the root cause of diarrhea. Below are some of the most common labs run:

Micronutrient Panel

Micronutrient panels, such as Vibrant Health's Micronutrient Panel, analyze numerous vitamin and mineral levels. Micronutrient testing can be useful in cases of diarrhea, as both low and high levels of specific micronutrients can cause or contribute to diarrhea. Additionally, micronutrients play a vital role in the proper functioning of the GI tract.

Comprehensive Gut Testing

Comprehensive gut testing, such as GI360 by Doctor's Data, shows markers that represent numerous processes of the GI. Digestion and absorption, permeability, and inflammatory markers are given. Additionally, an in-depth analysis of the microbiome is provided. The microbiome is a collective group of microbes that inhabit the large intestine and affect digestion and absorption, hormone and neurotransmitter synthesis, immune modulation, and more. Therefore, comprehensive gut testing is generally warranted for conditions of the GI tract, including diarrhea.

Integrative Nutrition for Diarrhea

The BRAT diet can be beneficial in the case of acute diarrhea caused by stomach viruses or supplementation discussed above. The BRAT diet consists of bananas, rice, applesauce, and toast and has also been deemed the “bland” diet due to the lack of flavor in the foods. It's important to note that the nutrition component of these foods is low, and thus this is not recommended for longer periods of time. Instead, limiting fatty foods, fried foods, high sugar, and dairy may be the best option. Additionally, caution should be taken with fiber. Fiber comes in two forms, soluble and insoluble. Insoluble fiber tends to increase GI tract motility, worsening diarrhea. On the other hand, soluble fiber can slow motility in the GI and can also help to form stools. Sources of soluble fiber include oatmeal, sweet potatoes, figs, and avocados.

Hydration is imperative in cases of diarrhea. Diarrhea causes the loss of fluids, often leaving people dehydrated. Increasing fluid intake and adding in electrolytes can help avoid dehydration and replenish bodily fluids.

Probiotics for Diarrhea

Probiotics are supplements that contain strains of beneficial microbes naturally found in the microbiome. Probiotics may be helpful in the treatment of many types of diarrhea, including pediatric acute infectious diarrhea, antibiotic-associated diarrhea, inflammatory bowel disease (IBD) induced diarrhea, and irritable bowel disease (IBS) induced diarrhea. Specifically, the yeast Saccharomyces boulardii and bacteria Bacillus, Lactobacillus, and Bifidobacterium have most commonly been studied for diarrheal diseases.

Prebiotics for Diarrhea

Prebiotics are insoluble fibers that serve as food for microbes in the microbiome. Pectin, a type of prebiotic, has been shown to improve diarrhea in those with IBS where diarrhea is dominant (IBS-D) and children with persistent diarrhea.

L-Glutamine for Diarrhea

L-glutamine is an amino acid used throughout the body. In relation to the GI tract, L-glutamine serves as the primary fuel source for enterocytes, the small intestine cells. A randomized, placebo-control trial assessed glutamine supplementation in over 100 children with diarrhea. Results showed that L-glutamine shortened the duration of diarrhea as opposed to the placebo group.

Herbal Medicine for Diarrhea

Botanical medicines are extracts from plants that have medicinal actions. In a systematic review assessing herbal medicines to treat various gastrointestinal disorders, carob bean juice, Matricaria chamomile, and Potentilla erecta showed effectiveness in reducing diarrhea.

Another study showed that a combination product including myrrh, coffee, charcoal, and chamomile improved diarrheal symptoms in patients with IBS, IBD, and acute inflammatory disorders.


Diarrhea can be an uncomfortable condition affecting a person's quality of life. The root cause of diarrhea should always be investigated, and due to the high use of supplements in the United States, supplement causes of diarrhea should be considered. Functional medicine testing can help to identify the cause of diarrhea, and treatment options, including diet and supplementation, can help in recovery.

Lab Tests in This Article

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