What Is Psyllium Husk and Should You Be Taking It? A Dietitian Explains

Psyllium husk is a fiber powerhouse that can support your gut health — and overall health. It’s well-studied as a remedy for both constipation and diarrhea. And it may help reduce the risk of heart disease by lowering cholesterol, blood sugar, and blood pressure levels.

Read on to learn about the health benefits of psyllium husk, and whether it may be right for you. 

What is psyllium husk fiber?

You may not be familiar with the term psyllium husk fiber. But you’ve likely heard of Metamucil. Psyllium husk is the type of fiber used in Metamucil supplements. 

Psyllium comes from Plantago ovata, a flowering plant. First, psyllium seeds are extracted from plantago using hot water. Then the husks are removed from the seeds in a centrifuge (a fast spinning machine). Psyllium husks can be used whole, but more often they are ground into a fine powder.

Psyllium husk is popular as a dietary supplement to increase fiber in the diet. Usually, people take psyllium husk fiber by mixing the ground powder into water and drinking it. But psyllium husk is also available in capsule and gummy forms. As a food ingredient, whole or ground psyllium is sometimes added to cereals and baked goods to boost their fiber content. 

Psyllium husk nutrition 

One teaspoon (5 g) of psyllium husk powder contains:

• 30 calories

• 4 g carbohydrate

• 0 g fat

• 4 g fiber

• 0 g protein

• 1% daily value (DV) iron

• 3% DV calcium

Psyllium husk isn’t a significant source of any other vitamins or minerals.

What are psyllium husk fiber supplements’ benefits for health?

Psyllium husk is prized for its high fiber content — it’s about 86% fiber by weight. The fiber in psyllium husk is linked to many health benefits for the gut and beyond.  

Relieves constipation and diarrhea

Psyllium husk helps with constipation by softening stool and making it easier to poop. It usually takes a few days for psyllium to work. So it’s different from a laxative that provides immediate relief. Psyllium husk works like a sponge by trapping water in the intestine. This softens stool, and can help keep you regular over time.

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On the flipside, psyllium can also help with diarrhea (loose, watery stools). You may wonder how the same supplement can help both constipation and diarrhea, since they seem like opposite conditions. By absorbing water in the intestines, psyllium helps to bulk up loose stools. 

So, by softening hard stools (constipation), and bulking up loose stools (diarrhea), psyllium husk powder can help with both conditions. Because of this, psyllium is often recommended for people with:

• Irritable bowel syndrome (IBS), which can cause alternating bouts of constipation and diarrhea 

• Hemorrhoids

• Inflammatory bowel conditions such as Crohn’s disease and colitis 

Acts as a prebiotic

Psyllium is a nondigestible fiber that acts as a prebiotic. Prebiotics feed the healthy bacteria in your gut. This supports a healthy microbiome. 

But prebiotics affect more than your gut health. Once prebiotics reach the large intestine, they are fermented. This creates short-chain fatty acids (SCFAs) that travel throughout your body and may benefit your health in many ways, including:

• Supporting immune health

• Improving calcium absorption 

• Fighting intestinal inflammation

Helps lower cholesterol levels

Psyllium forms a gel as it moves through the digestive system. This gel helps trap bile acids and cholesterol and eliminate it as waste (poop). This is how psyllium husk helps lower “bad” LDL cholesterol levels. Studies show that consuming about 10 g of psyllium per day may lower cholesterol levels by up to 20%. 

Helps manage blood sugar

Studies show that 10 g per day of psyllium for several weeks may help regulate blood sugar and improve hemoglobin A1c. This is a measure of your average blood sugar over 2 to 3 months. For this reason, psyllium is sometimes recommended for people with Type 2 diabetes. 

Researchers believe that the gel in psyllium helps slow down sugar’s absorption in the digestive tract. The trapped sugars are slowly absorbed into the blood over time, instead of quickly. This helps prevent blood sugar spikes and makes it easier to maintain stable blood sugar levels. 

Helps reduce blood pressure

Doses of 10 g to 15 g of psyllium per day may help reduce blood pressure levels in people with hypertension. Studies show that psyllium fiber helps reduce both systolic and diastolic blood pressure (the top and bottom numbers) when supplements are taken for at least 8 weeks. It’s not clear exactly how this works, so more research is needed. 

Supports weight management

Drinking psyllium powder mixed with water may support weight loss in people with obesity. Taking about 10 g over the course of the day — right before meals — was shown to be effective. This is likely because psyllium increases satiety (the feeling of fullness), and slows down digestion, so you eat less at meals. 

Reduces the risk of colon cancer

Psyllium fiber may help decrease your risk of colon cancer by:

• Improving some common risk factors for cancer, such as blood sugar and maintaining a comfortable body weight

• Helping to support a healthy gut microbiome, which can use fiber to make short-chain fatty acids with anticancer properties

• Bulking up stool, which moves it through the gut more quickly. This decreases the amount of time potential carcinogens (cancer-causing chemicals) remain in the intestine.

Potential downsides

Taking too much fiber — or increasing fiber intake too quickly — can cause side effects, such as:

• Gas

• Nausea

• Bloating 

If you have severe stomach pain, bloody stools, or constipation for more than a week, stop using psyllium and talk with a healthcare professional.   

A small number of people have a psyllium allergy, and may experience hives, difficulty breathing, or swelling of the lips, tongue, or throat. In this case, discontinue use and get medical attention. But this is rare. 

How often can you take psyllium husk fiber?

It can be safe to take psyllium husk fiber supplements daily. But it’s important to talk with a trusted healthcare professional before starting psyllium husk fiber if you have gastrointestinal problems. They can help determine the best dose for you, and how long you should take it for. 

Be sure to wait 2 hours between taking oral medications and psyllium. This is because psyllium can affect how well other medications work.

Tips for taking psyllium husk supplements

It’s important to take it with fluids. Psyllium works by pulling water into the intestines, so there needs to be enough water available to help it do its job. 

Psyllium powder is sold plain or sweetened (with sugar or artificial sweetener). Different manufacturers recommend different doses. And a healthcare professional may suggest a specific dose for you. Usually, it’s best to start with a small dose of about ½ tsp, and increase it over time. 

Most people mix psyllium powder with a full glass (8 oz) of water. But you can mix it with any drink. Note that psyllium doesn’t dissolve fully in liquid. So it’s normal for the beverage to be cloudy with specks of detectable psyllium husk. Some people describe it as gritty, sandy, or earthy. 

If you don’t want to drink psyllium husk powder in liquid, you can try psyllium capsules. But this is a less efficient supplement. You’d need to take several capsules to get the same amount of fiber in 1 tbsp of psyllium powder. If you do take capsules, be sure to pair them with plenty of water.

Some packaged foods contain psyllium. Examples are Bran Buds cereal and Metamucil Fiber Thins cookies. But you won’t always get very much psyllium by eating standard servings of these foods. 

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Written by:

Cara Rosenbloom, RD

Cara Rosenbloom, RD, has been a registered dietitian for 22 years. She began her career working as a dietitian at Toronto's Hospital for Sick Children (SickKids).

Edited by:

Meredith Hoffa

Meredith Hoffa is a senior health editor at GoodRx, where she leads journalists and clinicians covering various well-being topics, particularly in diet and nutrition.

Reviewed by:

Mandy Armitage, MD

Mandy Armitage, MD, has combined her interests in clinical medicine with her passion for education and content development for many years. She served as medical director for the health technology companies HealthLoop (now Get Well) and Doximity.

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