Updated: 12/08/2017

Glucomannan Review - 6 Things You Need to Know


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.

Glucomannan Readers: Click here to find out why we're giving away samples of our product, Burn HD.

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…

Products Similar to Glucomannan

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Burn HD (Sample offer)read

Are There Glucomannan Weight Loss Success Stories?

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.

Can Glucomannan Powder Cause Side Effects?

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.

Is Glucomannan 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.

What Users Are Saying

"I add it to my smoothie and a little goes a long way."

"Have not gotten used to taking it as yet. My sister and brother loved it."

"My stomach started cramping from this product."

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.

Learn More About Burn HD »
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What is a glucomannan?

Glucomannan is a sugar made from konjac plant.

How much glucomannan should I take to lose weight?

Several studies we’ve read used 1000mg of glucomannan two to three times a day.

How do I know if Glucomannan is right for me?

Choosing the right product is the #1 question asked by DietSpotlight readers. We recommend trying any product before buying it and know that finding a product with a sample offer is near impossible - so we created our own product, Burn HD, with scientifically backed ingredients.

Click here to get your sample of our powerful fat burner today.

What is glucomannan good for?

Glucomannan may be good for fighting hunger, constipation, high cholesterol and controlling blood sugar levels.

Can glucomannan cause diarrhea?

Yes. Glucomannan is fiber. Fiber naturally promotes bowel movements.

What are the side effects of glucomannan powder?

Glucomannan side effects may include diarrhea, abdominal pain, nausea, bloating and gas.

How much does glucomannan cost?

The cost of glucomannan varies, but the average price is about $10.

How should I take glucomannan?

Glucomannan can be taken multiple times a day. The product label will have detailed instructions.

How is glucomannan sold?

Glucomannan is sold in powder and capsule form.

Can glucomannan block airways?

Yes, glucomannan may block the airway if too little water is used when taking the supplement.

Should I drink more water on glucomannan?

Yes, you should drink more water on glucomannan to prevent constipation.

You might want to try Dietspotlight Burn if you’re looking for a weight loss supplement that contains clinically researched ingredients.

Glucomannan Ingredients

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 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]


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.

Summer Banks Dietspotlight Author
About the Author:

Summer Banks, Director of Content at Dietspotlight, has researched over 5000 weight-loss programs, pills, shakes and diet plans. Previously, she managed 15 supplement brands, worked with doctors specializing in weight loss and completed coursework in nutrition at Stanford University. full bio.

36 Glucomannan Reviews

  • 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.

  •  JULIE (Verified User)


    • Glenn (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.

  • 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.

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

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

    • erika

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

      • Marilyn

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

  • Dody

    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.

    • Everly

      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. 🙂

  • 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.

  • 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)

    • Glenn (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.

  • Eva

    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.

  •  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.

    • Ronald

      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?


    • Your Name

      go on dr.oz sites

  • How do you use this?


    • Tina

      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?

  •  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.

    • Sue

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

    • mitzi

      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 !

  •  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?

    • fred

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

    • kmfitzsimons

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

    • Maribel (Editor)

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