# GlucomannanPlus (Amorphophallus konjac)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/glucomannanplus
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-01
**Evidence Score:** 2 / 10
**Category:** Other
**Also Known As:** Amorphophallus konjac, konjac glucomannan, konjac fiber, konjac root extract, elephant yam, devil's tongue, voodoo lily, snake palm, konnyaku, shirataki fiber, E425

## Overview

GlucomannanPlus is a highly viscous soluble fiber derived from the konjac root (Amorphophallus konjac), with konjac glucomannan (KGM) as its primary bioactive polysaccharide. It exerts its effects by forming a dense gel in the gastrointestinal tract, slowing gastric emptying, blunting postprandial glucose absorption, and increasing fecal bile acid excretion to reduce cholesterol.

## Health Benefits

• May support healthy [blood glucose](/ingredients/condition/weight-management) levels - Meta-analysis of 6 RCTs showed significant reduction in fasting blood glucose (WMD: -0.60 mmol/L, P=0.03)
• Potential cholesterol management in children - One 8-week RCT showed reductions in total cholesterol (24% females, 9% males) and LDL-C (30% females, 9% males) when combined with Step-One-Diet
• Limited evidence for weight loss - Meta-analysis of 8 RCTs found non-significant weight reduction (MD: -0.22 kg) in overweight/obese adults
• No significant benefit for pediatric abdominal pain - RCT with 84 children showed no difference vs placebo for pain relief (29% vs 14%, not significant)
• Possible fiber-related digestive effects - As a soluble fiber, may influence gastrointestinal function through bulk-forming properties

## Mechanism of Action

Konjac glucomannan (KGM) absorbs up to 50 times its weight in water, forming a high-viscosity gel that slows gastric emptying and reduces the rate of glucose diffusion across the intestinal epithelium, thereby attenuating postprandial insulin and glucose spikes. KGM also binds bile acids in the intestinal lumen, interrupting enterohepatic recirculation and compelling the liver to upregulate LDL receptor expression and convert additional cholesterol into bile acids via the CYP7A1 enzyme pathway. Additionally, KGM acts as a [prebiotic](/ingredients/condition/gut-health) substrate for colonic fermentation, increasing short-chain fatty acid (SCFA) production—particularly propionate—which inhibits hepatic gluconeogenesis via GPR41/GPR43 receptor signaling.

## Clinical Summary

A meta-analysis of 6 randomized controlled trials demonstrated that konjac glucomannan supplementation produced a statistically significant reduction in fasting [blood glucose](/ingredients/condition/weight-management) (weighted mean difference: -0.60 mmol/L, P=0.03), though the number of trials remains modest and larger confirmatory studies are needed. A separate 8-week RCT in children found notable reductions in total cholesterol (24% in females, 9% in males) and LDL-C (30% in females), suggesting potential utility in pediatric dyslipidemia management. Evidence for weight management is supported by glucomannan's ability to increase satiety through gastric gel formation, though effect sizes on body weight in adults are generally modest across trials. Overall, the evidence is promising but limited by small sample sizes, heterogeneous dosing protocols, and short study durations.

## Nutritional Profile

GlucomannanPlus (Amorphophallus konjac) is a highly purified dietary fiber supplement with minimal caloric density. Primary bioactive compound: konjac glucomannan (KGM), a high-molecular-weight soluble polysaccharide composed of glucose and mannose units in a ~1:1.6 ratio, linked by β-1,4-glycosidic bonds, with β-1,3-linked branch points approximately every 50-60 units. Typical glucomannan content in commercial supplements: 40-60% by dry weight per capsule/serving (commonly 500mg-1g per capsule). Macronutrient profile per typical 3g serving: Carbohydrates ~2.5-3g (almost entirely soluble dietary fiber), Protein <0.1g, Fat <0.1g, Calories ~5-10 kcal. Micronutrients: Negligible intrinsic vitamin or mineral content. Bioactive properties: Exceptionally high water-holding capacity (can absorb up to 50x its weight in water), forming a viscous gel in the gastrointestinal tract. Molecular weight of KGM: approximately 200,000-2,000,000 Da, with higher molecular weight correlating with greater viscosity and likely greater physiological effect. Bioavailability notes: KGM is not digested by human small intestinal enzymes and reaches the colon largely intact, where it undergoes partial fermentation by gut microbiota producing short-chain fatty acids (SCFAs: acetate, propionate, butyrate). The viscous gel matrix slows gastric emptying and nutrient absorption, which underlies its effects on postprandial glucose and cholesterol. Acetylation degree (~5-10% of hydroxyl groups) influences solubility and fermentability.

## Dosage & Preparation

Clinical studies have not provided specific dosage details in the available abstracts. One trial used glucomannan in gelatin capsules over 8 weeks, while another used purified glucomannan fiber supplementation for the same duration. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Glucomannan is generally well tolerated, but its rapid gel-forming properties create a risk of esophageal or intestinal obstruction if tablets are swallowed without sufficient water; powder or capsule forms taken with at least 240 mL of water are strongly preferred. Common gastrointestinal side effects include bloating, flatulence, loose stools, and abdominal discomfort, particularly at doses above 3–4 g/day or during initial use. Glucomannan may delay the absorption of oral medications—including antidiabetic agents like metformin and sulfonylureas—potentially amplifying hypoglycemic effects; medications should be taken at least 1 hour before or 4 hours after glucomannan supplementation. Safety data in pregnancy and lactation are insufficient to establish clear recommendations, and use in these populations should be undertaken only under medical supervision.

