What Dietitians and Doctors Want You to Know About Fiber Supplements

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You may have heard that fiber is important for better poops. But fiber has so many more benefits. According to Fazia Mir, M.D., a gastroenterologist and expert for the American Gastroenterological Association, fiber can help lower cholesterol, support weight loss by bringing on early satiety, avoiding constipation, decreasing the risk for diverticular disease, and preventing glucose and insulin spikes in the blood. When you don’t have access to good sources of fiber, the best fiber supplement may help.

“Dietary fiber is a super nutrient primarily found in high-fiber foods like whole grains, legumes, fruits, vegetables, nuts and seeds,” says Jessie Anderson, R.D., registered dietician at Top Nutrition Coaching. “However, the majority of Americans fall short of the Recommended Dietary Allowance (RDA) for dietary fiber. The RDA for men equates to about 38 grams per day and for females, 25 grams per day.”

Meet the experts: Jessie Anderson, R.D., C.S.S.D., L.D., ACSM EP-C at Top Nutrition Coaching; Samantha Cassetty, M.S., R.D., food and nutrition expert; Heather Mangieri, R.D.N., a sports and wellness dietitian; Fazia Mir, M.D., a gastroenterologist and expert for the American Gastroenterological Association; Lance Uradomo, M.D., M.P.H, gastroenterologist at City of Hope.

Dr. Mir, Anderson, and Heather Mangieri, R.D.N., a sports and wellness dietitian, recommend first and foremost to get the fiber you need through food. “However, people suffering from constipation, diarrhea, irritable bowel syndrome (IBS), or other medical conditions that are not able to get enough fiber from foods may benefit from a supplement,” Mangieri says.

“Dietary supplements are not meant to be used indefinitely,” Anderson notes. “However, dietary fiber supplements may be resourceful in assisting a consumer in helping to meet their RDA for dietary fiber while working to enhance the overall nutritional quality of their current dietary regimen.”

Ahead, find the best fiber supplements for constipation, IBS, and an overall healthier gut.

Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.

FiberMend Prebiotic Fiber Powder

Anderson calls the Thorne FiberMend dietary supplement powder her “favorite.” She says, “Thorne has a wonderful fiber supplement containing a mixture of soluble fiber (6 grams), insoluble fiber, and polyphenols. It’s also gluten-free, soy-free, and dairy-free.”

Simply mix one scoop into 8 to 10 ounces of your favorite beverage or as recommended by your primary healthcare physician. Reviewers like that the powder is easy to use, has little to no taste, and works quickly. Some users, however, are mixed on whether or not the powder dissolves easily (which is a common issue for fiber powders).

What a reviewer says: “I use this in my morning coffee to add extra fiber to my diet. It dissolves easily and does change the flavor of the coffee.”

Psyllium Husk Powder

According to Samantha Cassetty, M.S., R.D., food and nutrition expert, studies have shown that psyllium fiber supplements may help lower cholesterol and lead to better glucose management. “This type of fiber may also help normalize your bowel habits. So, if you have constipation, it can help soften stool and make it easier to pass, and if you have diarrhea, it can help create firm stool,” she adds. Cassetty recommends this pick from NOW Foods because it’s so versatile.

Dr. Mir also recommends psyllium husk, “as it has both soluble and insoluble fiber.” Simply mix one tablespoon into at least 12 ounces of water or juice and consume right away.

What a reviewer says: “My dietitian advised me to use this product because it is soluble fiber which is the part of the fiber that helps constipation and it is not a capsule which frequently do not seem to work. I take it as directed in the middle of the afternoon. I tolerate the flavor just fine and take it with water. Some may prefer some type of flavor enhancer. I love this stuff cause it works so well for me.

Dr. Formulated Organic Fiber Supplement Powder

Anderson also recommends the Dr. Formulated Organic Fiber from Garden of Life. She points out that it contains 4 grams of soluble fiber and 1 gram of insoluble fiber per serving, plus it’s psyllium, gluten and dairy free.

The prebiotic fiber contains a superfood blend of acacias, orange peels, baobab fruit, apple peels and cranberries. The label advises users to add one tablespoon of the powder to your preferred beverage.

Note that while the powder is advertised as tasteless, several reviewers noticed a slight citrus taste and smell. However, most didn’t find the taste offensive.

What a reviewer says: “This product is the only thing that has worked for me. It is completely life-changing, buy it. [Just note that] it doesn’t mix with water easily. You must use a blender bottle or it just won’t dissolve.”

Daily Prebiotic Fiber

Another recommendation by Anderson, the Bio.me Daily Prebiotic Fiber contains 7 grams of soluble fiber per serving. According to the brand, this powder combines two clinically-researched prebiotics. Plant-derived resistant potato starch and hydrolyzed guar gum (PHGG) in the formula help promote a healthier gut.

