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Last updated on June 22, 2017

The Best Fiber Supplement

Fiber sources clinically proven to benefit your health
The 30-Second Review

Fiber supplements boast health claims that range from normalizing blood sugar to improving digestion, but these promises aren't always well-researched. The best fiber supplement should be clinically proven to deliver on its claims. After speaking with dietitians and nutritional researchers and reviewing the scientific literature, one type of fiber came out on top: psyllium fiber. Our top picks — two psyllium powders and one capsule — keep additives to a minimum, were more palatable than other formulas, and have ample research to support their benefits.

Best Overall

Contains nothing but finely ground psyllium husk. Like all fiber powders, it must be mixed with water or another liquid before consuming, forming a gel-like texture our testers weren't wild about. But we found Yerba Prima smoother and easier to swallow than other formulas.

Others to Consider

A flavored powder that reminded us of an orange smoothie once mixed with water. The tradeoff? It has more sugar (8 grams) than fiber (3 grams) per serving.

Yerba Prima Psyllium Husks Caps
A capsule alternative to powders. Because fiber is bulky, just know you'll have to swallow a lot of pills for an effective dose.

The Best Fiber Supplement

The average American only consumes about 15 grams of fiber per day, falling well short of the commonly recommended daily fiber intake of 25 grams for women and 38 grams for men. A serious dietary workhorse, fiber is responsible for keeping you full after eating and bringing a certain digestive regularity to your day. But if you’re planning to add a fiber supplement to your diet, it’s important to be aware that fiber can come from many sources — and some are more beneficial than others. Psyllium stood out time and again as the best fiber supplement on the market.

Yerba Prima Psyllium Husks Powder was our overall top pick. Easy to dissolve and relatively palatable, this product consists of nothing but pure psyllium husk, ground to a consistency that’s a little smoother and easier to swallow than the other powders we tried. For something a little tastier, try Metamucil MultiHealth Fiber Powder — an orange-flavored powder that we found surprisingly delicious. Unfortunately, the tastiness comes at a cost: Each serving delivers more sugar than fiber, with over 2 grams of sugar for every gram of fiber. If you can’t stomach a liquid formula at all, you can also try Yerba Prima Psyllium Husks Caps, which contain nothing but powdered psyllium fiber in a gelatin casing. To hit widely recommended fiber supplement dosages, however, you’ll need to down 18 capsules a day.

Our Picks for Best Fiber Supplement

Best Overall

Yerba Prima Psyllium Husk Powder Nothing but finely ground psyllium husk powder. Dissolves quickly in liquid.

This straightforward, one-ingredient supplement supports heart health, satiety, blood sugar regulation, and digestive benefits, with a texture testers preferred over the other powdered mixes we tried. Inside the plastic jar, you’ll find finely ground psyllium husk, a fluffy brown powder that testers said smelled like “oatmeal” and “hay.” There’s nothing else on the ingredient list: no fillers, no additives — just pure psyllium powder.

One heaping teaspoon delivers 4.5 grams of fiber. Just be aware that once mixed with water, the powder immediately begins to gel — and becomes more viscous the longer it sits. After three minutes, the texture reminded us of runny applesauce, and our main takeaway post-testing was that you should drink it quickly. That said, Yerba Prima gave us a wider drinkability window than some contenders. Species Fiberlyze turned into a solid mass within 30 seconds of mixing, with one tester reporting that it resembled cement — and turned the glass upside down to prove it.

Yerba Prima’s applesauce-like texture (left) was more appealing to us than the thicker, grainier texture of other contenders, like Species Fiberlyze (right).

Most of our testers also preferred the texture of Yerba Prima’s ground psyllium husks over “whole husk” products like Colon Cleanse Everyday Fiber, which had a grainy texture we found off-putting in a beverage. Yerba Prima doesn’t taste like much — it has faintly herbal undertones that none of our testers took issue with. Like most psyllium powders, you can also mix it with more than just water. The packaging suggests trying juice, milk, soy, or rice drink, and we could also see psyllium powder being an easy addition to a smoothie. A 12-ounce bottle retails for $9.

Others to Consider

Metamucil MultiHealth Fiber Powder A flavored powder that reminded us pleasantly of an orange smoothie but contains a lot of sugar.

If you need a spoonful (or three) of sugar to make your fiber go down, Metamucil MultiHealth Fiber received one of the highest scores on our taste-test. It’s an orange-flavored powder that looks like fruit punch mix and has a texture reminiscent of a smoothie once you add water. The end result was also surprisingly tasty, with one tester reporting, “This reminds me of Tang.”

