Benefiber vs. Metamucil: Which fiber supplement is better?

In this article:

• Main differences
• Conditions treated
• Efficacy
• Cost and insurance coverage
• Side effects
• FAQs

In this article

• Main differences
• Conditions treated
• Efficacy
• Cost and insurance coverage
• Side effects
• FAQs

Fiber is a key component of a healthy diet. Fiber helps with bowel regularity and colon health. Fiber adds bulk to the stool and holds water, making stools easier to pass. Healthy fiber intake has other potential benefits, such as lower incidence of heart disease, better control of blood sugar, and healthy weight maintenance. If your diet does not contain enough fiber, you may need to take a fiber supplement such as Benefiber or Metamucil. 

What are the main differences between Benefiber and Metamucil?

Benefiber is an over-the-counter (OTC) soluble fiber supplement. The active ingredient in Benefiber is wheat dextrin. Benefiber absorbs water in the intestinal tract. This stimulates peristalsis, the repetitive contraction and relaxation of the intestinal muscle. While this process ultimately moves intestinal contents, it slows the transit time through the intestine. Benefiber is available as a powder and in oral or chewable tablets and gummies. There are sugar-free and gluten-free formulations available as well.

Metamucil is an OTC soluble fiber made from psyllium husks, which come from the seeds of an Indian herb known as Plantago ovata. Metamucil works in the same manner as Benefiber, stimulating peristalsis and slowing intestinal transit. It is available as a powder, capsules, wafers, and gummies. Some formulations are also sugar-free and gluten-free.

Conditions treated by Benefiber and Metamucil

Benefiber uses:

• Fiber supplement for digestive health and feeling fuller longer
• Occasional constipation

Metamucil uses:

• Fiber supplement for digestive health and appetite control
• Occasional constipation
• Heart health/lowering cholesterol
• Blood sugar management 
• Irritable bowel syndrome

Is Benefiber or Metamucil more effective?

A clinical review published in 2015 sought to evaluate the health outcomes of regular fiber therapy by comparing commercially available fiber products. Researchers describe that a key difference between dextrin (Benefiber) and psyllium (Metamucil) is that dextrin is readily fermented in the intestinal tract. Once fermented, dextrin loses its water-holding capability and, therefore, is not an effective laxative. Psyllium is not fermented and thus becomes a viscous, gel-like consistency and can hold water in the stool throughout the large bowel. This provides a hydrated, bulky stool that can be excreted more easily. Furthermore, the American College of Gastroenterology Chronic Constipation Task Force published findings that psyllium was the only fiber supplement that showed enough clinical evidence to support an indication for chronic constipation.

The American Diabetes Association published a meta-analysis in 2019 evaluating fiber supplements’ effects on glycemic control. Their findings suggested that viscous fibers, like psyllium, showed the greatest effect on glycemic control. Psyllium’s viscous gel formation slows digestion, likely slowing sugar absorption. This effect of slowing digestion also leaves you feeling fuller for a longer period of time, seeming to aid in weight loss.

A randomized, placebo-controlled trial published in 2012 evaluated psyllium’s effects on LDL cholesterol in adolescent males with risk factors for heart disease. Psyllium therapy of just 6 g per day was found to significantly lower cholesterol, specifically LDL, by 6%. 

Your healthcare provider can provide recommendations on which type of fiber is best for your gut health, based on your individual health history.

Benefiber vs Metamucil for weight loss

Benefiber Original, according to the manufacturer, helps you feel fuller longer when taking the recommended dose of 3.5 teaspoons twice daily. Metamucil is also used for appetite control. While they are both used for appetite control, they do not directly cause weight loss. However, fiber is known to help control appetite and make you feel fuller longer. Since both Benefiber and Metamucil are fiber supplements, either one could help with appetite control, which could help support weight loss. You can check with your healthcare provider if you have questions about which product would be best for you. 

Coverage and cost comparison of Benefiber vs. Metamucil

Benefiber is an OTC supplement that is not typically covered by commercial or Medicare insurance. Typical retail packaging for Benefiber would be a 248 g bottle, which can cost as much as $21. If your healthcare provider writes a prescription for Benefiber, a coupon from SingleCare can lower the price to about $10 at Walgreens.

