Transcendental Meditation has been shown to produce Insufficient Evidence for Lowering Blood Pressure according to a recent review by the American Heart Association.
The paper, according to new research published in the American Heart Association journal Circulation: Cardiovascular Quality and Outcomes, clearly states that they have not endorsed TM or any other meditation method for lowering blood pressure. There's simply insufficient evidence to recommend Transcendental Meditation, but it probably won't do any harm (although there's a large base of previous evidence showing considerable harm associated with the practice of Transcendental Meditation).
It's really not all that surprising that they could not recommend Transcendental Meditation, as a previous review of many meditation techniques showed that Transcendental Meditation was the least beneficial and the worst meditation technique for lowering blood pressure.
As if this wasn't enough terrible news for the sellers of Transcendental Meditation, numerous improprieties were found in the research methodology that calls it's statistical manipulations into question.
As is typical in Transcendental Meditation research, the fact that there was a major conflict of interest with one of it's researchers is never mentioned. The person in question, Robert Schneider, MD (a cardiologist), actually appears in the documentary exposé David Wants to Fly, shilling for Transcendental Meditation from Maharishi's mansion in Holland. It turns out Dr. Schneider was a long time follower of the Maharishi's teachings and active in sales promotion for the organization. Tsk, tsk...