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COcoa Supplement and

Multivitamin Outcomes Study

Welcome to the COSMOS Trial!

The COcoa Supplement and Multivitamin Outcomes Study (COSMOS)  at Brigham and Women's Hospital – an affiliate of Harvard Medical School (Boston, MA) – and the Fred Hutchinson Cancer Research Center (Seattle, WA) is a clinical trial that randomized 21,444 men and women across the U.S. The study has investigated whether taking daily supplements of cocoa flavanols (600 mg/day) or a common multivitamin reduces the risk for developing heart disease, stroke, cancer, and other important health outcomes.

Although results from previous studies have been promising, the health benefits of taking these supplements have not yet been proven. The only way to determine whether or not cocoa flavanol and multivitamin supplements help maintain health is by conducting a large-scale trial, such as COSMOS.

We are excited to announce that study pill taking has ended on December 31, 2020. Other important information about the end of this phase of the COSMOS trial can be found in COSMOS Connection Issue 5, which you can access in the COSMOS Connection Newsletters tab.

To learn more about this important research endeavor, please click on the links in the left column.


Brigham and Women's Hospital  | Division of Preventive Medicine | 900 Commonwealth Avenue, Fl 3  |  Boston, MA  02215  |  800-633-6913