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Glucomannan Review - Does This Ingredient Work?

By Summer Banks on Sep 24, 2016
Glucomannan Review

Looking at some diet products can be painful, especially if there’s no backing for the formula. Let’s find out if glucomannan is in this group. Our detailed review focused on the ingredients, side effects and scientific research. Additionally, we picked apart hundreds of user comments and testimonials. Then, we summarized and condensed to give you the info you need.


What is Glucomannan?

To begin with, glucomannan is a water-soluble dietary fiber extracted from the root of the konjac plant. When consumed, it works to potentially suppress appetite, improve digestion and promote weight-loss. It’s used in supplements, drink mixes and added to foods.

Glucomannan is available at online retailers and local grocers. We like that it’s a natural ingredient and included in healthy eating plans. There are several health benefits to this fiber, but read on…

Lack of Results – “No Changes in Weight?”

The first concern with glucomannan was the lack of results. “Adding fiber to your diet could improve overall health and wellness,” said our Research Editor. “But, research proving you’ll lose weight isn’t that solid.”

“Minimal results and way too slow,” said a user.

“I just started taking this about 2-3 days ago. I didn’t notice a difference in my appetite,” stated another.

While some dieters didn’t notice results, others reported solid results while using glucomannan.

“Since taking this drug, I have lost 3 lbs in one week. I only take 2 pills 1/2 an hour before dinner,” reported a consumer.

Side Effects – “Concerning?”

According to customer reviews glucomannan side effects were concerning. “I got very nauseous to a point that I threw up after 15 min. of taking this pill,” said customer.

“Up all night sick now left with a huge migraine,” commented another.

Side effects from natural ingredients are rare. We found some users that didn’t notice any adverse reactions.

“I took it this morning and I feel great. Little pain in my side but it went away quickly after drinking water,” said a dieter.

“I feel fuller and no constipation. No side effects,” reported another.

Our research has shown that when there’s any part of a supplement that’s concerning, such as being the cause of adverse reactions, the chances of long-term success are reduced. It may be time to consider an alternative, if you use glucomannan and experience negative side effects.

The Science – “Research Based?”

There’s a wealth of research available relating to glucomannan. In studies, participants did notice changes in their weight. What we found was that dieters also made changes to their existing eating habits; which could have been the cause of their weight-loss. At DietSpotlight, solid science is a critical part of the review process. With this ingredient, there’s evidence it works, but it may not be the only option.

The Bottom Line – Does Glucomannan Work?

Ladies and gentlemen, what’s the final word on glucomannan? We like that it’s affordable and that it’s readily available. We would have liked to see more research connecting it to weight-loss. Another concern relates to customer comments talking about the lack of results and potential side effects.

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About the Author:

Summer Banks is an ISSA-Certified Fitness Nutrition Specialist and has reviewed over 2000 diet products. She has years of nursing training, experience as a manager responsible for 15 supplement brands, and completed coursework on Food and Nutrition from Stanford University. full bio.

How Does Glucomannan Compare?

Previous Glucomannan Review (Updated July 7, 2014):

What You Should Know

Glucomman is a water soluble dietary fiber that is derived from the Konjac root. It is a dietary fiber that helps increase a user's stool bulk by absorbing water. This helps the stool move more easily through the colon. Basically, it is a fiber that expands in the stomach and absorbs fats. The absorbed fats are eliminated from the body and do not undergo digestion, thus nullifying the calorific effect.

List of Ingredients

Glucomannan is a popular ingredient derived from the Konjac Root contained in many products like lipozene and Zeal for Life. It is a natural diuretic found in many diet supplements today. It is also available in tablet form.

Product Features

Glucomannan is often recommended as a solution to obesity. It is also recommended to people who have high cholesterol, and have problems with constipation. Such is the case due to the popularity of Konjac Root, which can be found in meal replacements like Slim Stix. It should never be taken by anyone who has problems with their esophagus as it can lead to choking. It should also never be taken by someone who is diabetic unless under the supervision of their physician as it can alter the person's insulin requirements. Some Diuretics have these adverse effects. Two Glucomanan tablets of 500mg before each meal is often the recommended dose for this product. It should be taken with plenty of water, and again, if not enough water is taken, there is a risk of choking. It is therefore a product that should be ingested with care.

