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Glucomannan: Benefits, Side Effects, And More


Have you ever observed what’s the most common health concern? Quite a few things might strike you after reading this question.

But if you think deeply, you will find out that the answer is obesity. As per statistics, around 30% of the world’s population is obese. Unfortunately, this trend is on the rise.

Even if you look around, there is always a chance of spotting an overweight individual. Since it is a massive concern, you’ll find many studies and possible solutions.

Every day you might come across several articles and home remedies recommended to shed some pounds.

Even if you keep obesity aside, fitness freaks, body goals, and trends give a push to weight loss content.

Increasing gyms, newly emerging diet plans, and even traditional remedies depict that weight loss is a hot topic.

Out of all the eye-catching solutions, today’s pick is glucomannan. This article will try to find all the essential information about it.

What Is Glucomannan?

Glucomannan comes straight to humans as nature’s boon. The roots of the konjac plant are the primary source of glucomannan.

This plant is mainly found in the Asian subcontinent. It is native to countries like China, Vietnam, and Japan.

Another name for konjac is elephant yam. It is a highly-priced plant. However, its medicinal use[1] has been widespread since old times.

The dietary fiber obtained from it is called glucomannan. It is a polysaccharide that dissolves in water.

It is available in powders, jells, supplements, and drinks mixes. Not only this, it has been used in food products. For example, recipes make use of glucomannan as a thickener.

It has about 40% dry weight of konjac. You might be familiar with it due to shirataki noodles. Glucomannan is the main content of these noodles.

Interestingly, glucomannan has an incredible water-absorbing capacity. Therefore, it converts into a gel absorbing water up to eight times its weight.

This property is believed to aid in weight loss. However, its benefits are not limited to losing weight. A list of advantages follows up.

It has been found effective for cholesterol, regulating blood sugar levels, and promoting healthy bacteria.

However, like any other worldly thing, it has some side effects. The biggest threat is its ability to expand. When it becomes a gel-like structure after absorbing water, it can cause blockage. Collapse and death are even possible.

Except for the choking hazard, bloating and diarrhea are also possible. However, as per available data, we can say that it might help with weight loss. However, more studies should be conducted regarding the safety and allergic reactions.

Benefits Of Glucomannan

As per the studies conducted, glucomannan has earned a spot in modern healthcare. Some of the benefits that emerged as a result of the studies are-

  1. Weight loss

    Glucomannan might be one of the best dietary fibers to consider. Its water-absorbing quality can explain its potential as a weight loss inducer.

    Once it absorbs water, it forms a bulky gel that sets a layer on the bowel wall. Hence, food sits in the stomach for a longer time. The exit is delayed making you feel full.

    The feeling of satiety may keep away from cravings. It also slows the absorption of sugar and simultaneously boosts digestion.

    When both the essential conditions of weight loss are fulfilled, you are likely to witness some trimming and shedding.

    Moreover, glucomannan itself is low in calories. It decreases the affinity for calories further.

    According to a study[2], after glucomannan intake, the subjects did not feel the need to have more calories afterward.

  2. May control Diabetes

    Type 2 diabetes is spreading its evil roots with each passing day. This condition develops when the body has lacked insulin or resists it.

    It is a chronic and serious problem disrupting the healthy functioning of the body. Moreover, it brings along the risk of cardiac arrest and stroke.

    Considering the risk, glucomannan might come in handy as it could slow down the absorption of sugar.

    Not only does the food pass slowly through the tract leading to less absorption, but it also keeps you full. Thus, when you lose weight, symptoms of type-2 diabetes become mild.

    The study concludes[3] that it helps control fluctuations and prevents blood sugar levels from rising. Also, it might help lower insulin resistance in people suffering from type-2 diabetes.

  3. May Lower Cholesterol

    Talking about cholesterol, LDL or bad cholesterol is the heart’s biggest enemy. It makes you prone to heart diseases and deteriorating health.

    Luckily, glucomannan might lower LDL levels along with sugar levels too. Both situations are sure to keep your heart in better condition.

    The study[4] showed that consumption of glucomannan helped in lowering the LDL and non-HDL cholesterol in candidates which in turn, reduced the risk of cardiovascular diseases.

