This isn't a trendy ingredient, psyllium is one of the most clinically studied fibers in existence, with multiple randomized controlled trials confirming it increases stool frequency, improves consistency, and reduces straining compared to placebo.
In one 16-week randomized trial, psyllium was directly compared against a common pharmaceutical stool softener, not just sugar pills.
In a 12-week randomized controlled trial in patients with type 2 diabetes and chronic constipation, psyllium supplementation improved constipation symptoms, reduced body weight, and improved blood glucose and cholesterol levels compared to placebo.