In trials studies, one in twenty obese patients who took capsules of purified Glucomannan sixty minutes before a meal lost 5.5 pounds after eight weeks. It does therefore seem to achieve weight loss in certain people, but there are a number of risks and side effects associated with this product. Glucomannan can be ordered on line as a supplement by itself, at an average cost of approximately $9 for one hundred tablets. Glucomannan is also a common ingredient in a number of weight loss nutritional supplements.

See Our Featured


  • It is available for purchase from online pharmacies.
  • It is relatively inexpensive.
  • There are product studies available that indicate Glucomannan can help with weight loss in certain cases.


  • We could not find an official website for Glucomannan.
  • It cannot be taken by anyone who has problems with their esophagus.
  • It can be dangerous for diabetics as it can alter the insulin
  • The sale of Glucomannan has been banned in some countries.
  • Since it is a diuretic, plan on frequently needing access to a bathroom.


There does seem to be some evidence that Glucomannan can result in a small amount of weight loss. However it seems that this supplement would need to be taken on a permanent basis if the effect is to be long-lasting, and this could have negative effects on the user's digestive system. What gives rise to concern, however, are the known side effects of this product which makes us wary of recommending this product as part of your weight loss program. This frenzied popularity is not unique to Glucomannan as other flowering plants also give rise to this same fad adaptation like Senna Tea. A number of warnings have been given by the FDA, regarding safety issues with Glucomannan. We would like to see proper controlled and standardized trials with this product over a very long time period, which assess the long term effects of taking Glucomannan and any risks involved. Until we see these tests, we need to be wary of using Glucomannan on its own and also as an ingredient in other supplements.

Glucomannan Questions & Answers:

We picked apart hundreds of user comments about glucomannan and condensed into this helpful FAQ.

What are the side effects of glucomannan?

Some potential glucomannan side effects include diarrhea, abdominal pain, nausea, bloating and gas.

What are the ingredients in glucomannan?

The glucomannan ingredient is amorphophallus konjac. Different retailers may add more to specific formulas.

Does glucomannan work?

There’s limited clinical research proving glucomannan is an effective weight-loss solution. We have found some studies, but the results were mixed.

How much does glucomannan cost?

The cost of glucomannan varies, but the average price is about $10. Typically, one bottle will last 30 days.

How should I take glucomannan?

You should take glucomannan according to the directions on the label. Some products recommend taking three capsules per day, one before each meal.

Can I take glucomannan if I have a health condition?

Women who are pregnant or nursing, anyone taking prescription medication, those with health conditions or those under 18 years of age should consult with a licensed physician prior to using dietary supplements, including glucomannan.

What do users like about glucomannan?

Some users liked the affordability of glucomannan and the availability of the supplement.

What do users NOT like about glucomannan?

We found that side effects of glucomannan were a concern and that users didn’t notice weight-loss.

How is glucomannan sold?

Glucomannan is sold as a powder and a capsule.

Can glucomannan block airways?

Yes, glucomannan may block airways if not dissolved properly.

Should I drink more water on glucomannan?

Yes, you should drink more water on glucomannan, considering the supplement could be bulk-forming.

Do I need to exercise on glucomannan?

No, you don’t need to exercise on glucomannan, but adding fitness could lead to better results.

Do you know of any special deals or discounts on glucomannan?

The special deals and discounts on glucomannan depend on the retailer selling the supplement.

Glucomannan is nothing more than a water-soluble fiber that expands when it comes in contact with liquid. It was originally marketed by some companies as an alternative to gastric bypass surgery.

