Benefiber vs. Metamucil: Differences, similarities, and which is better for you

In this article:

• Main differences
• Conditions treated
• Efficacy
• Cost
• Side effects
• Interactions
• Warnings
• FAQs

In this article

• Main differences
• Conditions treated
• Efficacy
• Cost
• Side effects
• Interactions
• Warnings
• 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 incidences of heart disease, better control of blood sugar, and healthy weight maintenance.

Fiber is found naturally in foods you may eat every day. There are two types of fiber: soluble and insoluble. Soluble fiber can be found in dried beans, oats, oat bran, citrus fruits, and apples, among other foods. It slows digestion and, therefore, the body’s absorption of carbohydrates (sugar). Soluble fiber also binds fatty acids and removes them from the body, lowering low-density lipoprotein (LDL) cholesterol. This is a key action for prolonged heart health. 

Insoluble fiber helps hydrate and transport waste through the intestinal tract, promoting bowel regularity and digestive system health. It is ideal to get your fiber from dietary sources because these foods are rich in other nutrients your body needs. However, data suggests that only 5% of adults consume the recommended level of dietary fiber. 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 is approved by the Food and Drug Administration (FDA) as a dietary fiber supplement. Due to its ability to add bulk to the stool, it is used off-label, or without FDA approval, as a laxative to treat constipation.

Metamucil is approved as a fiber dietary supplement and for the treatment of occasional constipation. Metamucil’s ability to build bulk in the stool helps produce bowel movements that are easier to pass. Metamucil is also indicated in the reduction of risk of coronary heart disease. This is due to its ability to bind fatty acids and remove them from the body, thereby decreasing LDL cholesterol. Metamucil is used off-label to help control blood sugar in patients with diabetes mellitus. One randomized, controlled trial showed that Metamucil may also be beneficial in decreasing symptoms of 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 will provide recommendations on which type of fiber is best for your gut health.

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 $18. If your healthcare provider writes a prescription for Benefiber, a coupon from SingleCare can lower the price to less than $10.

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 $3 with a prescription.

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. Frequency may be hard to define due to the variations in lengths of therapy as well as dosing. Patients taking Metamucil have reported nausea and vomiting, as well as asphyxiation. Rarely, hypersensitivity reactions may occur. 

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.

Source: Metamucil, Benefiber

Drug interactions of Benefiber vs. Metamucil

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.

Warnings of Benefiber and Metamucil

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 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.

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. Benefiber contains wheat dextrin, and is only approved as a fiber supplement. Metamucil contains psyllium, and in addition to being an approved fiber supplement, is also approved as a bulk-forming laxative. It also binds fatty acids to help lower LDL cholesterol.

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.

Can I use Benefiber or Metamucil while pregnant?

With adequate fluid intake, both Benefiber and Metamucil are safe to take when pregnant as they are not absorbed into the bloodstream.

Can I use Benefiber or Metamucil with alcohol?

Alcohol use with Benefiber is not contraindicated, though alcohol should always be consumed in a safe manner. When choosing a fluid to mix with your powder fiber supplement, alcohol is not recommended.

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 also has been shown to reduce heart disease by reducing 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.