Yes, Benefiber is a soluble fiber supplement. Its active ingredient is wheat dextrin, a glucose polymer derived from wheat starch that dissolves completely in water. Per 100 grams of total dietary fiber in Benefiber, roughly 83 grams is soluble fiber, making it almost entirely soluble.
What Wheat Dextrin Is and How It Works
Wheat dextrin is created by breaking down wheat starch through a process of heating and partial digestion. The resulting fiber resists digestion in your small intestine because of the way its sugar molecules are linked together. Instead of being absorbed, it passes intact into your large intestine, where gut bacteria ferment it.
That fermentation feeds beneficial bacteria, particularly Bifidobacteria and Lactobacilli. In lab studies, wheat dextrin boosted Bifidobacteria populations more effectively than partially hydrolyzed guar gum, another popular soluble fiber. The fermentation also lowers the pH in the colon, which may help your body absorb certain minerals more efficiently and create a less hospitable environment for harmful bacteria.
One practical advantage: wheat dextrin produces significantly less gas during fermentation than many other fiber supplements. If bloating has been a problem with other products, this is worth noting.
Soluble but Not Gel-Forming
Not all soluble fibers behave the same way once dissolved. Some, like psyllium (the fiber in Metamucil), form a thick, viscous gel in liquid. Wheat dextrin does not. It dissolves clearly and stays thin, behaving almost like water in terms of viscosity. This is why Benefiber’s marketing emphasizes that it won’t change the taste, texture, or appearance of your drinks or food.
This distinction matters for health outcomes. Viscous, gel-forming fibers like psyllium have strong evidence for lowering cholesterol and improving blood sugar control because the gel physically slows digestion and traps bile acids. Nonviscous soluble fibers like wheat dextrin don’t do this. A clinical guide published in the American Journal of Lifestyle Medicine notes directly that wheat dextrin does not improve glycemic control or lower cholesterol the way gel-forming fibers do.
That said, resistant dextrin as a broader category does show some blood sugar benefits in specific populations. A meta-analysis of 13 randomized controlled trials found that resistant dextrin modestly reduced fasting blood sugar, with the strongest effects in people with type 2 diabetes or a BMI of 30 or above. For people with normal blood sugar and weight, the effect was minimal. Around 10 grams per day was the most commonly effective dose in those trials.
How to Use It
A standard serving is 2 teaspoons of Benefiber powder stirred into 4 to 8 ounces of any non-carbonated beverage or soft food. Each serving provides about 3 grams of fiber. You can take up to three servings per day, giving you a maximum of 9 grams of supplemental fiber. It works in both hot and cold liquids and food.
Because wheat dextrin has such low viscosity and stays clear in solution, it’s one of the easier fiber supplements to mix into coffee, smoothies, oatmeal, or soup without altering what you’re eating. It also comes in chewable tablets and caplets for people who prefer not to mix powder.
Benefiber vs. Metamucil
The two most common fiber supplements on store shelves work in fundamentally different ways, even though both contain soluble fiber.
- Benefiber (wheat dextrin): Soluble, nonviscous, fully fermentable. Dissolves clear, no texture change. Primary benefit is prebiotic, feeding beneficial gut bacteria. Does not form a gel, so it won’t help with cholesterol or blood sugar regulation through that mechanism. Produces relatively little gas.
- Metamucil (psyllium husk): Soluble, viscous, gel-forming, and largely non-fermented. Thickens noticeably in liquid. Strong clinical evidence for lowering cholesterol, improving blood sugar control, and relieving constipation by increasing stool water content. Can cause more bloating initially because of its bulk.
Your choice depends on your goal. If you want to quietly boost daily fiber intake and support gut bacteria without changing how your food tastes, Benefiber fits well. If you’re specifically trying to manage cholesterol or blood sugar, psyllium has stronger evidence for those outcomes.
Is It Safe if You Avoid Gluten?
Benefiber is derived from wheat, which raises an obvious question for anyone with celiac disease or gluten sensitivity. The manufacturing process breaks down wheat starch extensively, and Benefiber has historically been labeled gluten-free based on testing below the FDA’s threshold of 20 parts per million. However, if you have celiac disease, the wheat origin alone may give you or your gastroenterologist pause. Benefiber is not currently listed as a Monash University certified Low FODMAP product either, which is relevant if you’re following a Low FODMAP diet for irritable bowel syndrome.