Glucomannan Ingredients and Supplement Facts

Serving Size: Varies
Serving Per Container: Varies
Amount per Serving % DV
Konjac Root * *

Other Ingredients: None

26 User Reviews About Glucomannan

Leave comments below
  • 1

    let me ask:”glucomannan extraction from konjac?” thank you!


    Devon (Editor)

    Hi Uyen. Glucomannan and Konjac root are extracted from two different plants.


  • 2



  • 3

    where can i buy some at?


    Devon (Editor)

    Hi Terri. We’ve listed convenient contact info in the Q&A section.


  • 4

    The comment in the main article regarding the banning of glucomannan in Australia is incorrect. Glucomannan flour food products are approved by FSANZ and are commonly available in shirataki noodles.



    If Glucomannan is banned in Australia, why did recent trials in Australia approve acceptance of a product containing same? Is it banned and why? Have there been any cases of people choking on any product containing G? Why has a person or persons been allowed to ‘buy the rights to G’ in Australia? Terribly confusing and causing people to avoid products they really are safe to use!


  • 5



    Your Name

    go on dr.oz sites


  • 6




    I use bottled water and drink about 2 oz out (to make room at the top to add and shake the glucomannan powder. I put a pack of crystal light (any flavor) into my water and 1/2t of the powder and shake briskly so the powder does not start to gel. Drink the entire bottle right away. Drink 30+ min before a meal and see how much food you CAN’T eat..lol.


  • 7

    Can one take glucomannan along with Alli(orlistat)?


  • 8

    is it working?


  • 9

    Is there any problem using Glucomannan if you are taking Plavix for a heart condition. How does it affect the good bacteria in the intestinal tract?


  • 10

    I just bought it today at Purtains Pride Vitamin Outlet. It was 13.99 a bottle but you get 2 others free. I hope it works. :O)


  • 11
    The Mom

    I’m on a low carb diet and I use this product in powder form, not tablet. I use it just like I would corn starch or unflavored gelatin. I’ve mixed 1/4 tsp with 1 cup of chocolate Calorie Countdown milk and put it in the fridge. An hour later, I’ve got a delicious chocolate pudding that is low carb and high in fiber. I’ve used it as a gravy thickener and it tasted just like gravy made with corn starch. Most stores carry Tofu Shirataki noodles that are a blend of tofu and konjac. They’re great for diabetics and low carb dieters.



    Where do I find this Powder form glucomannan product? GNC does not carry.


  • 12

    Have been using G for about two months from VitaCost(3caps) 2000mg, so far I have found my self more regular and have lost several pounds.( I have also been cutting down on sugar)so can’t say that it is just the G. Here lately I have found myself feeling very bloated which I suppose this means it is working. After reading this article I see the importance of drinking plenty of water, I also will try cutting down on the dosage.


  • 13

    I have been taking an ‘advanced’ form of glucomannan, proplmannan by life extension and i have to say, i like it! I can see where the choking risk comes in to play, when you take it capsule form you really do have to gulp down a lot of water (carefully,but quickly), and at least a 1/2 to a full water bottle. you get the hang of it pretty quickly tho. your supposed to take medication at least 2hrs apart from it. Results wise, within the first couple of days i lost a few pounds, which surprised me considering how much water ive been drinking and how im not actually running to the bathroom. I can see how with exercise this would actually make a really nice supplement. ill keep buying it if the results remain consistent 🙂 . Love it!


  • 14

    I loved using it and lost weight but I also lost hair and muscle mass and became malnourished. I ended up short of breath and wheezing. Major health issues. Not worth it.


  • 15

    how expensive is glucomannan & can it be bought in local stores?



    You can buy glucomannan at GNC for 16.99. Super cheap and its 90 tablets



    Are you or have you used this product, if so have you lost weight with it ?


  • 16
    Frank Rivera

    How does this product inter act if a person is taking medacation for Bi-Polorism and Thyroid meds?



    i take 6 metimucal a day can i take this along with glucomannan?



    I would talk to your doctor. Even herbal supplements can effect medicine.


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