Form Comparison

Glucomannan vs Psyllium Husk

How glucomannan and psyllium husk differ in how they work, evidence, tolerance, and cost.

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Quick verdict. Psyllium is the better-evidenced choice for constipation, IBS-related diarrhea, and LDL lowering, and it carries an FDA heart health claim. Glucomannan is more viscous, so a 1 g capsule does a lot, but its weight-loss effects are small and inconsistent, and it can swell and obstruct the esophagus if taken without enough water. Choose psyllium for most goals, and glucomannan only if you want viscous fiber in small capsules and will drink a full glass with each dose.

Side by Side

Glucomannan Psyllium Husk
How it works Extremely viscous soluble fiber that absorbs many times its weight in water, slowing gastric emptying. Soluble, gel-forming, minimally fermented. The gel holds water to soften hard stool and firms loose stool, and traps bile acids, which lowers LDL cholesterol.
Typical dose 1 g before meals with a full glass of water 5-10 g powder 1-3 times daily with ample water
Common uses satiety, LDL lowering, constipation constipation, diarrhea and IBS, LDL cholesterol lowering, glycemic control
Side effects Can swell and cause choking or esophageal obstruction if taken without enough water; tablet forms carry the highest risk. Bloating at first; must be taken with enough water. Separate from medications by at least 2 hours.
Cost Low Low
Also called konjac fiber, konjac root ispaghula, Plantago ovata

When to Choose Glucomannan

Choose glucomannan when you want viscous fiber in small capsule doses and will take it with plenty of water. Weight-loss effects in trials are small and inconsistent.

Glucomannan

Choose glucomannan when you want viscous fiber in small capsule doses and will take it with plenty of water.

What to look for: Glucomannan named on the Supplement Facts panel, with the amount per serving stated.

Find on iHerb Affiliate link

When to Choose Psyllium Husk

Choose psyllium husk when you want stool normalization or cholesterol lowering with the strongest evidence. Carries an FDA-authorized health claim for coronary heart disease risk reduction. Little gas because it resists fermentation.

Psyllium Husk

The most studied supplemental fiber. It lowers LDL and normalizes stool in both directions, and it improves glycemic control in proportion to how poor that control is.

What to look for: Plain psyllium husk or powder with grams of psyllium per serving, sugar-free for daily use. Start at 3-5 g.

Find on iHerb Affiliate link

Products on Titrate

2,168 of the 214,745 labels in the NIH Dietary Supplement Label Database list fiber as an active ingredient (1,232 on market). 322 are sold as fiber products by name.

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Fiber does not have its own search category yet. Each product above links to its full label in the NIH database.

Related

References

Institute of Medicine. National Academies Press, 2005. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids.

Moayyedi P, et al. The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis. Am J Gastroenterol. 2014;109(9):1367-1374.

Gibb RD, et al. Psyllium fiber improves glycemic control proportional to loss of glycemic control: a meta-analysis of data in euglycemic subjects, patients at risk of type 2 diabetes mellitus, and patients being treated for type 2 diabetes mellitus. Am J Clin Nutr. 2015;102(6):1604-1614.

McRorie JW Jr, McKeown NM. Understanding the Physics of Functional Fibers in the Gastrointestinal Tract: An Evidence-Based Approach to Resolving Enduring Misconceptions about Insoluble and Soluble Fiber. J Acad Nutr Diet. 2017;117(2):251-264.

Jovanovski E, et al. Effect of psyllium (Plantago ovata) fiber on LDL cholesterol and alternative lipid targets, non-HDL cholesterol and apolipoprotein B: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr. 2018;108(5):922-932.

McDonald D, et al. American Gut: an Open Platform for Citizen Science Microbiome Research. mSystems. 2018;3(3):e00031-18.

Reynolds A, et al. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019;393(10170):434-445.

Wastyk HC, et al. Gut-microbiota-targeted diets modulate human immune status. Cell. 2021;184(16):4137-4153.