Updated: 07/11/2017 - Site sponsored by Dietspotlight Burn

Glucomannan Review- Does This Ingredient Work?

  • 39 User Comments
  • Rating: 3.5. From 104 votes.
By Summer Banks Jun 17, 2017

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 ingredient, possible 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.

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What is Glucomannan?

To begin with, glucomannan is a water-soluble dietary fiber [1] extracted from the root of the konjac plant [2]. When consumed, it works to potentially suppress appetite, improve digestion, support healthy cholesterol [3] and blood glucose levels and promote weight-loss [4]. It’s used in supplements, drink mixes and added to foods.

Glucomannan is available at online retailers and local grocers. There is no official website because it is an ingredient that can be used by any manufacturer. We like that it’s natural and included in healthy eating plans. There are several benefits to this, and other forms, of fiber [5], 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. “Based on some research, this water-soluble fiber may help some users battling obesity [6].”

“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.

Glucomannan Side Effects – “Concerning?”

According to customer reviews glucomannan side effects [7] 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.

We take great pride in the detailed research that goes into every review we complete. With glucomannan, it’s not hard to find science and there are proven benefits, but weight-loss is about more than slowing digestion or fighting hunger. If the dieter goes into taking this supplement thinking it will stop hunger all together, they will be disappointed.

The Science – “Researched?”

There’s a wealth of research available relating to glucomannan. In studies, participants did notice changes in their weight [8]. What we found was that dieters also made changes to their existing eating habits; which could have been the cause of their weight-loss. We also found results that link it to reduced cholesterol [9], including LDL (low-density lipoprotein) and positive effects on blood glucose [10]. At DietSpotlight, solid science is a critical part of the review process. With this ingredient, there’s evidence it works [11], 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 readily available. It’s also a nice change to see some science out there that shows it can support health, related to select medical conditions. We’re also all about the appetite-suppressing benefits of fiber, but we are still skeptical. Fiber intake is critical to colon health, satiety and healthy body weight, but you can get better quality if you choose food sources rather than supplements.

If you’re interested enhancing your weight-loss, we suggest going with a supplement that’s backed by research, contains ingredients connected to weight-loss and no mention of harmful side effects.

Among the best products we’ve seen this year is one called Dietspotlight Burn. The supplement contains four clinically-tested ingredients that have been shown to help ignite fat loss and accelerate metabolism. While no one it talking about harmful side effects, the chatter from users centers on them seeing great results.

Also, the makers of Dietspotlight Burn are so confident in their supplement, that they’re offering a Special Trial Offer.

Previous Glucomannan Review (Updated July 7, 2014):

Glucomannan: What You Should Know

Glucomannan 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. You might want to consider Forskolin Fit Pro if boosting metabolism, building lean muscle muscle to burn off excess fat is your goal.

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.

Advantages of Glucomannan

  • 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.

Disadvantages of Glucomannan

  • 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.

What's the Conclusion on Glucomannan

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 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
Glucomannan2000 mg*
Konjac Root**

Other Ingredients: Vegetable capsule

Glucomannan Side Effects:

Glucomannan is a natural dietary fiber. It’s widely considered healthy and safe to consume. However, everyone’s body is unique. You never know when you might react adversely to a specific supplement. Some users of glucomannan have reported the following rare side effects.


When you’re bloated, your abdomen swells up. Sometimes, this swelling is visible. Your stomach may be hard to touch. Bloating makes you feel uncomfortable, sluggish, and heavy. It can be associated with stomach pain and nausea.

What causes bloating?

Bloating is normally the result of a problem with your digestion. Indigestion and gas are two of the prime culprits. You may also have a food intolerance you didn’t know about. Illnesses known to cause bloating include appendicitis, Crohn’s disease, irritable bowel syndrome, and viral or bacterial gastroenteritis.


