BioStacks

Supplement

Konjac Root Fiber

Evidence

Moderate
Evidence: 3 of 5 (Moderate)

What the evidence says

Glucomannan is a soluble, gel-forming fiber from Amorphophallus konjac that swells up to 50× its weight in water, slowing gastric emptying and blunting postprandial glucose. Cholesterol-lowering evidence is the strongest: a meta-analysis of 14 RCTs (Sood et al., 2008, PMID 18842808) found ~3 g/day reduced LDL by ~10% and total cholesterol by ~7%.

Meta-analyses confirm cholesterol reduction at 3 g/day; weight-loss claims are mechanistic (satiety) — RCT meta-analysis found no significant body-weight effect

Top Konjac Root Fiber supplements

About Konjac Root Fiber

Glucomannan is a soluble, gel-forming fiber from Amorphophallus konjac that swells up to 50× its weight in water, slowing gastric emptying and blunting postprandial glucose. Cholesterol-lowering evidence is the strongest: a meta-analysis of 14 RCTs (Sood et al., 2008, PMID 18842808) found ~3 g/day reduced LDL by ~10% and total cholesterol by ~7%. Weight-loss evidence is weaker — a 2014 meta-analysis of 8 RCTs (Onakpoya et al., PMID 24356469) found NO statistically significant short-term effect on body weight in overweight/obese adults, contradicting earlier smaller trials. EFSA approved a weight-loss claim at 3 g/day in 2010 based on satiety mechanisms, not body composition outcomes. SAFETY: tablets/capsules can swell in the esophagus and cause obstruction or choking — the FDA forced reformulation of glucomannan tablets in the 1980s, and EFSA mandates a choking warning. Always take with ≥240 mL water, well before lying down. May reduce absorption of oral medications taken simultaneously; separate by ≥1 hour. Use caution with diabetic medications (additive glycemic lowering).

What Konjac Root Fiber supports

  • Lowers LDL cholesterol ~10% at 3 g/day (meta-analysis of 14 RCTs)
  • Promotes satiety via viscous gel in the stomach — EFSA-approved at 3 g/day
  • Blunts postprandial glucose when taken before carb-heavy meals

How much Konjac Root Fiber to take

The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.

Effective

3000–4000

mg

EFSA approved a satiety/weight-management claim at 3 g/day taken with water before meals (3×1 g). Health Canada approves cholesterol-lowering claims at ≥4 g/day. RCTs for satiety and glycemic control typically use 2–4 g/day divided before meals. Doses below ~3 g/day rarely produce measurable outcomes in trials.

Clinical evidence

Moderate clinical evidence. Meta-analyses confirm cholesterol reduction at 3 g/day; weight-loss claims are mechanistic (satiety) — RCT meta-analysis found no significant body-weight effect

Examine.com