  4. Prevent acne

    Acne might sound like a small problem but they are not. Terrible pain, marks, and itchiness can downgrade healthy skin. One major cause of such acne is bacteria.

    Although glucomannan promotes the growth of probiotic microorganisms, it inhibits the growth of unwanted[5] ones.

    Some of them are E. Coli, propionibacterium, and clostridium perfringens. Therefore, the growth of acne caused by these bacteria might be hindered by glucomannan.

    Therefore, it may be your skincare companion.

  5. May relieve constipation

    Fibers are always great for the gut and it is said that fiber intake is crucial for digestion and bowel movement. The daily requirement for an adult is about 25-30 mg.

    Out of which, about 8 grams should be soluble fiber. Therefore, glucomannan might be a healthy alternative[6] for the same.

    Except for absorbing water and regulating bowel movement, it helps in one more way. It promotes the growth of healthy bacteria, namely, lactobacilli and bifidobacteria.

    Thereby, it may relieve constipation in adults and children, according to this research[7].

  6. Improving hyperthyroidism

    Hyperthyroidism is characterized by overactive thyroid hormones. Combating these high levels of hormones might be possible using glucomannan.

    Some studies involving placebo powder and glucomannan were given. Both Glucomannan and placebo powder were accompanied by methimazole and propranolol.

    The results[8] depicted that glucomannan was a safe and better treatment. It was most effective during the initial stages of treatment.

There is a lack of evidence regarding some health benefits of glucomannan. However, anecdotal accounts suggest the following benefits.

  • It might help reduce[9] insulin resistance in females suffering from PCOS.
  • It is possibly helpful in the treatment[10] of dumping syndrome and postprandial hypoglycemia.

In dumping syndrome, food doesn’t stay in the stomach for long. It moves quickly to the bowel and leaves the digestion.

Glucomannan works exactly the opposite to it. Hence it might prevent or help to some extent in cases of dumping syndrome.

Glucomannan Side Effects

Overall glucomannan is considered a safe supplement to be consumed orally. However, there are chances you might experience[11] some mild side effects. These can be-

  • Nausea
  • Bloating
  • Diarrhea
  • Flatulence
  • Soft stools

It might pose a choking hazard. Cases are not frequent but it is possible. Since glucomannan expands up to 50 times its weight on absorbing water, it can block the esophagus.

It might interact with diabetes meditations like sulfonylurea. There are chances that your blood sugar levels drop too low as a result.

Similarly, it can lower thyroid hormones. Pregnant and breastfeeding ladies should refrain from taking glucomannan.

Glucomannan Dosage

Normally you should not take more than 9 grams a day. The doses should be evenly distributed 3-4 times across the day.

As it expands too much after water absorption, low doses of glucomannan are advised in contrast with other dietary fibers.

The dosage varies according[12] to the use. For example, for diabetes, 3.6-8 grams of glucomannan divided into even doses is suitable.

For digestion purposes, 4.5 grams is apt. If you are consuming it for weight loss, take 1 gram thrice a day. It is also advisable to consume it 15 minutes to 1 hour before meals.

Tablets are available in a range of 500-2000 mg. One should also note that powder is safer than tablets.

Moreover, glucomannan should be washed with a glass of water or two before intake.

Medicines, especially those for diabetes, should be taken 1 hour before or 4 hours after glucomannan consumption.

It is always better to consult your doctor first and then start its use.


Glucomannan is a natural fiber. It is soluble in water. The main source of glucomannan is konjac. It has numerous benefits.

Shirataki noodles, bread, and glucomannan flour might be a healthier alternative. It has very few calories and might satisfy your hunger better.

Although it is a great supplement, it has certain shortcomings. For example, it might cause side effects when not taken properly.

11 References/Sources

Working4Health prefers using primary and verified references. We have strict sourcing guidelines, and our primary references include peer-reviewed research and academic and medical institution studies.