A lot of fiber powders are advertised as tasteless, but in most cases, you’ll likely find a hint of flavor in these powders. However, several reviewers say that this powder by Bio.me is truly “flavorless.” While subjective, the common comment is significant to note.

What a reviewer says: “It mixes into my coffee pretty effortlessly and it’s completely flavorless. I was worried it was going to give my coffee a grainy or chalky texture, but it didn’t. I can’t taste this at all so it’s been a great addition.”

Daily Prebiotic Fiber Supplement Powder

If you are looking to increase daily fiber intake for all members of the family, Benefiber says that their fiber powder is safe for kids and teens. Anderson also recommends the Benefiber supplement, saying it contains 3 grams of soluble fiber per serving, plus it’s gluten-free.

You can mix the fiber powder directly into water, juice, smoothies, or even soft food. Most reviewers say that the powder dissolves easily. We like that the fiber powder is low-calorie and sugar-free. It also goes on sale often—at the time of publication, you could buy one, get one for 50% off at CVS.

What a reviewer says: “There’s no taste and it does not change the texture of your drink. This is now a daily staple of mine as someone who has a hard time finding fiber elsewhere since I don’t like too many veggies.”

Fiber Well Gummies

If powder or hard capsules are not your thing, Vitafusion makes fruit-flavored gummies with prebiotic fiber. Peach, strawberry and blackberry flavors give off a pleasant taste, and the brand promises no gluten or added sugars.

Take two gummies per day to get 5 grams of fiber. You get 90 gummies in one bottle. Just note that some reviewers complain about the gummies being slightly hard to chew or clumping together in warmer temperatures.

What a reviewer says: “I eat [on] keto and these help me get my fiber in. I’ve been using them for a long time. They taste good and they work.”

Psyllium Fiber Supplement

Metamucil is a common brand that comes to mind when it comes to fiber supplements since it is affordable and easy to find at most drugstores and supermarkets.

The brand claims that this 4-in-1 fiber powder helps support healthy blood sugar levels and appetite control while aiding in lowering cholesterol. Because it is sugar-free, some reviewers say that it works well for those with diabetes. Note that this is a user-based claim—and it is encouraged to check with your healthcare provider or dietitian for your specific needs and concerns.

For best results, follow directions and mix one teaspoon into 8 ounces of your beverage of choice, three times per day.

What a reviewer says: “It helps me feel lighter and more energetic throughout the day. The fiber blend is gentle yet effective, promoting digestive health without discomfort. I appreciate how easy it is to mix into my favorite beverages, and the orange flavor is quite pleasant. Since starting with Metamucil, I’ve noticed a significant improvement in my overall well-being and regularity.”

PureLean Fiber

Adequate fiber in your diet may help with weight loss. It plays a small part, but experts have shared with us that fiber can slow the speed of the digestion process, making you feel less hungry. This pick from Pure Encapsulations claims to promote a healthy gut and support weight management. Some reviewers say the formula helps keep them feeling full for longer.

Directions say to mix two scoops into your preferred beverage, followed by drinking plenty of water. Each serving includes a minimum of 6 grams of fiber.

What a reviewer says: “I have been using this now for three months, and it is by far the best product out there. I will mix in with my overnight oats or smoothies.”

How to choose the best fiber supplements

Start by looking at the Supplements Facts label to make sure that the product is coming from a reputable manufacturer. “It is encouraged to seek out dietary supplements with a third-party certification which tests for purity, potency, quality, safety, effectiveness of the product: NSF-certified for Sport, Informed Sport, BSCG, and USP, are a few examples,” Anderson says. As many dietary fiber supplements lack third-party certification on the market, Anderson advises seeking guidance from a healthcare professional before purchasing and using a new supplement.

Anderson also stresses that when choosing a dietary fiber supplement, it is important to keep in mind the goal for use. “If you’re looking to simply add a little more fiber to your daily nutrition, it is recommended to seek out a supplement containing 3 g fiber per serving (coming from either or both—soluble and insoluble fiber),” she explains. However, she adds that those experiencing constipation should consider taking 6 to 7 grams of insoluble fiber per day, while those with diarrhea or seeking lower cholesterol and/or blood sugar regulation should consider taking 6 to 7 grams of soluble fiber per day.

Finally, when buying a fiber supplement, Dr. Mir says to keep in mind that it doesn’t contain flavors or artificial sweeteners as that may worsen the bloating. Similarly, Lance Uradomo, M.D., M.P.H., a gastroenterologist at City of Hope, warns that people with celiac disease or gluten sensitivity should be aware that some supplements contain wheat and gluten.

Things to keep in mind when using fiber supplements

✔️ Start slow: “It’s important to be mindful of how much added fiber you consume,” Mangieri says, adding that incremental introduction is crucial. “Increasing dietary fiber too quickly can lead to side effects like gas, bloating, and cramps.”

