Form Comparison

Methylcellulose vs Psyllium Husk

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

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Quick verdict. Psyllium does more: it softens hard stool, firms loose stool, and lowers LDL cholesterol. Methylcellulose (Citrucel) is a bulk laxative that gut bacteria do not ferment, so it causes almost no gas, but it lacks psyllium's cholesterol evidence. Choose psyllium unless it gives you too much gas or bloating, then switch to methylcellulose for constipation.

Side by Side

Methylcellulose Psyllium Husk
How it works Semisynthetic, soluble, non-fermented fiber that adds water-holding bulk to stool. 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 2 g 1-3 times daily 5-10 g powder 1-3 times daily with ample water
Common uses constipation with minimal gas constipation, diarrhea and IBS, LDL cholesterol lowering, glycemic control
Side effects Minimal gas because gut bacteria do not ferment it. Bloating at first; must be taken with enough water. Separate from medications by at least 2 hours.
Cost Low Low
Also called Citrucel ispaghula, Plantago ovata

When to Choose Methylcellulose

Choose methylcellulose when you need a laxative bulk fiber and psyllium causes gas. Does not share psyllium's cholesterol-lowering evidence.

Methylcellulose

A gas-free laxative, and nothing more.

What to look for: Useful when psyllium causes bloating. No cholesterol or glucose effect.

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.