Benefits of Glucomannan: Does It Promote Weight Loss? (Overview, Uses, and Side Effects)

Burn excess fat, lose weight, and cure constipation with this remarkable supplement.

Glucomannan has a long history of use in Chinese traditional medicine. The Chinese and Japanese have been using this herbal remedy for several purposes, and its efficacy for these uses is a pretty profound story.

Today, this fiber has also found its way to other parts of the world, where it is now used to treat various illnesses. It is now available as a dietary supplement and used by obese and overweight individuals.

Interestingly, there is empirical evidence that it supports the efficacy of it as a weight-loss supplement. Here, we’ll discuss these scientific studies, plus their uses and other glucomannan benefits.


What is Glucomannan (Konjac)?

Glucomannan is an herbal supplement obtained from the root of the elephant yam, also called the Konjac plant or Amorphophallus konjac.

The Konjac plant naturally grows in Asia and is widely cultivated. The Konjac root is rich in water-soluble fibers, which explains why it is traditionally used to remedy constipation.

The glucomannan powder is obtained from the root of the Konjac, but interestingly, you don’t have to visit any Asian country to get it anymore.

It is now available in drinks and added food products like Konjac flour and pasta. Its functions in these products vary, one of which is to aid digestion.

Konjac Glucomannan is also the active ingredient in shirataki noodles. Therefore, besides being used as a dietary supplement, many companies also use glucomannan as a food additive.

It serves as an emulsifier and a thickening agent in some products. Its E-number is E425-ii. It performs these functions effectively because of its unique property to absorb so much liquid easily.

Its absorbing power is so significant that even a tiny drop in a glass of water can turn the water into a gel.

These incredible features are why it is believed to be one of the reliable supplements in weight reduction.

How Does Glucomannan Work For Weight Loss?

Glucomannan is an effective supplement for weight loss, and several studies prove this.

One such research was conducted on 176 healthy but overweight people. People during the study were subjected to a calorie-restricted diet.

They were divided into two different groups.

The first group was given a placebo. The second group, on the other hand, was assigned Konjac Glucomannan supplements (1).

The Glucomannan group was further divided into three groups, each given a different powder and tablets form with different dosages.

They took the substance continuously for weeks. At the end of the fifth week, the result shows that all the study participants in the Glucomannan group lost more weight than the placebo group.

The effect is highly significant, such that one can conclude based on that study that glucomannan can aid weight loss in overweight and obese people.

Further studies back the result provided by this study. However, like other efficient weight loss methods, glucomannan’s effect on weight loss can be even better if you combine it with a weight-reducing diet.

But how does it work? Well, the weight loss efficiency of glucomannan is not magic. There are scientific explanations of how it works. Being a water-soluble fiber, it can help to drop weight because of the following reasons:

It Is Low In Calories

Meals high in calories can increase the body fat contents in your body, thereby improving your weight.

Glucomannan is low in calories. If a substance is low caloric, it is doesn’t add up to your weight.

Reduce The Rate of Digestion

If you have an increased digestion rate, your satiety will increase, and you’ll eat more. The more you eat, the more fats your body will likely store.

Konjac Glucomannan helps to reduce the rate of digestion, thus, reducing your satiety.

Once your craving to eat drops, you will eat less, allowing your body more time to digest and absorb the nutrients in the foods you eat. If you don’t eat much, your body won’t store more fats (2).

As a Fiber Supplement, It Occupies Space in Stomach

Glucomannan occupies more space in your stomach, promoting your feeling of fullness.

That way, you won’t feel the need to eat more. As a consequence of not overeating, you’ll eventually lose weight.

Reduce Protein and Fat Absorption

Glucomannan powder, being a soluble fiber, reduces the rate at which your body absorbs fats. When your body does not absorb the fats, they’ll pass out as feces.

Hence, with such a reduction in the rate of fat absorption, your weight gain rate will also decrease (3).

What Are The Glucomannan Benefits?

Glucomannan has several health benefits, some with scientific evidence and some with no scientific evidence yet.

Below are some health benefits backed with scientific research:

Promote Weight Loss

Several studies confirm the efficiency of these fiber supplements in weight loss and body composition changes.

In 2005, a study was published in Alternative Therapies in Health and Medicine about the efficacy of glucomannan on weight loss.

The study reveals that taking between 2 grams and 4 grams of this supplement daily can promote weight loss in overweight and obese adults (4).

The outcome is attributed to the reduced satiety effect of glucomannan supplementation, and the addition of guar gum did not make an extra decline of weight.

The exceptionally dense nature of glucomannan, when mixed with water, increases your feeling of fullness. When you take this powder, it absorbs the water in your stomach to become a highly viscous Konjac jelly that fills up the gut.

This effect makes you feel full for an extended period, tricking your mind that you have enough in your stomach already. This is a significant way it helps to reduce the feeling of satiety.

With reduced satiety comes a decreased calorie intake, and with a reduced-calorie input comes weight loss.

Reduce Blood Cholesterol

Having high cholesterol levels can increase a person’s chance of developing heart disease, including high blood pressure.

However, studies have shown that this soluble dietary fiber can help to reduce blood cholesterol levels. We can back this claim with a 2008 study published in the American Journal of Clinical Nutrition (5).

The study reviews 14 different clinical trials. It shows that glucomannan supplements can reduce low-density lipoprotein (LDL) cholesterol and total cholesterol in the body.

