Gear-obsessed editors choose every product we review. We may earn commission if you buy from a link. How we test gear.

This fiber-rich ingredient packs a nutritious punch.

As we are becoming increasingly aware of how essential dietary fiber is for our health, people are trying to figure out ways to consume more of it. This is why a certain fiber supplement infamous for its laxative effects has resurfaced: psyllium.

Psyllium isn’t new, but it seems to be experiencing a resurgence in recipes, such as smoothie bowls and keto-approved bread. Keto and gluten-free bakers love it because it’s a good way to bind baked goods without using flour or drastically altering the taste.

Most notably, psyllium is sky-high in fiber which is why some people use it as a dietary supplement to get what they need. But its unique type of fiber appears to help with a lot more than keeping your bowels running smoothly.

Here’s everything you need to know about this fiber heavyweight and some intel on whether you should consider adding it to your daily diet.

Psyllium (pronounced “silly-um”) is a form of fiber made from the husks (outer coating) of seeds that come from the shrub-like Plantago ovata plant. This plant is primarily grown in a few regions of India. It’s made through mechanical milling or grinding to remove the seed’s outer layer, where the fiber is highly concentrated. Psyllium husk is predominantly a soluble fiber, composed of arabinose and xylose to form arabinoxylan fiber.

As the main ingredient in Metamucil, it is most commonly used as a laxative, but we now know that this non-digestible, water-holding carbohydrate goes beyond sending you to the bathroom.

Psyllium is an easy way to increase your fiber intake. This is especially important as, according to a diet analysis from last year, only 7.4 percent of American adults met the Institute of Medicine’s suggested daily fiber consumption, which is 14 grams of fiber per 1,000 calories consumed.

Fiber remains a nutrient of public health concern, as identified in the 2020-2025 Dietary Guidelines for Americans. “Adding psyllium to the diet works for many Americans to help get the additional 10 to 15 grams per day that they need to add,” says Joanne Slavin, Ph.D., R.D., a professor in the department of food science and nutrition at the University of Minnesota Twin Cities in St. Paul.

A 1-tablespoon serving of finely ground psyllium powder provides about 30 calories and 6 to 7 grams of fiber. The same amount of whole psyllium husks provides a little more than half the calories and fiber.

Gastrointestinal problems are not uncommon among the general public, as well as endurance athletes, which can include bouts of constipation. Though often not discussed, constipation is common and certainly unpleasant GI issue in America. So it’s good to know that the Metamucil ads are true: gel-forming psyllium is an effective soluble fiber for helping alleviate those backed-up moments.

Several studies, including one in the International Journal of Molecular Sciences and another in Alimentary Pharmacology and Therapeutics have indeed demonstrated the efficacy of psyllium husk in making bowel movements easier and relieving constipation. In fact, the soluble fiber in psyllium has been shown to be more effective in dealing with constipation than a popular pharmaceutical stool softener.

“As psyllium makes its way down your digestive tract, it absorbs water in the intestines to form a gel-like structure that adds bulk to the stool which becomes softer and easier to pass,” Slavin tells Runners World. “This can help people return to having regular, more comfortable bowel movements.”

Some non-gel forming fibers like wheat bran add only to the dry mass of stool, which can have a stool-hardening effect and surprisingly make constipation worse. Additionally, pysllium mechanically irritates the gut mucosa, stimulating water and mucous secretion that also contributes to softer stools with more bulk.

On the other end of the bowel health spectrum, psyllium is also effective in treating mild-to-moderate cases of diarrhea. Its liquid holding capacity can help improve the consistency of loose and watery stools. This is good to know if too many sugary foods or a change in diet when traveling has left you running to the bathroom too often.

It’s worth noting that psyllium is minimally fermented in the digestive tract, which means that your gut bacteria produce less gas from it, making it less likely to bring on gas-related side-effects. This also allows it to be a suitable fiber option for runners who are battling irritable bowel syndrome, a common chronic gastrointestinal disorder. In fact, a study in the journal BMJ found 10 grams a day of psyllium for three months reduced symptoms in people with IBS. In this population, non-fermented psyllium can help increase fiber intake with a lower risk for abdominal pain, bloating, and flatulence, compared to what can be experienced with some other fibers like bran.

Just keep in mind that using psyllium in cases of constipation or diarrhea is a method of treating the symptom. Neither of which are caused by a psyllium deficiency. So it’s important to properly address the cause of your digestive woes.

If your cholesterol levels could use some improving, supplementing with psyllium is worth considering. A recent meta-analysis of 28 studies, with a median psyllium dose of 10.2 g/d taken for eight weeks, confirmed the efficacy of this soluble fiber for lowering elevated serum LDL cholesterol levels and other markers associated with heart disease. Plus, evidence suggests the cholesterol-lowering benefit of psyllium is also additive to the effects of statin drugs.

Like oats, products with psyllium are allowed by the Food and Drug Administration to make the health claim that they reduce the risk of cardiovascular disease by lowering cholesterol.

According to Slavin, the viscous soluble fiber in psyllium interferes with the absorption of bile acids in the intestines, which forces the bile acids to be excreted out in the stool. To make up for the lost bile acids, which are critical for digestion and absorption of fats and fat-soluble vitamins, the liver has to use cholesterol from the blood to produce more. In this process, levels of LDL (“bad”) cholesterol are reduced. “That’s good news for your overall heart health,” she says.

According to a 2020 meta-analysis of studies investigating the effect of psyllium husk on blood pressure, taking 10 to 15 grams of psyllium per day significantly lowered blood pressure, which can provide another benefit to heart health. The effect was strongest on people with the highest blood pressure.