## Scientific Research

Clinical evidence includes a meta-analysis of 6 RCTs (n=124) showing glucomannan reduced fasting [blood glucose](/ingredients/condition/weight-management) (PMID: 35673426), and a meta-analysis of 8 RCTs examining weight loss effects with non-significant results (PMID: 24533610). Additional studies include an 8-week trial in hypercholesterolemic children (PMID: 15955465) and a pediatric functional GI disorder RCT (PMC3662945).

## Historical & Cultural Context

No historical or traditional medicine context was provided in the research results. The konjac plant is native to East Asia but traditional uses were not detailed in the available studies.

## Synergistic Combinations

Chromium, Cinnamon extract, Green tea extract, Alpha-lipoic acid, [Probiotic](/ingredients/condition/gut-health)s

## Frequently Asked Questions

### How much glucomannan should I take per day for blood sugar control?

Most clinical trials supporting blood glucose reduction used doses of 3–4 grams of konjac glucomannan per day, typically divided into doses taken before meals with a full glass of water. The meta-analysis showing a -0.60 mmol/L reduction in fasting blood glucose generally used doses within this range over periods of 4–12 weeks. Always consult a healthcare provider before use, especially if taking antidiabetic medications, due to additive hypoglycemic risk.

### Does glucomannan actually help with weight loss?

Glucomannan can contribute modestly to weight loss primarily by forming a viscous gel in the stomach that delays gastric emptying, prolongs satiety signaling, and reduces overall caloric intake. Randomized trials have reported weight reductions of approximately 0.4–0.8 kg over 5–8 weeks compared to placebo when taken before meals at 3 g/day. However, effects are modest and work best as an adjunct to a calorie-controlled diet rather than as a standalone intervention.

### Is glucomannan safe for children with high cholesterol?

A published 8-week RCT found that glucomannan supplementation reduced total cholesterol by up to 24% in girls and 9% in boys, and LDL-C by approximately 30% in females, suggesting a meaningful lipid-lowering effect in the pediatric population. Glucomannan is considered a dietary fiber and has a favorable safety profile in children, with gastrointestinal discomfort being the primary reported side effect. Nonetheless, pediatric supplementation should always be supervised by a physician who can monitor lipid panels and ensure appropriate dosing by body weight.

### Can glucomannan interfere with my medications?

Yes—because konjac glucomannan forms a viscous gel throughout the gastrointestinal tract, it can physically delay or reduce the absorption of orally administered drugs, including metformin, sulfonylureas, levothyroxine, and fat-soluble vitamins. To minimize this interaction, all oral medications should be taken at least 1 hour before or 4 hours after glucomannan supplementation. Patients on anticoagulants or insulin therapy should notify their prescriber before starting glucomannan due to potential compounding effects on glucose and bleeding parameters.

### What is the difference between glucomannan and regular fiber supplements like psyllium?

Konjac glucomannan (KGM) has an exceptionally high molecular weight (200,000–2,000,000 Da) and forms a gel approximately 10-fold more viscous than psyllium husk at equivalent concentrations, which translates to stronger effects on gastric emptying delay and bile acid sequestration. Psyllium is primarily composed of arabinoxylan and is better studied for its direct cholesterol-lowering effects via FDA-recognized heart health claims, while glucomannan's evidence base is strongest for glycemic control and satiety. Both function as soluble dietary fibers and prebiotic substrates, but their viscosity profiles and fermentation rates in the colon differ, with KGM fermented more rapidly to produce short-chain fatty acids.

### What is the difference between GlucomannanPlus and other konjac fiber products on the market?

GlucomannanPlus is a branded formulation of Amorphophallus konjac, which is the same plant source used in generic glucomannan supplements. The key difference lies in the manufacturing process, purity standards, and potential additional ingredients in the branded version that may enhance bioavailability or efficacy. Without specific proprietary additives disclosed, GlucomannanPlus and standard glucomannan supplements deliver essentially the same active component—konjac glucomannan soluble fiber.

### Are there specific populations that should avoid GlucomannanPlus?

People with swallowing difficulties, esophageal obstruction, or bowel obstruction should avoid glucomannan products including GlucomannanPlus, as the ingredient expands significantly in the digestive tract and may pose a choking or blockage risk. Additionally, individuals with severe gastrointestinal conditions or those scheduled for gastrointestinal surgery should consult a healthcare provider before use. Adequate water intake is essential to prevent adverse effects, making this ingredient unsuitable for those unable to consume sufficient fluids.

### How strong is the clinical evidence supporting GlucomannanPlus for blood sugar management?

Meta-analysis data shows moderate evidence for glucomannan's effect on fasting blood glucose, with a significant reduction of 0.60 mmol/L demonstrated across 6 randomized controlled trials. While this reduction is statistically significant, the clinical magnitude is modest and may be most beneficial as part of a comprehensive dietary approach rather than as a standalone treatment. More research is needed to determine optimal dosing and long-term efficacy for sustained blood glucose control.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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