The LDL is what scientists call the “bad cholesterol.” If a person has a high LDL, the person is prone to have cardiovascular diseases. Hence, LDL is not healthy cholesterol.

It is this same cholesterol that glucomannan reduces. However, there’s another cholesterol, called the high-density lipoprotein (HDL), also known as the good cholesterol. The study shows that the supplement doesn’t affect HDL.

Help With Constipation

Soluble fibers are known for their ability to help maintain or improve digestion and nutrition. When you constipate, it means your digestion didn’t go well.

Constipation occurs when there’s a lesser than required water absorption in your digestive tract during digestion. Glucomannan is a soluble fiber powder; thus, it can help with this.

It aids the rate of water absorption in your intestine, allowing for easy digestion. Health providers often recommend that people take about 25 to 30 grams of dietary fiber per day.

If you have chronic constipation, you can take this supplement to get rid of it. This claim is proven by several studies, one of which is the 2018 study posted in the Journal of Family Medicine and Primary Care.

This study shows that glucomannan is more efficient as an alternative medicine to relieve constipation than magnesium hydroxide (6).

It is a Natural Prebiotic

Glucomannan supplements have been shown to have a prebiotic property. It is, therefore, suitable for your digestive system.

It helps to feed the friendly bacteria in the intestine. Studies confirm that feeding one’s Gut Bacteria has a relationship with altering body weight and provides several health benefits (7).

Thus, if you need a safe natural prebiotic, taking glucomannan is not a bad option.

Improve Diabetes Management

People have diabetes because there is a higher glucose level than insulin required to convert the glucose to glycogen.

When the glucose continues to pile up and remain unused or not converted, it may eventually result in high blood sugar levels, otherwise called diabetes.

Now, imagine tablets that help to reduce these high blood sugar levels in the body. Will that supplement help to improve diabetes management? The answer is evident already.

Glucomannan helps to increase the sense of fullness, thereby reducing the quantity of food you eat. With such reduction, there’ll be lesser food to convert to glucose.

When there’s lesser glucose, there’ll be lesser blood sugar, thereby improving diabetes management.

A 2015 review shows that taking this supplement helps people with diabetes eat lesser foods to lower their sugar level (8).

How To Take Glucomannan To Lose Weight

For a better result, you must take glucomannan at the proper dosage, and it must be taken before a meal.

The recommended time difference between when you take the supplement and when you take your meal is between 15 min to 1 hour.

For better efficiency, you should take glucomannan at least 15 minutes before eating or not more than 1 hour before eating (9).

It is available as powders, tablets, and capsules, any of which you can choose to use. It also comes in different sizes and concentrations. You can find it as low as 500 mg and as high as 2000 mg.

The suitable dosage to use depends on the aims of use. However, for weight loss, 3000 mg or 3 g per day is considered safe and sufficient. This should be divided into three doses, such that you take 1 gram each time three times a day (10).

It would be best to take the supplement doses, whether as a powder or other forms, with about 1 to 2 glasses of water for better absorption.

When glucomannan powder is mixed with water, the supplement can expand and absorb up to 50 times its weight. This is why the recommended dosage of glucomannan is lesser than other fiber supplements.

How Long Does It Take To Work

This supplement begins to work almost immediately after it lands in your stomach.

However, it would be best to don’t interpret this as losing weight immediately after taking it. Instead, the effects of glucomannan on reducing food craving begin almost immediately after taking it.

It is a continuous process of not eating carelessly that will eventually cause weight loss.

Side Effects of Glucomannan Dietary Supplement

Glucomannan is safe to use. However, like other supplements, it also has some side effects that you may want to look out for.

May Block Esophagus

If it expands before reaching the stomach, it may block the esophagus.

To avoid this, push the supplement down with enough water when you take it.

May Affect The Absorption of Other Medications

Glucomannan can affect the absorption rate of other drugs.

To avoid this, you should take your medications about four hours after taking this supplement or one hour before ingesting it.

It may also cause bloating, flatulence, or diarrhea.


Based on scientific studies, user stories, and available evidence, glucomannan is a safe supplement and safer than taking unknown weight loss pill.

It is an effective weight loss supplement that also helps with constipation, improves diabetes management, and acts as a natural probiotic, among other benefits.

However, to obtain a significant result, you must take the appropriate dosage of the supplement.

If you’re looking for safe and efficient weight loss supplements, this is one you can trust.


How much weight can you lose with glucomannan?

You can lose up to 10 pounds (4.5 Kg) of weight in 5 weeks if you take glucomannan.

This is based on the result obtained from three human studies. However, to get such a significant effect, you should combine this supplement with a healthy diet.

Eating calorie-rich meals when you’re trying to lose weight will not help (11).

You can also engage in a weight loss program. This will help you lose more weight and aid your physical fitness.

Is glucomannan a resistant starch?

Yes! Glucomannan is a resistant starch as it comprises mannose and glucose molecules connected to form long chains.

It is resistant to breakdown and cannot be split into simpler molecules by the salivary or pancreatic enzyme.

How many grams of fiber are in glucomannan?

86 grams of glucomannan contains about 9 grams of digestive fiber.

Can you take glucomannan and psyllium husk together?

Yes! You can combine glucomannan and psyllium husk.

Research shows that this combination can enhance the rate of weight loss.