Psyllium fiber when used alone or along with other clinical interventions may modestly reduce LDL cholesterol. There is a wide variation in the dosage and durations used, with clinical studies ranging from 2.4–20.4 grams per day over 2–52 weeks.[1][2][3][4][5][6][7][8]
Psyllium may reduce blood pressure (7–12 grams per day, over 6–8 weeks), triglycerides, and total cholesterol (3–20.4 grams per day, for more than 2 weeks) as well, but the effects are much less consistent.[2][9][5][10][8] However, other studies on these cardiovascular outcomes suggest psyllium is ineffective[1][7][11][12] or more effective as part of another dietary intervention, such as increased protein intake or a healthier diet overall.[13][14][15][16][17] The effectiveness may also vary depending on dose, duration, and participant characteristics (e.g., no apparent health conditions vs. prior health conditions at baseline).