Summary of results

• THE glucomannan increases satiety And reduces appetite significantly.
• He lowers LDL and total cholesterol, And slightly improves fasting blood sugar.
• He is effective against constipation, by increasing the frequency and quality of stools.
• He favorably modifies the microbiota, in particular by enriching the bifidobacteria
• It promotes the production ofshort-chain fatty acids (SCFAs), beneficial for intestinal health.

Clinical efficacy of the “Organic Konjac” formula

Konjac (Amorphophallus konjac) and glucomannan: review of human clinical trials

THE glucomannan Konjac is a highly viscous soluble fiber studied for its effects on weight, lipids and blood sugar, as well as on intestinal transit and microbiota. Below, we summarize the main clinical trials by area:

✔ Weight loss and appetite regulation

- Studies on appetite : In a crossover study in 16 healthy subjects, Au-Yeung et al. (2018) replaced part of a high-starch meal with very high konjac noodles (0%, 50%, or 100% glucomannan).
The results : meals 50 % and 100 % konjac resulted in a sharp reduction in energy intake in the next meal (–23 % and –47 % of energy consumed) compared to the control meal pubmed.ncbi.nlm.nih.gov.
This indicates that konjac fiber can increase satiety and decrease appetite.
(Note: feelings of hunger/fullness were paradoxically worse for meal 100 % KGM, but total consumption was much lower.)

- Meta-analyses (adults) : Onakpoya et al. (2014) analyzed 8 trials (≈418 subjects) and found no significant weight loss with glucomannan (mean difference ~–0.22 kg, p>0.05 vs placebo) pubmed.ncbi.nlm.nih.govThe authors conclude that the available evidence does not support a weight-loss action.

- Randomized trials (adults) : For example, Keithley et al. (2013) subjected 53 adults (BMI 25–35) to 8 weeks of glucomannan (1.33 g before each meal, ≈4 g/day) or placebo. The result : no difference in weight loss (–0.40 kg vs –0.43 kg) or change in appetite pubmed.ncbi.nlm.nih.gov. Satiety, body composition and metabolism (lipids, glucose) parameters remained comparable to controls.

- Children and adolescents : A trial in 96 obese children/adolescents (3 g/day for 12 weeks, identical dietary advice) did not show any effect on BMI or weight loss (change in BMI z-score ~0 in both groups) pubmed.ncbi.nlm.nih.gov.

Conclusion : Overall, clinical evidence is neutral or negative on weight loss itself : meta-analyses and randomized trials show none significant weight loss with glucomannan pubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.gov.

Only controlled dietary studies indicate a decrease in calorie intake via greater satiety pubmed.ncbi.nlm.nih.gov.

✔ Cholesterol and triglycerides

- Reduction of LDL cholesterol: A meta-analysis by Hoang et al. (2017) (12 trials, adults) shows that on average 3 g/d of glucomannan reduces LDL-cholesterol by about –0.35 mmol/L (–10%) and non-HDL cholesterol of approximately –0.32 mmol/L (–7%) nutraingredients-usa.com.
This study concludes that ~3 g/d is sufficient for these significant reductions in LDL.

- Total cholesterol : In a recent systematic review (2024) of 14 RCTs, glucomannan supplementation induced a decrease significant total cholesterol (SMD –3.30, p<0.001) and LDL (SMD –2.99, p≈0.006) bmccardiovascdisord.biomedcentral.com.
For example, the study found a mean reduction in LDL of about –0.3 mmol/L (p<0.01); triglyceride, on the other hand, was not reliably changed (no statistical differences) bmccardiovascdisord.biomedcentral.comThese results confirm a positive lipid effect of KGM.

- Clinical trials (children): The Zalewski (2019) trial in children reported a modest decrease in total and LDL cholesterol in the KGM group (3 g/d) compared to placebo after 12 weeks pubmed.ncbi.nlm.nih.gov. Thus, even in obese children, glucomannan tends to improve the lipid profile.

- Triglycerides : Most studies did not find a marked effect on triglycerides. For example, the 2024 meta-analysis noted that TG remained unchanged (p≈0.79) bmccardiovascdisord.biomedcentral.com.
Generally speaking, the main benefit lies on LDL-cholesterol (and total cholesterol), with neutral effect on triglycerides.

✔ Blood sugar (diabetes and carbohydrate metabolism)

- Fasting blood sugar : Mirzababaei et al. (2022) analyzed 6 trials (124 subjects) and found that glucomannan slightly reduced fasting blood glucose by –0.60 mmol/L (p=0.03) on average pubmed.ncbi.nlm.nih.govThis modest effect is statistically significant but clinically mild.

