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ingestible · for weight management

Glucomannan (Konjac Fiber)

Reviewed by the Nimbera editorial team · Last updated May 2026

Systematic review of 6 RCTs (Zalewski et al. Nutrition 2015, PMID 25701331) found glucomannan produced statistically significant short-term body weight reductions of up to 3.17 kg vs. placebo at 8 weeks. Evidence is modest - effects are likely mediated through satiety and reduced caloric intake.$15-$25 per month.

How to use

Take 1-3 g of glucomannan capsules with a full glass of water 30-60 minutes before meals. Do not take in powder form without adequate water. Start with 1 g per meal and increase gradually.

How it works

Glucomannan is a highly viscous soluble fiber from the konjac root. It absorbs many times its weight in water, expanding in the stomach to promote fullness, delay gastric emptying, and blunt post-meal blood glucose spikes.

Where to buy

Health food stores and online. Look for Lipozene (branded) or generic konjac/glucomannan capsules. Ensure the product specifies glucomannan content per capsule.

Typical cost: $15-$25 per month.

Safety notes

Must be taken with plenty of water - glucomannan can cause choking or esophageal blockage if swallowed without sufficient fluid. May reduce absorption of oral medications; take glucomannan at least 2 hours before or after medications. Can cause bloating, flatulence, and loose stools. Not appropriate as a sole weight loss strategy.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

Clinical source

Zalewski et al. Nutrition 2015 - PMID 25701331

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.