Glucomannan
A highly viscous soluble fiber from konjac root that expands with water in the stomach to promote fullness and slow digestion.
Also known as konjac fiber, Amorphophallus konjac.
What to know
Weight-loss findings conflict; swallowing safety matters.
Editorial summary reviewed . Literature and label checks below have separate dates.
What the evidence says
NIH ODS reports inconsistent weight-loss results, including reviews finding no significant benefit over placebo.
Marketed as: Sold as a natural appetite suppressant for weight loss. A proposed mechanism or a finding about an ingredient does not establish benefit for every finished product.
What to watch for
Can cause digestive symptoms. Tablets have caused esophageal obstruction; long-term safety is uncertain. Follow the product's fluid instructions.
Literature search counts
Counts · Oct 3, 2026 UTC- RCT-tagged publications
- 77 (RCT-tagged publications)
- Systematic-review publications
- 46 (Systematic-review publications)
- All search matches
- 4,229 (All search matches)
These are search matches, not a count of independent trials or proof of benefit. Publication types overlap. Results may include animal research, articles mentioning several ingredients, or retracted work. Counts do not assess study quality and may change after retrieval.
NIH product-label records
A sample of NIH Dietary Supplement Label Database records. Listing is not FDA approval, proof of effectiveness or confirmation a product is still sold.
- GlucomannanOff marketNOWCapsule
- Glucomannan Pure PowderOff marketNOWPowder
- Glucomannan RootOff market
Glucomannan: common questions
Does Glucomannan work for weight loss?
NIH ODS reports inconsistent weight-loss results, including reviews finding no significant benefit over placebo. It is not a substitute for an FDA-approved GLP-1 medication.
Is Glucomannan a GLP-1 or "natural Ozempic"?
No. Glucomannan is a fiber supplement marketed as "natural GLP-1" support, but it is not a GLP-1 receptor agonist and is not FDA-approved to treat obesity or type 2 diabetes. It does not work the way semaglutide or tirzepatide do. Humanome, an educational atlas we also run, explains how semaglutide acts on the pancreas, stomach and liver.
Is Glucomannan safe?
Can cause digestive symptoms. Tablets have caused esophageal obstruction; long-term safety is uncertain. Follow the product's fluid instructions. Dietary supplements are not reviewed by the FDA for safety and quality the way approved drugs are, so talk with a licensed clinician before starting, especially alongside a prescription medication.