While psyllium use can help improve cholesterol and blood pressure numbers, there’s no direct evidence that it actually prevents heart disease. Heart disease is very complicated, and it’s not clear that anything that improves cholesterol levels will automatically halt the development of heart disease for everyone.

Non-cholesterol factors such as smoking and chronic stress can also contribute to heart problems. “And I am not aware of studies that have looked at its effect on blood lipids in healthy athletes with lower cholesterol,” adds Salvin. But it’s worth noting that participants in studies have not typically reported negative side effects when using psyllium so there seems little harm in trying psyllium to help make sure your cholesterol score stays in the safe zone.

As we’ve mentioned, the soluble fiber in psyllium is a form of fiber that is water-soluble, meaning that after you consume it, it draws in water to form a gel-like substance in your digestive tract. This increases the resistance to the flow of chyme, a substance consisting of gastric juices and partly digested food, in the small intestine. This, in turn, slows the breakdown of carbohydrates by digestive enzymes and thereby delaying the release of sugar into the bloodstream following meals. “We have good evidence this viscous quality of psyllium can help control the glycemic response to a diet,” says Slavin.

To back that point, some research suggests that psyllium may help people with type 2 diabetes keep their blood sugar more steady and controlled throughout the day. Specifically, researchers have found that taking psyllium before meals can significantly improve fasting blood glucose (sugar) in those with type 2 diabetes.

In an American Journal of Clinical Nutrition study involving 35 randomized controlled clinical studies that spanned three decades and three continents, psyllium (mean 10 g/d, taken in divided doses before meals) improved glycemic control in those with pre-diabetes and those being treated for type 2 diabetes. There was no significant effect on fasting blood glucose in healthy subjects with normal blood glucose control. This sugar-regulating benefit is not overly potent but appears reliable, as long as psyllium is taken regularly.

Though keeping blood sugar under control regularly is key for people with diabetes and pre-diabetes it also could be beneficial for everyone including fit runners since maintaining balanced blood sugar can be helpful in regulating energy levels, lowering cravings and hunger, reducing unwanted weight gain and, yes, lowering the risk of developing diabetes down the road.

But again, poor blood sugar control is not caused by a psyllium deficiency any more than constipation is. Ideally, someone would address the reasons for their high blood sugar numbers (by cutting back many refined or sugary carbs, for example) instead of just relying on a supplement to deal with the problem.

Psyllium husk swells to create a jellylike mass when is mixed with any fluids, and because of this, it adds bulk to your diet and reduces the speed of digestion, helping keep you satiated. This boost in feelings of fullness could help people trim some calories from their diet through better portion control and, in turn, shed a few pounds. Although the weight loss benefits of adding psyllium to the diet have been a mixed bag in research, with some studies showing a positive impact on body weight reduction in people who are overweight, while other research doesn’t show a significant effect.

Slavin says splitting up the psyllium dose throughout the day will have the biggest impact on regulating hunger and energy intake, especially if taken 15 to 30 minutes before meals.

But if you are burning a ton of calories through your workouts you may not necessarily want to suppress your appetite as this can lead to underfueling, which can hinder your fitness gains and even health. In these cases, taking psyllium further away from meals may be helpful so as not to keep you from eating enough to support your training.

According to Salvin, “psyllium is generally safe to use, but gradually introducing smaller amounts to your diet helps to make your body more comfortable with it and limit any possible unpleasant GI symptoms.” And whenever you are going big on dietary fiber she says to make sure you’re drinking plenty of water to improve tolerance.

Psyllium may also impact certain medications including those involved in blood sugar management, so always check with your doctor before taking it if you are using prescription drugs. It’s advisable not to consume too much psyllium before a run to limit the risk for stomach woes.

A general guideline is to take about 1 tablespoon (5 grams) of psyllium powder in cup of liquid 15 to 30 minutes before a meal. Drink quickly as otherwise it can be difficult to swallow as the mixture will thicken almost immediately.

If you’re new to psyllium, Salvin recommends starting with a serving of about 3 grams (½ to 1 teaspoon) and working your way up from there. Going over these amounts—and not consuming it with enough water—may lead to GI distress, so take it slow and see how you feel.

Finely ground psyllium powder is most easily incorporated into the diet. It’s also available in capsules, granules (small flakes), and wafers. Psyllium husk flakes have a grainier texture than the powder when mixed with fluids. (Amazon is a good the best place to buy psyllium powder or try the brand, Bellway.)

It can also be blended into smoothies, mixed into oatmeal and yogurt, incorporated into pancakes and muffin batter (you’ll need to add extra liquid), and used in soups and stews as a natural thickener. Psyllium husk can be used to replace breadcrumbs in meatloaf and hamburger patties to bolster fiber numbers. You can even smear some nut butter on psyllium wafers for a snack.

When psyllium husk is mixed with water and is allowed to sit for a few minutes, it develops a thick, mucilage-like consistency and this “gel” can act as a binder in baked goods and can be used as a replacement for eggs. To replace eggs, use this formula: ¼ cup water + ½ teaspoon psyllium powder = 1 egg. For recipes, 4 teaspoons of whole psyllium husk is about equal to 3 teaspoons of psyllium powder.

Psyllium is a great source of fiber and provides a handful of important benefits, as noted above. Remember, however, that supplements are just that—a supplement to a healthful diet. Eating whole foods, full of fiber-rich foods like fruits, vegetables and legumes, should be your first line of defense for staying healthy, with psyllium being viewed as a nice add-on.