What is Konjac?

What are the benefits of konjac?

Konjac is a plant that is used to make high-fiber dietary supplements, jellies, and flour. It is used traditionally in both Japanese cuisine and Chinese medicine. But does konjac have any proven health benefits?

The proper name for the konjac plant is Amorphophallus, but it is also sometimes called konjaku, elephant yam, devil’s tongue, snake palm, and voodoo lily.

This article explores the potential health benefits of konjac as supported by scientific evidence. It also looks at how to use konjac and whether there are any risks to consider before taking it.

What is konjac?

Konjac root
Konjac is traditionally used in Japanese cuisine and Chinese medicine.

The konjac plant has a starchy root called a corm, which is high in a dietary fiber called glucomannan. This is the part of the plant that is used as a dietary supplement and to make high-fiber flour and jellies.

A range of different products can be made from the konjac corm, including:

  • Konjac flour: This is made by grinding down dry konjac corms to make flour that can be used to make noodles.
  • Konjac jelly: After further processing, konjac flour can be used to make a jelly or gum. This can be used instead of gelatin to thicken food.
  • Konjac soluble fiber: When konjac jelly is purified further, it can be made into a soluble fiber that is used as a dietary supplement.

Six health benefits of konjac

Konjac has a number of health potential benefits that are explored below. Many of these benefits relate to the high content of glucomannan, the soluble dietary fiber that is in the konjac plant.

1. Diabetes management

Research has shown that consuming a mix of glucomannan and American ginseng indicated a moderate improvement in type 2 diabetes management.

2015 review also noted glucomannan made people with diabetes less likely to eat foods that could increase their blood sugar levels. This is because it made them feel fuller for longer.

2. Weight loss

Glucomannan made from konjac may be beneficial for people who are looking to lose weight.

2005 study found that the soluble dietary fiber supplement helped people who were overweight to reduce their body weight. The people took the supplement as part of a balanced, calorie-controlled diet. This type of fiber helps a person feel full longer by slowing gastric emptying.

Researchers compared the effects of the glucomannan supplement with a guar gum supplement. They found that the glucomannan supplement increased weight loss whereas the guar gum supplement did not.

There are numerous studies that show the health benefits of higher fiber diets, including using konjac, for weight loss.

3. Cholesterol

hyperlipiedmia cholesterol
Glucomannan may have a beneficial effect on cholesterol levels.

Having high cholesterol means that people are more likely to experience heart disease or have a stroke. Water-soluble fibers are recommended to aid in cholesterol and weight management.

Glucomannan supplements may help people to keep their cholesterol levels in check. A 2008 study found that glucomannan had a beneficial effect on overall cholesterol levels.

A further study in 2017 looked at what dose of glucomannan was needed to improve cholesterol levels. Researchers found 3 grams per day to be a beneficial dose.

4. Constipation

Taking a glucomannan supplement may help to regulate a person’s bowel movements and prevent them from becoming constipated.

2006 study found that a modest dose glucomannan improved bowel movements in adults by 30 percent. Researchers also found the soluble dietary fiber supplement helped to improve gut health in people experiencing constipation.

A recent review from 2017 found that taking glucomannan improved the frequency of bowel movements in children with constipation.

However, researchers noted that taking glucomannan did not always improve stool consistency or the overall success rate of treatment.

5. Healthy skin

Glucomannan may also help people looking to improve the health of their skin.

2013 study found that glucomannan may be beneficial as a topical therapy for acne and that it improves overall skin health.

6. Wound healing

As well as supporting skin health, glucomannan may also help the body to heal wounds more quickly.

2015 study in mice found that glucomannan supplements may encourage wound healing because of the way they support the immune system. However, more research is needed to conclude that glucomannan is effective for wound healing in humans.

How to use konjac

woman in supermarket shopping for vitamins and supplements and checking the labels of different brands
Konjac may be used in glucomannan dietary supplements.

Glucomannan dietary supplements made from konjac are available in most health food stores. The precise dose of konjac a person should take depends on the reason they are taking it, as well as their age and overall health.

The United States Food & Drug Administration (FDA) does not regulate konjac supplements, so it is essential to purchase them from a reputable retailer.

Powder made from konjac corms is sometimes used as an alternative to seafood in vegan food.

Konjac is also used to make facial sponges for people looking to take advantage of the health benefits it has for the skin.

Other konjac products include:

  • fruit jelly
  • flour
  • noodles

Risks and considerations

When eaten as a fruit jelly, konjac may pose a choking risk, especially in children. This is because it absorbs a lot of water and does not dissolve readily. It is important to chew konjac jelly thoroughly to make sure it can be swallowed easily.

Konjac supplements can have an impact on blood sugar levels, so people with diabetes should talk to a doctor before using them.

Due to the way konjac affects the gut and reduces constipation, some people may experience diarrhea when they take konjac supplements.


Konjac products have a number of health benefits. They may help keep blood sugar and cholesterol levels low, improve skin and gut health, help heal wounds, and promote weight loss.

As with all unregulated dietary supplements, it is best to speak to a doctor before taking konjac. A person should also discuss konjac with a doctor before giving it to a child for constipation or other problems. Konjac should always be consumed with water to avoid a choking hazard.