  1. Ramya Devi Devaraj, Chagam Koteswara Reddy, Baojun Xu Health-promoting effects of konjac glucomannan and its practical applications: A critical review Int J Biol Macromol. 2019 Apr 1;126:273-281. doi: 10.1016/j.ijbiomac.2018.12.203. Epub 2018 Dec 23. Available from: https://pubmed.ncbi.nlm.nih.gov/30586587/
  2. Joyce K. Keithley, Barbara Swanson, Susan L. Mikolaitis, et al. Safety and Efficacy of Glucomannan for Weight Loss in Overweight and Moderately Obese Adults J Obes. 2013; 2013: 610908.Published online 2013 Dec 30. doi: 10.1155/2013/610908
  3. V Vuksan, D J Jenkins, P Spadafora, et al. Konjac-mannan (glucomannan) improves glycemia and other associated risk factors for coronary heart disease in type 2 diabetes. A randomized controlled metabolic trial Diabetes Care. 1999 Jun;22(6):913-9. doi: 10.2337/diacare.22.6.913. Available from: https://pubmed.ncbi.nlm.nih.gov/10372241/
  4. Hoang Vi Thanh Ho, Elena Jovanovski, Andreea Zurbau, et al. A systematic review and meta-analysis of randomized controlled trials of the effect of konjac glucomannan, a viscous soluble fiber, on LDL cholesterol and the new lipid targets non-HDL cholesterol and apolipoprotein B Am J Clin Nutr. 2017 May;105(5):1239-1247. doi: 10.3945/ajcn.116.142158. Epub 2017 Mar 29. Available from: https://pubmed.ncbi.nlm.nih.gov/28356275/
  5. F H Al-Ghazzewi, R F Tester Effect of konjac glucomannan hydrolysates and probiotics on the growth of the skin bacterium Propionibacterium acnes in vitro Int J Cosmet Sci. 2010 Apr;32(2):139-42. doi: 10.1111/j.1468-2494.2009.00555.x. Epub 2009 Oct 10. Available from: https://pubmed.ncbi.nlm.nih.gov/19818083/
  6. Youyou Lu, Junxue Zhang, Zhe Zhang, et al. Konjac glucomannan with probiotics acts as a combination laxative to relieve constipation in mice by increasing short-chain fatty acid metabolism and 5-hydroxytryptamine hormone release Nutrition. 2021 Apr;84:111112. doi: 10.1016/j.nut.2020.111112. Epub 2020 Dec 13. Available from: https://pubmed.ncbi.nlm.nih.gov/33454530/
  7. Hsiao-Ling Chen, Han-Chung Cheng, Yann-Jiu Liu, et al. Konjac acts as a natural laxative by increasing stool bulk and improving colonic ecology in healthy adults Nutrition. 2006 Nov-Dec;22(11-12):1112-9. doi: 10.1016/j.nut.2006.08.009. Epub 2006 Oct 4. Available from: https://pubmed.ncbi.nlm.nih.gov/17027233/
  8. Adil Dogan Azezli, Taner Bayraktaroglu, Yusuf Orhan The use of konjac glucomannan to lower serum thyroid hormones in hyperthyroidism J Am Coll Nutr. 2007 Dec;26(6):663-8. doi: 10.1080/07315724.2007.10719645. Available from: https://pubmed.ncbi.nlm.nih.gov/18187431/
  9. V De Leo, C Tosti, V Cappelli, et al. [Combination inositol and glucomannan in PCOS patients] Minerva Ginecol. 2014 Dec;66(6):527-33. Available from: https://pubmed.ncbi.nlm.nih.gov/25373012/
  10. W P Hopman, P G Houben, P A Speth, et al. Glucomannan prevents postprandial hypoglycaemia in patients with previous gastric surgery Gut. 1988 Jul;29(7):930-4. doi: 10.1136/gut.29.7.930. Available from: https://pubmed.ncbi.nlm.nih.gov/2840365/
  11. Luigi Barrea, Barbara Altieri, Barbara Polese, et al. Nutritionist and obesity: brief overview on efficacy, safety, and drug interactions of the main weight-loss dietary supplements Int J Obes Suppl. 2019 Apr; 9(1): 32–49.Published online 2019 Apr 12. doi: 10.1038/s41367-019-0007-3

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