Benefiber coupons

Metamucil is also an OTC supplement that is not generally covered by commercial or Medicare insurance. Common packaging would be a box containing 44 dose packets of Metamucil powder. At full retail price, this may cost more than $30. A coupon from SingleCare would make it possible to get a Metamucil equivalent for around $9 at Walgreens with a prescription.

Metamucil coupons

Prescription drug prices often change. These are the most accurate medication prices at the time of publishing in ZIP code 23666 as of 11/17/25. The listed price without insurance references the price of brand-name drugs (unless otherwise specified). The listed SingleCare price references the price of generic drugs if available.

RELATED: How to use SingleCare savings with OTC products

Common side effects of Benefiber vs. Metamucil

The most reported side effect of fiber therapy is flatulence or gas build-up in the gastrointestinal tract. Adverse events associated with Benefiber and Metamucil appear to be relatively rare but may also include stomach pain (cramping) and bloating. Patients taking Metamucil have reported nausea and vomiting. Rarely, hypersensitivity reactions may occur. If you have symptoms of an allergic reaction, like hives, trouble breathing, or swelling, you should get emergency medical help right away.

There are sugar-free formulations of these fiber supplements, but they may use artificial sweeteners in place of sugar. Read your product ingredients to check for other ingredients you may be sensitive to.

The following list is not intended to be a complete list of possible side effects. Please consult a pharmacist or healthcare provider for a complete list of possible side effects.

Benefiber side effects

• Flatulence (gas)
• Stomach discomfort
• Bloating

Metamucil side effects

• Flatulence (gas)
• Stomach discomfort
• Bloating
• Nausea and vomiting

Benefiber vs. Metamucil interactions and warnings

It is important to take Benefiber and Metamucil products with adequate fluid intake. Fiber therapy without adequate fluid intake can lead to esophageal blockage and choking. Do not take these products if you have difficulty swallowing. If you experience chest pain, vomiting, or difficulty in swallowing or breathing, seek medical attention immediately.

If you experience constipation for more than seven days or if you experience rectal bleeding while taking Benefiber or Metamucil, contact your healthcare provider immediately.

Benefiber and Metamucil powders are gluten-free, though some other products made by these brands may not be. Patients with celiac disease should read the label and consult a healthcare professional to ensure the fiber product they have chosen is safe.

There are no known drug interactions with either Benefiber or Metamucil. Bulk-forming fiber like Metamucil may affect how other medications are absorbed. The manufacturer recommends that you take your Metamucil two hours before or two hours after your prescribed medication.

Frequently asked questions about Benefiber vs. Metamucil

Are Benefiber and Metamucil the same?

Benefiber and Metamucil are both fiber supplements, but they are not the same. Both are used as a fiber supplement and for appetite control. Metamucil is also used as a laxative and to lower cholesterol and support heart health. 

Is Benefiber or Metamucil better?

Metamucil has been shown to be a more effective laxative due to the fact that it is not fermented in the human bowel. This allows it to hold water throughout the intestinal tract and slows digestion. Slower digestion has been shown to help with glycemic control and weight loss as well. However, individual experiences may vary, so you may need to try more than one fiber supplement to find the best one for you. 

Which is better for diarrhea?

Healthcare providers may recommend either Benefiber or Metamucil in people with chronic diarrhea. Both contain fiber, which can help absorb excess water in the intestines and improve the consistency of your stools. 

Which fiber supplement is best?

Metamucil has been shown to have more health benefits overall versus Benefiber. In addition to being a fiber supplement, Metamucil is a proven bulk-forming laxative. It has also been shown to reduce the risk of heart disease by lowering LDL cholesterol. Its effect on slowing digestion time helps maintain glycemic control and may aid in weight loss.

Should you take fiber before or after a meal?

You can take your fiber before, during, or after meals. When taking fiber as an adjunctive therapy for diabetes, one study suggests taking it just before starting your meal to help slow digestion and decrease appetite.

How long does it take Benefiber and Metamucil to work for constipation? 

 It can take anywhere from one to three days for Benefiber or Metamucil to help improve constipation. For best results, follow the instructions on the label for your product and take with plenty of water.