The use of glucomannan has increased in recent decades, due to its many potential benefits, but there are also a few possible health risks to consider.
What is Glucomannan?
Glucomannan is a polysaccharide commonly isolated from various roots as a powder and used as a dietary supplement for various purposes. The most well-known source of this type of fiber is from the konjac plant, which is native to Southeast Asia. In that region, and in similar tropical locales, glucomannan powder has been in use for hundreds, if not thousands, of years in traditional medicine. Only since the 20th century, it gained popularity in America and Europe due to the potential benefits of this fibrous powder.

Keeping track of your weight. Photo Credit: Shutterstock
It is often used as a thickener or binding agent and is appearing more and more frequently as an ingredient in certain foods. While anecdotal evidence points to a wide range of benefits from this powdered fiber, there are some contraindications. The FDA has not certified its use for any medicinal purposes, but other countries and natural healers strongly support its moderate and responsible use.
Glucomannan Benefits
The many possible health benefits of glucomannan include prebiotic effect, weight loss, regulating blood sugar levels, balancing thyroid activity, treating gastrointestinal disorders, and reducing cholesterol levels, among others.
Weight Loss
There have been many recent claims and products featuring glucomannan for the maintenance of weight, and while there is some debate over the efficacy, this addition of fiber to the diet can increase feelings of fullness. [1]
Constipation
Fiber is extremely important for overall gut health, but for constipation, it can start peristaltic motion and renew normal bowel function. [2]
High Cholesterol
Studies have found that supplementation with this fiber can lower overall cholesterol and triglyceride levels, which can help prevent atherosclerosis, hardening of the arteries, and coronary heart disease. [3]
Gut Health
If you suffer from the leaky gut syndrome, ulcers, chronic inflammation or other gastrointestinal disorders, using this supplement is believed to be a natural and effective solution. [4]
Overactive Thyroid
If you have an overactive thyroid gland, it can wreak havoc on your body, leading to weight loss, fatigue, and various metabolic issues. This supplement can reduce thyroid hormone production and normalize your life. [5]
Prebiotic
This is considered a prebiotic, capable of improving the health of your microbiome by protecting beneficial bacteria. [6]
Glucomannan Dosage
Depending on what your health goals are, your daily dosage may shift, but generally speaking, you should take between 1 gram and 12 grams of this powdered supplement per day. Typically, very few side effects are registered or reported at dosages of under 5 grams per day. Before adding any powerful supplement to your diet, it is wise to speak with your doctor about potential complications with pre-existing conditions or medications.
Glucomannan Supplements
When it comes to the daily use of glucomannan, there aren’t many options besides taking a supplement of this powdered fiber, which can come in a capsule form or as a loose powder that can be added to water. However, it is very important to follow the instructions carefully, particularly if you are taking it in a powdered form. You need to ensure that you have enough water, as the powder can represent a choking hazard if too little water is consumed with it.
Glucomannan Side Effects
The major side effects of using glucomannan include the following:
- Bleeding disorders
- Stomach problems
- Low blood sugar
- Drug interactions and choking risk
Most of these problems occur if an excessive amount is taken, or if you are already taking blood-thinning or diabetic medications. This is a form of fiber, so it can affect your gut in many ways and may cause bloating, flatulence, diarrhea or constipation in some people. Pregnant and breastfeeding women are recommended to avoid this supplement.