Weight Management
Glucomannan (Konjac Fibre)
Also known as: Konjac root extract · Konjac glucomannan · Amorphophallus konjac
The most viscous dietary fibre known. Expands significantly in the stomach, creating profound satiety. One of the few supplements for weight loss with EFSA-approved claims.
Effective Dose
3–4g / day before meals
per clinical evidence
Evidence Level
Moderate
Weight Management
Mechanism
Viscous dietary fibre — gastric expansion, delayed gastric emptying, satiety
primary action
Best For
Appetite suppression
Cholesterol reduction, Blood sugar management
This profile is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications.
What Is Glucomannan (Konjac Fibre)?
Glucomannan is a highly viscous soluble fibre from the konjac root. It absorbs up to 50× its weight in water, forming a gel in the stomach that dramatically slows gastric emptying and nutrient absorption. It has received approval from EFSA (European Food Safety Authority) for weight management claims — a rare distinction among food supplements.
How It Works: The Science
In the stomach, glucomannan forms a highly viscous gel (viscosity ~40,000 cP) that physically delays gastric emptying, slows glucose absorption, entraps bile acids (reducing cholesterol reabsorption), and stimulates satiety hormones (GLP-1, PYY) via the ileal brake mechanism. It is fermented by colonic bacteria into short-chain fatty acids (prebiotic effect).
Primary Mechanism
Viscous dietary fibre — gastric expansion, delayed gastric emptying, satiety
Evidence-Based Benefits
Dosage Guide
Effective Dose
3–4g / day before meals
3–4g/day split into doses taken 30–45 minutes before meals with at least 250ml water. Must be taken with substantial fluid — swallowing glucomannan tablets without water risks oesophageal obstruction. Capsule or powder form preferred.
Safety Profile & Side Effects
Critical: must be taken with large amounts of water. Oesophageal obstruction has been reported with rapid-expanding tablets. GI bloating and flatulence common initially. May reduce absorption of oral medications — take separately.
Who Should (and Shouldn't) Take It
Those struggling with appetite control in a caloric deficit. Very effective for post-meal satiety and blood sugar management. Also useful for high cholesterol alongside dietary changes.
Frequently Asked Questions
Related Ingredients
Medical Disclaimer
Ingredient profiles are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications. Full disclaimer →