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Before You Buy Fiber Supplements

What You Need To Know Before You Choose A Fiber Supplement


Updated July 08, 2014


Fiber supplements can help with both diarrhea and constipation, but not every type works best for every person.

Photo © Pawel Kryj

Not all fiber supplements are created equally. There are three main types of soluble fiber supplements: psyllium, methylcellulose, and polycarbophil. Each type of fiber has varying uses, side effects, and properties. Talk with your doctor about fiber supplements to determine which is best for your body. When shopping for fiber, look closely at the ingredients to discover which type of fiber is used in each commercial brand. Remember to start at a low dose and drink plenty of water.


Brand names: Metamucil, Fiberall, Hydrocil, Konsyl, Perdiem, Serutan

Psyllium is a fiber supplement that can be taken every day to bulk up stool, making it easier to pass. It works by breaking down in the gut and becoming a food source for the "good bacteria" there. It is used for treating constipation, irritable bowel syndrome (IBS) and diverticulosis. In addition, psyllium may also lower cholesterol levels by 10 to 15 percent. On the downside, psyllium does contain calories and may cause gas.


Brand name: Citrucel

Methylcellulose is a fiber that is nonallergenic, non-fermentable, can be taken every day, and is created from the cell wall of plants. It is not absorbed by the intestinal tract but instead absorbs water to create a softer stool. Methylcellulose is often used to treat constipation, diverticulosis, irritable bowel syndrome, and some cases of diarrhea. Because it does not ferment, it is less likely to cause intestinal gas.


Brand names: Fibercon, Fiber-Lax, Equalactin, Mitrolan

Similar to methylcellulose, polycarbophil is created from plants and is not absorbed by the body. It absorbs water in the intestinal tract and creates a bulkier and softer stool. Polycarbophil is less likely to cause bloating and can be used long term. It may be used to treat constipation, IBS and diverticulosis. This form of fiber is not appropriate for people who have difficulty swallowing.


Natural Standard Research Collaboration. "Psyllium." MedlinePlus 26 Dec 2012. 7 Apr 2014.

Drug Digest. "Psyllium Capsules." Drug Digest 2 Apr 2014. 7 Apr 2014.


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