Psyllium husk — a cheap fiber supplement that aids weight loss, curbs cravings, and eases indigestion — is booming in the wellness world. Here's how it works.

• Psyllium husk, also known as ispaghula, is a fiber commonly used to promote digestion.
• Evidence shows that psyllium can relieve constipation and diarrhea, and may lower glycemic response.

A fiber that's been used for centuries is gaining popularity in the US as a anti-diarrheal agent, a constipation buster, and a cheap weight loss supplement.

Psyllium husk is a powder derived from the seeds of Plantago ovata, a shrub native to South Asia. It can be stirred into drinks and baked into foods.

While this ingredient has been used for generations across the world, the New York Times' Priya Krishna reports that it is newly becoming a wellness trend in the United States — with over 200 new psyllium products released in the US between 2018 and 2022, according to market research from the company Mintel.

Despite its unassuming appearance, psyllium husk is a multidimensional fiber that is easily accessible (a 450-gram bag could cost as little as $10, or roughly 20 cents per 10-gram serving).

Crucially, as the Times reported, it meets the demand of an "Ozempic generation" that is hungry for cheap ways to lose weight by curbing cravings. (Hence Mumsnet dubbing psyllium husks "the poor man's Ozempic.")

Psyllium husk eases digestion by solidifying stool

Psyllium is a bulk forming mostly soluble fiber, in other words it can help solidify and pass stools — improving digestion.

Psyllium works by rounding up digested contents in the small intestine into one solid stool, leading to a reduction in constipation. It can also soak up excess water, alleviating diarrhea. The "end product," Medical News Today notes, is "bigger and easier to pass stools."

One 1998 study found that taking just 5.1 grams of psyllium twice a day for two weeks significantly increased the total number of bowel movements in 170 people who have chronic constipation. In 2000, a small study of 30 people undergoing radiation therapy for cancer found that psyllium husk significantly decreased diarrhea.

Slowing digestion helps to control blood sugar levels

Taking 10.2 grams of psyllium could also control the body's glycemic response to a meal, by lowering insulin and blood sugar levels.

To work best, Medical News Today recommends that you take psyllium with your meal to help slow the digestion of food, thereby maximizing its benefits on blood sugar levels.

Psyllium might help you feel fuller initially, but could cause you to binge eat later

The weight loss benefits of psyllium husks are more dubious.

According to one small 2016 study, 10.2 grams of psyllium before breakfast led to significant increases in the feelings of fullness, and helped curb hunger and desire to eat between meals compared to a placebo.

But a 2020 review didn't find that psyllium had any effect on BMI, body weight, or waist circumference.

Dr. Pieter Cohen, an internist at Cambridge Health Alliance in Massachusetts, told New York Times that psyllium isn't a "wonder drug" and that he advises against using psyllium as an appetite suppressant.

While it may work temporarily — by making you too full to snack — he says that psyllium "revs up our appetite a few hours later because we didn't get any calories."

The "best way" to get fiber "is through real foods: fruits and vegetables," Cohen told the Times.

He also recommends looking for products that are absent of added sweeteners or flavorings, which can be caloric.

Additionally, he encourages people to take psyllium with plenty of water, as too much fiber and too little water can lead to constipation.