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Gm6.5
Glucomannan Research
Likely helps
74 peer-reviewed studies
What the evidence says
Likely helps
Glucomannan appears to help in 10 of 11 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 1984–2026 with a typical study size of 58 participants.
Based on 74 studies · 9 meta-analyses · 52 RCTs · 8,884 total participants
Confidence
High confidence
What the studies found
10helped1unclear· 63 more without graded effect data
By outcome
Weight managementSatiety and reduced caloric intake · 4-8 weeks
Digestive healthPrebiotic fiber promotes healthy bowel function and microbiome · 1-2 weeks
Likely helps61 studies
Heart & blood pressure
Mostly mechanism / observational3 studies
Therapeutic & clinical
Too few graded studies2 studies
By the numbers
Pulled from 25 studies with measurable effects
Likely real effects
100%
across studies
People studied
8,884
typical study: 58 people
Strongest designs
61
9 pooled, 52 randomised
Showed benefit
91%
10/11 studies
How long studies ran
1–4 weeks
2
1–3 months
1
3+ months
2
Populations Studied
Adults2
Adults with obesity2
Type 2 diabetes mellitus patients2
Adults with overweight or obesity1
Steady research
22 studies in the last 5 years · Latest meta-analysis: 2025
198420052026
1Body weight reductionMeta-Analysisn=6,171 · very large study2023
In plain English: We conducted random-effects network meta-analysis with a Frequentist framework to estimate mean difference [MD] and 95% confidence interval [CI] of the effect of nutraceuticals on weight loss.
Shahinfar H et al. · Pharmacological research (2023)
Noticeable benefit
← WorseNo effectBetter →
We conducted random-effects network meta-analysis with a Frequentist framework to estimate mean difference [MD] and 95% confidence interval [CI] of the effect of nutraceuticals on weight loss.
Supplementations with green tea (MD: -1.25 kg, 95%CI: -1.68, -0.82) and glucomannan (MD: -1.36 kg, 95%CI: -2.17, -0.54) demonstrated small weight loss, also the certainty of evidence was rated low.
Based on our findings, supplementations with nutraceuticals can result in a small weight loss in adults with overweight or obesity.
In plain English: The evidence from available RCTs does not show that glucomannan intake generates statistically significant weight loss.
Onakpoya I et al. · Journal of the American College of Nutrition (2014)
No clear effect
← WorseNo effectBetter →
A meta-analysis (random effect model) of 8 RCTs revealed a nonstatistically significant difference in weight loss between glucomannan and placebo (mean difference [MD]: -0.22 kg; 95% confidence interval [CI], -0.62, 0.19; I(2) = 65%).
The evidence from available RCTs does not show that glucomannan intake generates statistically significant weight loss.
Future trials should be more rigorous and better reported.
10Total cholesterol reductionMeta-Analysisn=531 · large study2008
In plain English: Glucomannan appears to beneficially affect total cholesterol, LDL cholesterol, triglycerides, body weight, and FBG, but not HDL cholesterol or BP.
Sood N et al. · The American journal of clinical nutrition (2008)
Glucomannan appears to beneficially affect total cholesterol, LDL cholesterol, triglycerides, body weight, and FBG, but not HDL cholesterol or BP.
13Weight management and metabolic indicatorsReview2026
In plain English: This review emphasized the need for purpose-driven supplement selection that integrates efficacy, safety, usage context, and evidence level, and the importance of consumers' critical information appraisal capacity, supported by structured information provision and education.
Lee H et al. · Nutrients (2026)
PubMed, MEDLINE, and Google Scholar databases were searched for studies published between 1 January 2020 and 10 October 2025.
Although some studies have reported improvements in weight and metabolic indicators, consistent scientific evidence has not yet been established.
This review emphasized the need for purpose-driven supplement selection that integrates efficacy, safety, usage context, and evidence level, and the importance of consumers' critical information appraisal capacity, supported by structured information provision and education.
16Body weight reductionRCTn=112 · medium study2024
In plain English: Dietary supplementation with glucomannan, inulin, and psyllium effectively promotes weight loss and improves body composition in individuals with obesity, particularly those with specific genetic polymorphisms.
Pokushalov E et al. · Nutrients (2024)
Barely noticeable benefit
← WorseNo effectBetter →
Likely real
The experimental group showed significant reductions in body weight (treatment difference: -4.9%; 95% CI: -6.9% to -2.9%; p < 0.01) and BMI (treatment difference: -1.4 kg/m2; 95% CI: -1.7 to -1.2; p < 0.01) compared to placebo.
Further significant decreases in fat mass (treatment difference: -13.0%; 95% CI: -14.4 to -11.7; p < 0.01) and visceral fat rating (treatment difference: -1.3; 95% CI: -1.6 to -1.0; p < 0.01) were noted.
Homozygous minor allele carriers experienced greater decreases in body weight (treatment difference: -3.2%; 95% CI: -4.9% to -1.6%; p < 0.01) and BMI (treatment difference: -1.2 kg/m2; 95% CI: -2.0 to -0.4; p < 0.01) compared to heterozygous allele carriers.
In plain English: This study suggests that manipulating the human gut microbiome through dietary interventions could be a promising therapeutic approach to managing prediabetes and preventing or delaying diabetes.
Beteri B et al. · Nutrients (2024)
The intervention group showed a significant increase in alpha diversity and butyrate-producing bacteria, with reductions in HbA1c and FPG levels below prediabetes thresholds.
Measurements included gut microbiota composition, glycated haemoglobin (HbA1c), fasting plasma glucose (FPG), plasma lipids, anthropometry, body composition, blood pressure, and dietary intake.
No significant changes were observed in the placebo group.
18Gastrointestinal symptoms in functional constipationRCTn=66 · small study2025
In plain English: Konjac glucomannan significantly ameliorated gastrointestinal symptoms in elite athletes with functional constipation, potentially via modulation of the gut microbiota.
Zhu Y et al. · European journal of nutrition (2025)
Compared to the placebo group, the KGM group exhibited significant improvements in PAC-SYM, PAC-QoL, BMF, and BFI scores (p < 0.05 for all).
Konjac glucomannan significantly ameliorated gastrointestinal symptoms in elite athletes with functional constipation, potentially via modulation of the gut microbiota.