Pure Glucomannan (Konjac Root Fibre)

Metabolism & weight management

Function & benefits

A highly soluble fibre from konjac root that absorbs water and swells into a gel that fills the stomach and slows emptying; glucomannan contributes to weight loss in the context of an energy-restricted diet (EFSA-authorised claim at 3 g a day).

Dosage & how to use

Recommended dose	1 g three times daily (3 g in total, per EFSA)
Best time to take	15–30 minutes before main meals with two large glasses of water (500 ml)
Frequency	3 times daily

Best forms to choose

Capsules or sachets of 100% pure glucomannan, swallowed or dissolved in water straight away before it gels.

Important warnings

Choking warning (EFSA): never swallow it without plenty of water, as it can swell in the oesophagus and block the throat, especially in people with swallowing difficulties

Do not take it right before bed

May cause bloating and gas at first

Drug interactions

The gel hinders the absorption of oral medicines; take medicines at least two hours before it or four hours after it (especially diabetes and blood pressure drugs and birth control pills).

View in the supplements guide

Related supplements

Scientific references

EFSA Journal 2010;8(10):1798 (glucomannan and reduction of body weight)
Sood N et al. Am J Clin Nutr 2008 (systematic review) — PMID: 18842808

📚 Published sources and research: European Food Safety Authority (EFSA) • National Institutes of Health (NIH - ODS) • PubMed / Cochrane databases

Content last updated: 17 October 2026 · Based on published sources and research (EFSA / NIH / PubMed)

⚖️ Medical disclaimer: The information and data provided here are for health education and nutritional guidance only. They are not a medical diagnosis and never replace a direct consultation with your doctor or pharmacist. Always consult your doctor before starting any supplement, especially during pregnancy or breastfeeding or when taking long-term medication.