Glucomannan explained: what it is and side effects
Glucomannan is a water-soluble fiber from the root of the konjac plant that becomes very thick. The NIH says it may help you feel full and slow stomach emptying by absorbing water in your digestive tract. Two products we reviewed list glucomannan, and one prints its amount: 50 mg per serving.
- Amounts the NIH names
- Powder or capsule forms seem safe at amounts up to 15.1 g a day for several weeks.
- In the products we reviewed
- 2, 1 print the amount
What glucomannan is
- Glucomannan comes from the root of the konjac plant.3
- Glucomannan is a water-soluble fiber that becomes very thick.1
- Glucomannan can absorb up to 50 times its weight in water.2
- Glucomannan may help you feel full and slow stomach emptying by absorbing water in your digestive tract.2
- Glucomannan comes in powder and capsule forms.3
- Glucomannan is not absorbed into the body and does not reach breast milk.1
How much glucomannan each product gives
NIH: 15,100 mg per dose
Amount not printed: the dashed line shows the most it can be, the whole blend
Before you take it
If you take medicines
Side effects
- Glucomannan can cause burping, bloating, loose stools, gas, diarrhea, constipation, and belly discomfort.2
- Glucomannan tablets might block the tube that carries food from your mouth to your stomach.2
Ask a doctor first
- Be cautious when taking glucomannan tablets.2
- Little is known about the long-term safety of glucomannan.2
- If you are breastfeeding, consult your healthcare provider for advice specific to your situation.1
These statements have not been evaluated by the FDA. A supplement is not a medicine.
The 2 products we reviewed that list glucomannan
| Product | Form and serving | Glucomannan per serving | Our score | Price a bottle | Buy |
|---|---|---|---|---|---|
 VitaliSlim#4 in weight loss support | Capsules1 capsule | 50 mg | 9.2 | $49 | Check price |
 LipoSlend#8 in weight loss support | Liquid drops1 ml | Not printedIn a 500 mg proprietary blend | 8.8 | $49 | Check price |
Questions people ask
What is glucomannan?
Glucomannan is a water-soluble fiber from the root of the konjac plant. It becomes very thick and can absorb up to 50 times its weight in water.
What does glucomannan fiber do in the body?
Glucomannan may help you feel full and slow stomach emptying by absorbing water in your digestive tract, according to the NIH. It is not absorbed into the body.
How much glucomannan can I take per day?
The NIH says glucomannan powder or capsule forms seem safe at amounts up to 15.1 g a day for several weeks. Little is known about its long-term safety, so ask a clinician before starting.
What are the side effects of glucomannan?
Glucomannan can cause burping, bloating, loose stools, gas, diarrhea, constipation, and belly discomfort.
Is glucomannan safe?
Glucomannan powder and capsule forms seem safe at amounts up to 15.1 g a day for several weeks, according to the NIH. Tablets might block the tube that carries food from your mouth to your stomach. Be cautious with tablets and ask a clinician before starting.
Which supplements we reviewed contain glucomannan?
VitaliSlim and LipoSlend both list glucomannan. VitaliSlim prints 50 mg per serving of 1 capsule. LipoSlend lists it inside a 500 mg proprietary blend per 1 ml serving, without printing its separate amount.
Sources
The products, amounts and prices come from each product's label and checkout, as its review shows them. AI drafts our pages from listed sources, figures are checked against them, and we have not tried the products.
- 1NIH LactMed, Glucomannanncbi.nlm.nih.gov/bookschecked
- 2NIH Office of Dietary Supplements, WeightLoss HealthProfessionalods.od.nih.gov/factsheetschecked
- 3NIH Office of Dietary Supplements, WeightLoss Consumerods.od.nih.gov/factsheetschecked