When to take it
15–30 minutes before main meals with 1–2 glasses of water.
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DigestionModerate evidence
Glucomannan
Also known as: konjac, konjac fibre, Amorphophallus konjac
Glucomannan is a soluble fibre from the konjac tuber that can bind large amounts of water and forms a bulky gel in the stomach. This promotes fullness and reduces cholesterol absorption.
What it is used for
- Weight loss on an energy-restricted diet – moderate evidence (EFSA-approved claim at 3 g a day in three doses before meals)
- Maintenance of normal cholesterol – moderate evidence (EFSA, 4 g a day)
- Bowel support – moderate evidence
Forms and how they differ
powder
cheapest, mix with water and drink at once
capsules
convenient, always take with 1–2 glasses of water
glucomannan + chromium
chromium adds a blood-glucose claim but does not boost weight loss
konjac noodles
a very low-energy food
Pairs well with
An energy-restricted diet, enough protein and exercise.
Do not combine / separate
Take medicines and other supplements at least 2 hours apart; never take it just before bedtime.
Watch out for
Not suitable with swallowing difficulties or narrowing of the oesophagus or bowel (risk of blockage). With diabetes treated with medicines it may lower blood glucose. In pregnancy, kidney or liver disease and when taking medicines, consult your doctor.
Safety
No EFSA tolerable upper level; do not exceed the label dose and always take it with enough water.
Practical tip
Never swallow a capsule dry – the gel can swell in the oesophagus.
Products containing Glucomannan 4
Glucomannankonjac root
Glucomannan + chromium+ chromium
Glucomannan konjackonjac
Glucomannan konjackonjac
How to read the evidence rating
Strong evidenceModerate evidenceWeak evidenceNo evidence
Strong = several good human studies or official recommendations; moderate = promising but smaller studies; weak = few studies or mixed results; no evidence = claims not confirmed.
Combination check
Select the supplements you take and, if relevant, your medicines. We show what interferes, what needs a time gap and what to watch out for.
Check Glucomannan with othersWhich supplements do you actually need?
Fénix Methode picks them from your blood results and schedules when to take what – no needless purchases.
From the same group
Acacia fibreWeak evidenceActivated charcoalModerate evidenceAloe veraWeak evidenceApple fibreModerate evidenceArtichokeWeak evidenceBetaine HClWeak evidence
Important notice
This information is educational and does not replace advice from a doctor or pharmacist. We do not give medicine dosages. Supplements are no substitute for a varied diet; if pregnant, breastfeeding, ill or on medication, consult a doctor first.