Nausea is the disconcerting feeling of having to vomit. Typically, your stomach has minor spasms or convulsions. That’s because it’s trying to empty its contents. For many, this results in vomiting. It’s also common for you to experience sweating, stomach pain, and fatigue when you’re nauseous. You may get dizzy or light-headed.

What causes nausea?

Nausea has psychological and physical causes. You can become nauseous by seeing, tasting, or smelling something putrid. Often, you get nausea by eating something bad. It may be that you’re allergic to the food or that the good is spoiled. There are also many illnesses that provoke nausea, such as motion sickness, intestinal obstruction, appendicitis, and concussion. [1]

Abdominal Pain

Stomach pains can be overwhelming. The degree of pain can vary a lot. In some cases, you feel only mild discomfort. In other cases, your abdominal pain consists of very acute pangs that make it impossible to go about your daily business. It’s not uncommon for abdominal pain to be accompanied by gas, bloating, nausea, fever, sweating, or dizziness.

What causes abdominal pain?

Many conditions may be at the root of abdominal pain. It may be a case of indigestion, food intolerance, kidney stones, pelvic inflammatory disease, or stomach virus.


A case of diarrhea can ruin your entire day. You feel the need to run to the bathroom every few minutes. Forcefully expelling liquid stool is often painful. It leaves your rectum sore and dry. Diarrhea can also lead to dehydration, which is why it’s so important to drink plenty of fluids when you have “the runs.”

What causes diarrhea?

Diarrhea is provoked by viruses, bacteria, parasites, and digestive disorders like irritable bowel syndrome. [2] Glucomannan is generally safe-to-use. However, there is a still a small risk of side effects. Ask your doctor about this product before beginning use.

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[1], 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 glu 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.


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. [2]

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. However, our readers have been taking advantage of Dietspotlight Burn’s Special Trial Offer. Click above to learn more.

Glucomannan Scientific Abstracts:

Konjac Root (Glucomannan )

In an 8-week double-blind trial set out to observe purified glucomannan fiber as a food alternative in 20 obese participants. Glucomannan fiber or placebo was administered in 1g doses along with 8 ounces of water, 1 hour before each meal for three meals per day. Participants were given strict instructions not to alter their exercise or eating habits. The outcome displayed a substantial mean weight loss (5.5lbs) when taking glucomannan throughout the course of the eight weeks. Serum cholesterol and LDL were substantially decreased (21.7 and 15.0 mg/dl) within the group treated with glucomannan. There were no reports of adverse effects when taking glucomannan. [1]

The study contained a total of 53 subjects from the ages of 18 to 65 years (body mass index 25–35 kg/m2) who were randomized. The two groups did not differ in regards to baseline compliance and characteristics with the study supplement. At the eight week mark, there were no sharp contrasts between the glucomannan group and the placebo group in regards to weight-loss (−.40 ± .06 and −.43 ± .07) or any other effectiveness or safety outcomes. In conclusion, glucomannan supplement given over the course of 8 weeks showed no weight-loss promotion or solid body composition, fullness/hunger, or lipid glucose parameters. [2]

The intake of glucomannan substantially reduced total cholesterol (weighted mean difference: −19.28 mg/dL; 95% confidence interval: −24.30, −14.26], LDL cholesterol (weighted mean difference: −15.99 mg/dL; 95% confidence interval: −21.31, −10.67), body weight (weighted mean difference: −0.79 kg; 95% confidence interval: −1.53, −0.05), triglycerides (weighted mean difference: −11.08 mg/dL; 95% confidence interval: −22.07, −0.09), and fasting blood glucose (weighted mean difference: −7.44 mg/dL; 95% confidence interval: −14.16, −0.72). Intake of glucomannan failed to change any other study endpoint substantially. In conclusion, glucomannan seems to positively affect LDL cholesterol, total cholesterol, body weight, triglycerides, and fasting blood glucose, but fails to have an effect on HDL cholesterol or blood pressure. [3]

