Citrucel is a bulk-forming fiber supplement that absorbs water in your digestive tract, softening stool and making it easier to pass. Its active ingredient is methylcellulose, a synthetic soluble fiber derived from plant cellulose. Unlike many other fiber supplements, methylcellulose resists fermentation by gut bacteria, which means it’s far less likely to cause gas and bloating.
How Citrucel Works in Your Body
When you swallow Citrucel and follow it with water, the methylcellulose dissolves and forms a gel-like substance in your intestines. This gel adds bulk to your stool and holds onto moisture, which keeps things soft and moving. The added bulk gently stimulates your intestinal walls to contract, pushing stool through at a normal pace. You can generally expect a bowel movement within 12 to 72 hours of your first dose, though many people find it works best when taken consistently over several days.
Because methylcellulose is 100% soluble fiber, it blends smoothly with the contents of your gut rather than adding rough, scratchy material. This makes it a good option for people whose digestive systems are sensitive to the insoluble fiber found in bran or whole grains.
Why It Causes Less Gas Than Other Supplements
The standout feature of Citrucel is how little gas it produces. When bacteria in your colon break down fiber, they release gas as a byproduct. Methylcellulose largely resists this process. In a fermentation study comparing several fiber types, methylcellulose produced just 0.57 mL of gas per gram, while pectin (a fiber found in fruit) produced 108 mL per gram. Psyllium, the fiber in Metamucil, fell somewhere in between. That’s a massive difference, and it explains why Citrucel is often recommended for people who experience uncomfortable bloating from other fiber sources.
This low fermentation rate also means methylcellulose produces very few short-chain fatty acids compared to other fibers. Those fatty acids can be beneficial for colon health, so Citrucel trades some of that gut-health benefit for digestive comfort. If bloating and gas are your main barriers to using a fiber supplement, that tradeoff is often worth it.
Common Reasons People Take It
Most people reach for Citrucel to relieve occasional constipation or to stay regular. By adding bulk and moisture to stool, it addresses the most common cause of infrequent bowel movements: not enough fiber in the diet.
It’s also used by people managing irritable bowel syndrome. The Mayo Clinic notes that some people with IBS do better limiting dietary fiber from food and instead using a supplement that causes less gas and bloating, specifically naming Citrucel as an option. The key is introducing it slowly and drinking plenty of water each day. For people with IBS who react poorly to high-fiber foods, a low-fermentation supplement can provide the regularity benefits of fiber without triggering a flare.
How Citrucel Compares to Metamucil and Benefiber
All three are fiber supplements, but they work a bit differently. Citrucel and Benefiber are both 100% soluble fiber, while Metamucil is a blend of soluble and insoluble fiber. The active ingredient in Metamucil is psyllium husk, which ferments more than methylcellulose and tends to produce more gas. Benefiber uses wheat dextrin, which also ferments more readily and is not suitable for people avoiding gluten.
Citrucel is gluten-free and labeled as non-allergenic, making it a safer pick for people with celiac disease or wheat sensitivities. If your main priority is minimizing digestive discomfort while still getting a fiber supplement, Citrucel has the edge. If you want a fiber that also feeds beneficial gut bacteria through fermentation, psyllium or wheat dextrin may be a better fit. None of these supplements, however, provide the full range of protective benefits you get from eating whole foods rich in fiber.
Available Forms and What’s in Them
Citrucel comes in two main powder formulations, both orange-flavored, plus caplet form for people who prefer swallowing a tablet.
- Citrucel Orange (regular): Each heaping tablespoon contains 60 calories, mostly from sucrose and maltodextrin. It’s the original version and tastes mildly sweet.
- Citrucel Sugar Free: Each rounded tablespoon contains 30 calories from maltodextrin. It uses aspartame as a sweetener, so it carries a warning for people with phenylketonuria (a rare metabolic condition). Each adult dose contains 48.6 mg of phenylalanine.
Both powder versions are gluten-free, 100% soluble fiber, and non-allergenic. They do contain soy lecithin, which is worth noting if you have a soy allergy, though lecithin is generally tolerated even by most soy-sensitive individuals.
Important Safety Considerations
The single most important rule with Citrucel is drinking enough water. Each dose should be followed with at least 8 ounces of water. Without adequate fluid, the powder can swell in your throat or esophagus before reaching your stomach, creating a choking risk. If you ever experience chest pain, vomiting, or difficulty swallowing or breathing after taking it, that requires immediate medical attention.
Citrucel is not appropriate for everyone. People with bowel obstruction, fecal impaction, difficulty swallowing, or symptoms suggesting appendicitis should not use it. It’s also contraindicated if you have gastrointestinal ulceration or adhesions, or if you’re experiencing rectal bleeding that hasn’t been evaluated. People on a low-sodium diet should check with a doctor before starting it.
For most people, though, Citrucel is well tolerated. Starting with a smaller dose and gradually increasing over a week or two helps your digestive system adjust. Drinking water throughout the day, not just with your dose, makes the supplement work more effectively and reduces the chance of any initial discomfort.