Glucomannan
Research reviewed: 2005–2018
Glucomannan (Konjac glucomannan) is a dietary supplement with 9 published peer-reviewed studies involving 1,129 participants, researched for Weight Management, Blood Glucose Control, Cholesterol Management and 2 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Weight Management
ModerateBlood Glucose Control
ModerateCholesterol Management
ModerateGut Health & Satiety
ModerateClinical trials
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Weight Management
Quantify glucomannan effect on body weight in overweight adults
Study Type
Meta-Analysis
Purpose
Quantify glucomannan effect on body weight in overweight adults
Dose
2–4 g/day
Participants
293
Duration
4–12 weeks
Results
Glucomannan reduced body weight by −0.79 kg vs placebo; effect modest but significant; greatest with caloric restriction
How They Measured It
Pooled body weight, BMI outcomes across RCTs
Update evidence on glucomannan for body weight management
Study Type
Systematic Review
Purpose
Update evidence on glucomannan for body weight management
Dose
3 g/day
Participants
420
Duration
4–16 weeks
Results
Significant weight reduction (mean −0.84 kg); greater effects with calorie restriction; no serious adverse events
How They Measured It
PRISMA systematic review with meta-analysis
Blood Glucose Control
Test glucomannan on blood glucose in type 2 diabetes
Study Type
Randomised Controlled Trial
Purpose
Test glucomannan on blood glucose in type 2 diabetes
Dose
3.6 g/day
Participants
110
Duration
12 weeks
Results
Significant reductions in fasting glucose (−9.4%) and HbA1c (−0.4%); postprandial glucose peak reduced by 15%
How They Measured It
Fasting glucose, postprandial glucose, HbA1c
Assess glucomannan on insulin sensitivity and glucose control
Study Type
Randomised Controlled Trial
Purpose
Assess glucomannan on insulin sensitivity and glucose control
Dose
4 g/day
Participants
55
Duration
8 weeks
Results
HOMA-IR improved by 23%; insulin sensitivity enhanced; insulin response to glucose load blunted
How They Measured It
HOMA-IR, insulin, glucose tolerance test
Cholesterol Management
Evaluate glucomannan on blood lipids in hypercholesterolaemia
Study Type
Randomised Controlled Trial
Purpose
Evaluate glucomannan on blood lipids in hypercholesterolaemia
Dose
3 g/day
Participants
88
Duration
8 weeks
Results
LDL reduced by 16%; total cholesterol reduced by 10%; triglycerides reduced by 11%; HDL unchanged
How They Measured It
Total cholesterol, LDL, HDL, triglycerides
Gut Health & Satiety
Assess glucomannan effect on satiety hormones and appetite
Study Type
Randomised Controlled Trial
Purpose
Assess glucomannan effect on satiety hormones and appetite
Dose
4 g before each meal
Participants
40
Duration
4 weeks
Results
Significant increase in postprandial GLP-1 and PYY; reduced ghrelin; appetite VAS scores significantly reduced; energy intake decreased
How They Measured It
GLP-1, PYY, ghrelin, appetite VAS scales
Evaluate glucomannan as prebiotic on gut microbiome
Study Type
Randomised Controlled Trial
Purpose
Evaluate glucomannan as prebiotic on gut microbiome
Dose
4 g/day
Participants
45
Duration
12 weeks
Results
Significant increase in Bifidobacterium and Lactobacillus; increased butyrate; improved stool consistency and frequency
How They Measured It
16S rRNA sequencing, SCFA production, stool frequency
Assess glucomannan on gut health and bowel function
Study Type
Randomised Controlled Trial
Purpose
Assess glucomannan on gut health and bowel function
Dose
3 g/day
Participants
78
Duration
12 weeks
Results
Improved stool consistency and frequency; reduced constipation; GSRS total score improved; no adverse GI events
How They Measured It
Bristol Stool Scale, transit time, GSRS questionnaire
Clinical trials
To assess the effects of konjac glucomannan (KGM) on gastrointestinal symptoms and gut microbiota in elite male athletes with functional constipation.
Study Type
Double-blind, randomized controlled trial
Purpose
To assess the effects of konjac glucomannan (KGM) on gastrointestinal symptoms and gut microbiota in elite male athletes with functional constipation.
Dose
KGM supplementation for 8 weeks
Participants
Elite male Taekwondo athletes with functional constipation (Rome IV criteria)
Duration
8 weeks
Results
KGM significantly improved PAC-SYM, PAC-QoL, bowel movement frequency, and BFI scores. Increased Prevotella, Lactobacillus, Bifidobacterium; decreased Alistipes and Desulfovibrio.
How They Measured It
PAC-SYM, PAC-QoL, bowel movement frequency, Bristol Stool Scale, Bowel Function Index; gut microbiota (16S rRNA)
Frequently Asked Questions
Common questions about Glucomannan research
There are currently 9 peer-reviewed studies on Glucomannan (Konjac glucomannan), involving 1,129 total participants. Research covers Weight Management, Blood Glucose Control, Cholesterol Management and 1 more areas. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (9 human studies), and reported outcomes.
Glucomannan has been researched for: Weight Management, Blood Glucose Control, Cholesterol Management, Gut Health. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 9 out of 9 studies are human trials. Human trials carry more weight in our evidence scoring system.
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