Glucomannan fibers decreased total cholesterol concentrations by 10% (P < 0.0001), triglycerides by 23% (P < 0.03), concentrations of low-density lipoprotein cholesterol by 7.2% (P < 0.007), and systolic blood pressure by 2.5% (P < 0.02). The ratio of LDL-cholesterol to HDL-cholesterol failed to show a significant change as well as high-density lipoprotein cholesterol. No changes appeared in weight or diastolic blood pressure, and no negative effects were reported. The conclusion of the study showed glucomannan as a useful adjunct for lowering cholesterol. [4]

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Summer Banks Dietspotlight Author
About the Author:

Summer Banks, a content strategist at Dietspotlight, has researched over 5000 products in the past 10 years. 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.

Rating: 3.5. From 104 votes.
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Leave a comment or review

  Is this OK while on medication?

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?

Maribel (Editor)

Hello Donna, because of possible interactions with medications, please make sure to consult with your physician before taking this product.

  Where can i buy some it?

where can i buy some at?

Devon (Editor)

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

  Can you take it with another product?

Can one take glucomannan along with Alli(orlistat)?

Maribel (Editor)

Hi Karen! Because of possible interactions with medications, please make sure to consult with your physician before taking this product.

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

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

Maribel (Editor)

Hi Marylyn! For more information on where to purchase this product, please refer to the Glucomannan official website.


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 ?


I started taking Glucomannan. I have taken fiber tablets for years because of having Diverticulitis. Having trouble with bowels and going to bathroom. Question….. should I continue to take fiber tablets with glucomannan? I think I stopped the fiber to fast and it is causing issues.


Hi Dody. Glucomannan is a water-soluble fiber. If you’ve been taking fiber for years and you have a medical condition, it’s best to ask your doctor. 🙂

Jackie Bourg

Sorry, but the message I am getting here is that people come to read about GLUCOMANNAN which is also highly rated (as per DR OZ) and then you “down it’ to promote your own product?

Richard (Editor)

Hi Jackie. I apologize if it appears as if we downed glucomannan. We provided links to published research and provided information so people can make an informed decision. If you did notice anything out of sorts, please let us know and we will immediately address. Thank you.


I just started taking it and i must say i love it. 2×3 and i feel great no hunger at all. Felt full all tge time and only eat fruits and vegies for vitamins. I pray I loose some pounds soon.

  Where was it extracted?

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

Devon (Editor)

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

  Doesn't seem to be working
JULIE (Verified User)


Richard (Editor)

Hi Julie. Sorry to hear about this ingredient not working. If you’re looking for a boost to your weight-loss, you may consider one like Dietspotlight Burn. Click above to learn about the sample offer.

  Glucomannan is not banned in Australia.
William (Verified User)

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!

Jackie Bourg

If you swallow the capsules with sugar free apple or any fruit “compote”, it will slide without problems, HOWEVER, follow it with 1 bottle of water (equivalent of 2 cups)

  How to take this?



go on dr.oz sites

  How do you use this?



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.

  Does it work?

is it working?

  I hope it works
Madeleine (Verified User)

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)

Richard (Editor)

Hi Madeleine. We’re hoping it works as well. If you want to boost your results, you may want to consider one with clinically-tested ingredients like Dietspotlight Burn. Click above to read more about the sample offer.

  They're great for diabetics and low carb dieters.
The Mom (Verified User)

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.


a thank you to the Mom for her input I’ve been looking for a thickener I started on the THM plan but it got kind of pricey so my daughter and I are now starting on the Atkins and I really needed a thickening agent for when we make roast for gravy for smoothies etc. thank you so much !


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

  I also will try cutting down on the dosage.
NancyA (Verified User)

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.

  Very effective with proper exercise
kris (Verified User)

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!

  Loved using it
CSJ (Verified User)

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.

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

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

Maribel (Editor)

Hello Frank, because of possible interactions with medications, please make sure to consult with your physician before taking this product.


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


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