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Fiber

Glucomannan

Glucomannan is a soluble dietary fiber from the root of the konjac plant (Amorphophallus konjac).

CardiovascularWeight ManagementGut Health

What it is studied for

The strongest rated effects first. Bars show the size of the effect, the letter grades the evidence, and each rating lists the studies behind it.

Cholesterol balanceCardiovascularStrongA3 studies
ConstipationStrongA3 studies
Blood sugarWeight ManagementModerateA3 studies
Gut healthModerateBNo linked study
Weight lossWeight ManagementSmallBNo linked study
Bloating & gas reliefGut HealthSmallCNo linked study
Every rating with its studiesGrouped by health goal, with the publications behind each rating

What does glucomannan do?

Glucomannan is a soluble fiber from konjac root. It absorbs water in the digestive tract; greater fullness and slower stomach emptying are proposed explanations for its use in weight-management research. Those mechanisms do not guarantee weight loss. 1

Key studies

The most recent publications linked to Glucomannan's ratings.

Does glucomannan supplementation exert profitable effects on serum lipid profile in adults? A systematic review and meta-analysis.2024Effects of Glucomannan Supplementation on Type II Diabetes Mellitus in Humans: A Meta-Analysis2023The effect of Glucomannan on fasting and postprandial blood glucose in adults: a systematic review and meta-analysis of randomized controlled trials2022The effect of glucomannan on pregnancy constipation2018A systematic review and meta-analysis of randomized controlled trials of the effect of konjac glucomannan, a viscous soluble fiber, on LDL cholesterol and the new lipid targets non-HDL cholesterol and apolipoprotein B.2017
All 8 studiesEvery publication linked to Glucomannan

Why people take it

Weight Management23.9%
Gut Health21.3%
Essential Health14.2%
Detox10.3%
Energy9.7%
Cardiovascular8.4%

SuppCo community snapshot, 2026-09-28. Reasons for use are not evidence that it works.

Questions people ask

Does glucomannan lower LDL cholesterol?

The pooled trials found a reduction, though their size and duration were limited. They did not establish prevention of cardiovascular events. 2

Is it a reliable weight-loss supplement?

Results vary. The favorable EFSA assessment was tied to a calorie-restricted diet and specific dosing conditions. 1 3

Can it help constipation?

Health Canada recognizes its use as a bulk-forming laxative, which increases stool bulk and water content. 4

Sources