What the COSMOS Cocoa Flavanol Study Actually Found

The COSMOS study (COcoa Supplement and Multivitamin Outcomes Study, Sesso et al., American Journal of Clinical Nutrition, 2022) was a large randomized trial of 21,442 older adults that tested a 500 mg daily cocoa flavanol supplement — containing about 80 mg of (-)-epicatechin — against placebo. Its primary cardiovascular endpoint did not reach statistical significance, though the researchers reported signals in secondary analyses that they said warranted further study.

What COSMOS was

COSMOS stands for the COcoa Supplement and Multivitamin Outcomes Study, led by researchers at Brigham and Women's Hospital and Harvard and published by Sesso and colleagues in the American Journal of Clinical Nutrition in 2022. It was large and properly randomized: 21,442 older adults — men 60 and older, women 65 and older — assigned to a daily cocoa flavanol supplement or placebo, with a parallel arm testing a multivitamin, and followed for roughly three and a half years. The flavanol dose was 500 mg per day, standardized to include about 80 mg of (-)-epicatechin. That single figure is why 500 mg is treated as the field's reference point.

What it found — and what it didn't

Here honesty matters. The trial's primary cardiovascular endpoint did not reach statistical significance, meaning COSMOS did not prove that cocoa flavanols prevent cardiovascular disease. The authors did report signals in pre-specified secondary analyses that they described as promising enough to justify further study, while cautioning against over-reading them. In plain terms, COSMOS is best understood as a serious, encouraging-but-inconclusive trial that established a credible daily amount and a strong safety profile — not as a finish line. Anyone selling you certainty from it is overstating the science.

How CCV-3 relates — and how it doesn't

A few things are worth stating cleanly. HarmonyMD is not the COSMOS product; CCV-3® was not the supplement used in the trial. What CCV-3 shares is the same active family, standardized and then some: 1,200 mg of cocoa flavanols per scoop — more than double the trial's amount, about 2.4 times — plus 600 mg of (-)-epicatechin. We cite COSMOS as context for why cocoa flavanols are worth taking seriously, not as evidence about our specific drink mix. Individual results vary, and no single trial changes that.

Did COSMOS prove cocoa prevents heart disease?

No. Its primary endpoint was not statistically significant. It's an important, encouraging trial, but it did not establish prevention.

Was CCV-3 the supplement tested in COSMOS?

No. COSMOS used a separate cocoa flavanol supplement. HarmonyMD is not the COSMOS product.

What dose did COSMOS use?

500 mg of cocoa flavanols per day, including about 80 mg of (-)-epicatechin.