Dr. Mir agrees, saying, “I do caution my female and male patients with irritable bowel syndrome to start slow to avoid the risk of bloating.”

✔️ Talk to your doctor: Discuss your plan to start a fiber supplement with your doctor or a registered dietician, who can offer professional guidance. “Talk to your doctor about digestive problems you may be experiencing, such as constipation or irregular bowel movements,” Dr. Uradomo says. “Also, fiber supplements can sometimes interfere with prescription medications, which is another reason to talk to your doctor before taking them.”

✔️ Check the label: Like Anderson mentioned, look for a product that comes from a reputable manufacturer. “The product should list the fiber source on the package and the company should be able to answer your questions,” Mangieri adds.

✔️ Hydrate regularly. “Always chase the fiber that you intake with water so as not to worsen constipation,” Dr. Mir says.

✔️ Expect possible gas or cramping. Dr. Uradomo warns that some supplements may contain ingredients that can cause gas or cramping.

Dietary fiber benefits

Our experts shared earlier that dietary fiber is important for digestive health, metabolism, and cardiovascular health and may help reduce the risk for certain cancers, like colorectal and breast cancer. Our experts break down the many benefits of a high-fiber diet below, which may include:

✔️ Better digestive health: A high-fiber diet can help regulate bowel movement, Anderson says.

✔️ Blood sugar management: “Dietary fiber can help prevent glucose and insulin spikes in the blood,” says Dr. Mir.

✔️ Gut function optimization: Daily fiber intake may reduce the risk for certain cancers and digestive disease states, including diverticulitis and the development of hemorrhoids. “In fact, there is evidence that consuming fiber is associated with a lower risk of dying from any cause,” Dr. Uradomo says.

✔️ Cholesterol lowering effect: “Soluble fiber targets ‘bad’ cholesterol while aiding a healthy blood pressure,” Anderson explains.

✔️ Anti-inflammatory benefits: According to Anderson, fiber supports a healthy immune system while reducing systemic inflammation, promoting optimization of all regulatory functions.

✔️ Metabolic health: Because fiber aids blood glucose regulation by slowing the absorption of sugar, it may also help reduce the risk of developing (and can help) type 2 diabetes, says Anderson.

✔️ Supports a healthy weight: “Fiber increases feelings of satiety and fullness at and between meals, helping to moderate portion sizes and curb cravings,” Anderson says.

Are fiber pills better than fiber powder?

This depends on your personal goals with fiber intake. “Fiber powder is better because pills can get stuck in the esophagus if patients don’t swallow with enough water,” Dr. Mir says.

Anderson adds that fiber powder can be appealing and convenient since you can add it to water, juice, or a smoothie. “Plus, dietary fiber supplements in the form of powder oftentimes contain a much more potent dose of fiber per serving compared to capsule form,” she says.

On the other hand, dietary fiber capsules may be beneficial to those looking to add a small amount of fiber to their diet while enhancing overall food intake, Anderson continues. “However, it should be noted not all dietary fiber supplements are the same and both powders and capsule forms may contain ingredients that are not well tolerated by specific individuals (like wheat or corn).”

What is the difference between soluble and insoluble fiber?

Soluble fiber dissolves in water which allows it to form a gel-like texture, says Anderson. “Soluble fiber slows down digestion and allows for nutrients to be absorbed. It is commonly known for its role in aiding diarrhea while lowering ‘bad’ (LDL) cholesterol and regulating blood sugar levels.”

Insoluble fiber promotes gastric motility to support the passing of materials through the digestive system, resulting in a bowel movement. “Insoluble fiber may assist those experiencing constipation or bowel movement irregularities,” Anderson explains.

How we chose the best fiber supplements

We tapped Jessie Anderson, R.D., C.S.S.D., L.D., ACSM EP-C at Top Nutrition Coaching; Samantha Cassetty, M.S., R.D., food and nutrition expert; Fazia Mir, M.D., a gastroenterologist and expert for the American Gastroenterological Association; Lance Uradomo, M.D., M.P.H., gastroenterologist at City of Hope. and Heather Mangieri, R.D.N., a sports and wellness dietitian. Cassetty provided the recommendation from NOW Foods, while Anderson recommended the picks from Thorne, Garden of Life, Bio.me, and Benefiber.

Additionally, we poured through product descriptions, labels and user reviews to complete this list.

Why trust us

For more than 70 years, Prevention has been a leading provider of trustworthy health information, empowering readers with practical strategies to improve their physical, mental, and emotional well-being. Our editors interview medical experts to help guide our health-focused product selections. Additionally, Prevention also examines hundreds of reviews—and often conducts personal testing done by our staff—to help you make informed decisions.

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