Clinical studies have shown that Metamucil can help reduce cholesterol levels in people with mild to moderately high cholesterol, according to the National Institutes of Health. The effective ingredient in Metamucil is blond psyllium, a herb that is a rich natural source of fiber.
Blond psyllium seems to be most effective at reducing cholesterol levels when taken with other foods during meal times, says the National Institutes of Health. There is also some evidence that the consumption of blond psyllium makes it possible to reduce the dose of certain cholesterol medications. However, a patient should not adjust medication dosages without a doctor's approval.