Lead investigator Dr. Ronald Watson, PhD, conducted the double-blind study of Stage 1 hypertensive men and women, average age 50, none of whom used medication. Participants took 200 mg of Pycnogenol per day for eight weeks. At the end of the study period, average systolic blood pressure had reduced to 134 mmHg, compared to a starting range of 140-159 mmHg, and diastolic blood pressure had reduced to an average of 94 mmHg, compared to a starting range of 90-99 mmHg.
Researchers believe that Pycnogenol elevates the production and blood levels of nitric oxide, whose action causes the muscles that surround blood vessels to relax and expand, increasing blood flow and reducing blood pressure. Stress hormones, which constrict muscles, reduce the diameter of blood vessels, and increase blood pressure.