- Postprandial glycemia : In the same meta-analysis, postprandial blood glucose (2h after loading) was not significantly lowered (WMD≈–2.07 mmol/L, p=0.18) pubmed.ncbi.nlm.nih.gov.
In contrast, a recent meta-analysis in type 2 diabetics (Zhang 2023) reports significant decreases in both fasting and postprandial glucose, as well as a decrease in fasting insulin.mdpi.comThe contradiction may be explained by the fact that the included studies differ (healthy subjects vs. diabetics).

- Conclusion : Overall, the addition of glucomannan shows a slight improvement glycemic control, especially fasting blood sugar pubmed.ncbi.nlm.nih.gov.
The effect on postprandial glycemia is less clear. These results suggest a modest benefit for glycemic regulation, complementary to its lipid-lowering effect.

✔ Intestinal transit and constipation : All trials report an increase in stool frequency under glucomannan.
For example, Chen et al. (2006) observed in healthy adults (4.5 g/d KGM) an increase in daily defecation of approximately +27% (p<0.05) pubmed.ncbi.nlm.nih.gov.
In children with brain damage (chronic constipation), Staiano et al. (2000) also noted a significant increase in stool frequency with KGM (p<0.01) pubmed.ncbi.nlm.nih.gov.


- Consistency and comfort : In Staiano's pediatric study, glucomannan also improved fecal consistency (clinical score) and reduced episodes of painful defecation (p<0.01) pubmed.ncbi.nlm.nih.gov.
Similarly, constipated patients decreased their use of laxatives/suppositories with KGM pubmed.ncbi.nlm.nih.gov.
In summary, glucomannan acts as a mild laxative, making stools easier to pass.

Conclusion : Glucomannan is useful for relieving constipation : it significantly increases the frequency of stools and improves their consistency pubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.gov.
In practice, trials typically recommend 3–6 g/day (divided over meals) to observe these effects.

✔ Other potential effects (microbiota, digestive health)

- Prebiotic effect : As a fermentable fiber, glucomannan promotes the growth of beneficial bacteria. One study in adults showed that 4.5 g/d of KGM increase significantly the fecal concentration of lactobacilli and the total number of beneficial bacteria (bifidobacteria, lactobacilli) pubmed.ncbi.nlm.nih.gov.
Similarly, supplementation increased daily production of bifidobacteria and lactobacilli.

- Short-chain fatty acids (SCFAs) : This fermentation produces SCFAs. Under KGM, a decrease in colonic pH and an increase in the concentrations of acetate, propionate and butyrate in the stool are observed. pubmed.ncbi.nlm.nih.gov. For example, Chen (2006) reports a marked increase in fecal SCFAs (acetate, propionate, i-butyrate) during the glucomannan phase pubmed.ncbi.nlm.nih.gov.

- Other observations : Some studies also suggest an indirect effect on hormonal appetite (via GLP-1), but clinical data are limited. The digestive benefits of konjac seem mainly linked to its fibrous action: increase in fecal bolus and modulation of the intestinal microbiota.

Conclusion : Konjac/glucomannan improves gut health beyond its laxative effect. It enriches gut bacteria. friends », increases SCFA production and lowers colonic pH pubmed.ncbi.nlm.nih.govThese effects probably contribute to its benefits on transit and perhaps on overall metabolism (cholesterol, blood sugar).

General conclusion

Clinical studies show that konjac glucomannan is effective in terms of appetite loss but little active to induce weight loss (neutral effects on body weight in the vast majority of trials pubmed.ncbi.nlm.nih.gov).

He has positive effects on lipid balance (moderate reduction in LDL-cholesterol and total cholesterol with ~3–5 g/d) nutraingredients-usa.combmccardiovascdisord.biomedcentral.com, as well as on the fasting blood sugar (slight reduction, e.g. –0.6 mmol/L) pubmed.ncbi.nlm.nih.gov.

THE triglyceride profile remains generally unchanged. Digestively, glucomannan increases stool frequency and volume and relieves constipationpubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.gov, while promoting a microbiota rich in bifidobacteria and lactobacillipubmed.ncbi.nlm.nih.gov.

In summary, konjac (glucomannan) is clinically effective in improving certain parameters of metabolism (notably cholesterol) and intestinal function, but it is not a slimming agent. miracle ".
Its observed beneficial effects depend on the dosage (often ~3–6 g/day) and the profile of the subjects (e.g. obese vs. diabetic) nutraingredients-usa.compubmed.ncbi.nlm.nih.gov. The results are overall positive on loss of appetite, LDL cholesterol And transit, modest on blood sugar, And poor on weight loss (neutral) pubmed.ncbi.nlm.nih.govnutraingredients-usa.comThese conclusions are supported by available meta-analyses and RCTs.

Sources: Meta-analyses and RCTs mentioned above (PubMed/DOI) pubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.govnutraingredients-usa.combmccardiovascdisord.biomedcentral.compubmed.ncbi.nlm.nih.govmdpi.compubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.gov