Shiritaki Noodles


If you’re interested in losing weight, you’ve probably considered adding more fiber to your diet. After all, study after study has shown that dietary fiber can aid in safe, long-term weight loss (1). 

With this in mind, some people on weight-loss programs incorporate glucomannan into their diets. While the name may be unfamiliar, the history behind the supplement is well established. 

What is Glucomannan?

Glucomannan is a water-soluble dietary fiber derived from the large, starchy root of the konjac plant, known as the “corm.”

Konjac root has long been used in China, Japan and Southeast Asia for both cooking and medicinal purposes. Flour made from konjac corm is used to make foods such as shirataki noodles, which have become a popular low-calorie, gluten-free alternative to pasta.  

In traditional Chinese medicine, a gel made from konjac root flour has been used to treat asthma, respiratory problems, skin disorders and other ailments for more than 2,000 years (2).  

More recently, purified konjac flour has been used to make dietary supplements that harness the potent root’s therapeutic properties. 

Glucomannan Benefits

In combination with a healthy diet and lifestyle, glucomannan is thought to provide a number of health benefits. 


One of glucomannan’s most popular uses is for weight loss. As an all-natural fiber, it expands in the gut and creates a feeling of fullness.  

“Fiber is helpful for weight loss because it can help keep you full for several hours, is generally low in calories and can help move things along in the intestines, allowing you to move your bowels and feel lighter,” says Amanda A. Kostro Miller, a registered dietitian who serves on the advisory board for Smart Healthy Living.

Studies have supported glucomannan’s role in weight reduction. In a study of 160 overweight adults, those taking glucomannan supplements while eating a balanced diet lost significantly more weight than those who were given a placebo (3). 


As a bulk-forming natural laxative, glucomannan is sometimes used to relieve constipation. A 2006 study found that small doses of the supplement improved bowel movements in chronically constipated adults by 30 percent, while also improving gut bacteria (4

It’s important to note, however, that too much dietary fiber can actually cause gut problems. When taking a glucomannan supplement, it’s advisable to drink plenty of water to keep things moving. “Too much fiber in any form, food or supplements, can lead to constipation if someone is not adequately hydrated,” says Miller. 

Blood Sugar Regulation

By delaying the digestive process, glucomannan can lead to slower sugar absorption and naturally lower blood sugar levels after meals. In a study of high-risk patients with type 2 diabetes, participants who consumed glucomannan-enriched biscuits with meals experienced lower blood sugar levels, improved lipids and reduced blood pressure (5). 

If you have diabetes, talk with your doctor before using glucomannan or any fiber supplement.  

Cholesterol Reduction

Soluble fibers have long been prescribed to reduce cholesterol. Because soluble fiber isn’t absorbed by the intestine, it can bind to cholesterol while in the gut and remove it from the body. According to studies by the National Institute of Health, adding 5-10 grams of fiber a day can help reduce LDL, also known as “bad cholesterol” (6). 

Glucomannan has been shown to be particularly effective in lowering cholesterol. A 2017 study published in the American Journal of Clinical Nutrition found that 3 grams of glucomannan taken daily for four weeks can reduce LDL by 10 percent (7). 

Improved Skin

Like other forms of fiber, glucomannan is a natural prebiotic, meaning that it helps “fertilize” the gut and promotes healthy bacteria colonies. Glucomannan is thought to be particularly effective at reducing some of the harmful bacteria associated with acne, and is used in traditional Chinese medicine to promote skin health. A 2013 study found that when applied topically, glucomannan significantly improved the appearance of mild to severe acne (8). 

How to Use Glucomannan as a Supplement

Glucomannan supplements are available in both capsule and powdered forms. Many people are familiar with Lipozene, a brand-name supplement that uses glucomannan as its sole active ingredient. 

Glucomannan powders can be added to smoothies or shakes, or simply taken with water. Powdered forms are best for experienced users who understand how their bodies react to glucomannan and want to fine-tune their portions. A little goes a long way, with the average recommended dose around 2 grams, or a half-teaspoon. 

Glucomannan capsules are available in a range of doses, including 575 mg, 665 mg and 1,000 mg doses. Those who are new to glucomannan are advised to start with a small dose, as the feeling of fullness may be intense.

To enjoy the appetite suppressing effects of glucomannan, supplements should be taken 30-45 minutes before meals. All glucomannan supplements should be taken with plenty of water to prevent constipation or discomfort. Never consume powdered glucomannan dry—when swallowed without water, the powder can rapidly expand in the throat, causing a blockage and choking. 

While fiber supplements are effective for some, they’re not a substitute for a balanced, fiber-rich diet. “It’s best to obtain fiber from foods like fruits, veggies and whole grains,” says Miller. 

Glucomannan Side Effects

Although considered a safe weight loss aid, glucomannan does have potential side effects, some of which are serious. 

As a bulking agent, glucomannan can lead to cramping, bloating and general abdominal discomfort. Diarrhea can occur, as can constipation, especially when not consumed with enough water. Because glucomannan can lower blood sugar levels, it may be dangerous in combination with drugs used to treat diabetes.

People with diabetes, women who are pregnant or breastfeeding and children should only use glucomannan under the direction of a doctor. 

Where to Buy Glucomannan

Glucomannan supplements are becoming more mainstream, and are now available at a wide variety of retailers.

However, it’s important to do your research and trust both your retailer and supplement brand. The FDA classifies supplements as foods, so unlike prescription medications, their formulations aren’t carefully monitored. 

“One thing to keep in mind is that the supplement industry is somewhat unregulated by the FDA,” says Miller. “Supplements that you see on the shelf do not necessarily have to be tested for efficacy and potency.”

You can get glucomannan right here at LuckyVitamin, where we handpick natural products we believe in.

Here’s what LuckyVitamin customers are saying in glucomannan reviews:

“This fiber is very effective for me—I add it to my smoothie. Great product for a great price.” –Troy, OK
Product: Glucomannan Pure Powder from Konjac Root by NOW Foods

“I find it to absolutely work as recommended. I feel much fuller during the day and I’ve cut my meal size down by a third.” – Angela, NM
Product: Glucomannan 575 mg. Capsules by NOW Foods

“Great fiber for improving intestinal motility and also reducing cholesterol!” – Katherine, UT
Product: Glucomannan Pure Powder from Konjac Root by NOW Foods

“I use this to increase my daily fiber intake and to curb hunger between meals. Highly recommended.” – Kimberly, MI
Product: Glucomannan 575 mg. Capsules by NOW Foods


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