Blond psyllium (Plantago ovata) is a soluble fiber commonly used for digestive health. Its application in "leaky gut syndrome"—a controversial and not universally recognized medical condition—has been explored primarily due to its effects on gut barrier function and intestinal health. Scientific evidence for psyllium specifically treating or supporting "leaky gut syndrome" is limited. Some studies have shown that psyllium supplementation can improve gut mucosal integrity and increase the production of short-chain fatty acids (such as butyrate), which are important for maintaining the intestinal barrier. Animal and in vitro studies suggest that soluble fibers like psyllium may reduce intestinal permeability by promoting the growth of beneficial gut bacteria and supporting mucus production. However, robust clinical trials in humans with "leaky gut syndrome" are lacking.

Most human studies focus on psyllium’s benefits for constipation, irritable bowel syndrome, or cholesterol management, rather than directly on intestinal permeability. While the theoretical basis for its use in supporting gut barrier function exists, current scientific validation for its effectiveness specifically in "leaky gut syndrome" is weak, leading to a moderate-low evidence rating. More targeted research is needed to confirm its role in treating or supporting this condition.