But we were unable to give Metamucil MultiHealth our top spot due to the sheer amount of sugar it contains. Sucrose appears first on the ingredient list, meaning this supplement has more sugar than fiber. A 1-tablespoon serving gives you 3 grams of dietary fiber — and 8 grams of sugar. (An Oreo has about 4.7 grams of sugar, by comparison.)

All that being said, if the only way you’re going to keep taking a fiber supplement is if it tastes better, then Metamucil MultiHealth Fiber is our pick. A 48-ounce tub retails for about $17.

What about sugar-free Metamucil?

Metamucil does offer a Smooth Sugar Free Fiber Powder, but the name is misleading. The formula doesn’t contain table sugar, but the second ingredient on the list is maltodextrin — a sweetener with a glycemic index similar to sucrose. In other words, maltodextrin will have approximately the same effect on your blood sugar levels as regular sucrose.

Yerba Prima Psyllium Husks Caps Gelatin capsules that contain nothing but psyllium. An alternative to powder, but you'll have to swallow a lot of them.

If you have strong objections to a thick, goopy texture, you can also try fiber capsules. The drawback? Fiber is bulky, and there’s only so much you can fit in a single capsule. If you’re aiming for the widely recommended 10-gram dose, be prepared to swallow a lot of pills.

Yerba Prima Psyllium Husks Caps stood out because they had a slightly higher psyllium content than the other capsules we tested, at roughly 0.55 gram per pill, versus the 0.4 gram offered by Metamucil’s MultiHealth Capsules, or Thompson Psyllium Husks’ 0.5 gram. It’s a slight increase, but if you’re aiming for 10 grams a day, it will save you from swallowing an additional three to seven pills. (Although you’ll still need to swallow eighteen to hit that recommended dosage.) You get 180 capsules per $8 bottle.

We also appreciated the transparency of Yerba Prima’s label, which spells out exactly how many grams of soluble and insoluble fiber you’re getting, in addition to calling out trace elements like calcium and potassium. Thompson Psyllium Husk’s label, by contrast, includes no information except milligrams of psyllium.

Did You Know?

Getting your fiber from food is still best.

The National Fiber Council recommends that consumers rely on food-based fiber sources whenever possible. Our experts agreed. “I recommend people get their fiber from food first because along with the fiber, they also get vitamins, minerals, powerful plant compounds, water, and electrolytes,” said registered dietitian Elaine Magee, MPH, RD, a wellness corporate dietitian for Albertsons Companies. “Sometimes with certain health conditions or living situations, people just can’t get all the fiber they need from food. This is when a fiber supplement may be helpful.”

If you want to make changes to your diet, but you’re not sure where to start, Magee offered these guidelines: “By eating about 3 cups of veggies and 2 cups of fruit a day, you’ll consume roughly 15 grams of fiber. A handful of nuts will add 3.5 grams. Three servings of whole grains a day adds approximately 9-15 grams.”

If you’re looking for specific recommendations, the Mayo Clinic suggests artichokes, green peas, and broccoli as good vegetable-based fiber sources, and raspberries, pears, and apples if you prefer fruits. Lentils and beans of all varieties are also chock-full of fiber.

Fiber in baked goods might not be as potent.

Many baked goods, like breads, snack bars, and even some fiber supplements — like Metamucil’s Multi-Grain Fiber Wafers — use beta-glucan from oats as a fiber source. Beta-glucan offers many of the same health benefits as psyllium (though clinical research suggests it lacks the ability to normalize bowel movements). But notably, research suggests beta-glucan is more fragile than psyllium: Its ability to lower cholesterol may be reduced when it’s baked or exposed to high heat and pressure. The jury is still out on exactly how much the cooking process impacts oat fiber, but it’s one more point in favor of psyllium in the meantime.

The health claims that fiber supplements are allowed to make are changing.

The Food and Drug Administration is beginning to scrutinize less-effective fiber sources. A rule change to the Nutritional Labeling and Education Act (NLEA) issued in 2016 will require fiber supplement manufacturers to prove the health benefits of their sources of fiber in order to print health claims on labels. That rule is likely to affect much of the market, including well-known brands with “fiber” in their name, such as Benefiber, that use non-psyllium formulas but still make broad claims about the efficacy of their products. “By July 2018, these fiber types have to prove their health benefits,” McRorie told us.

The Best Fiber Supplement Summed Up