Cocoa flavanols
Summary
Cocoa flavanols are polyphenols from cocoa beans. In COSMOS, 21,442 older adults given 500 mg of flavanols a day had no significant drop in total cardiovascular events, though cardiovascular deaths were 27% lower. Cognition did not improve over 3 years. Flavanol-rich cocoa lowered blood pressure about 2 mm Hg in short trials, more in people with hypertension.
Key facts
- Polyphenols (flavanols, including epicatechin) from the cocoa bean; trials used cocoa-extract capsules or flavanol-rich cocoa products[1][3]
- COSMOS, 21,442 adults, 500 mg/day for a median 3.6 years: total cardiovascular events HR 0.90 (not significant); cardiovascular death HR 0.73[1]
- COSMOS-Mind, 2,262 adults: no effect on global cognition over 3 years[2]
- Cochrane, 40 comparisons (1,804 people): about 1.8 mm Hg lower systolic and diastolic; about 4 mm Hg in hypertension[3]
- 3 graded human outcomes on this page
- October 11, 2026
How it works
ProposedCocoa flavanols are proposed to increase nitric oxide in blood-vessel walls, which relaxes arteries.[3]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Blood pressure | Grade B | Improved | Systematic review of 35 trials · n = 1,804 · 2017 | 1 row |
| Heart events | No effect | No effect | RCT · n = 21,442 · 2022 | 1 row |
| Cognition | No effect | No effect | RCT · n = 2,262 · 2023 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Blood pressure | Improved | Grade B | Systematic review · n = 1,804 · 2017 Mainly healthy adults in 35 trials (40 comparisons) Form: Flavanol-rich chocolate or cocoa products · Dose: 30–1,218 mg flavanols/day (mean 670 mg) · Duration: 2–18 weeks Systolic and diastolic pressure each fell about 1.8 mm Hg versus control; about 4 mm Hg systolic in people with hypertension and no significant change in normotensive people. Excluding trials with industry-employed authors shrank the effect slightly. | 28439881 (opens PubMed)Source [3] |
| Total cardiovascular events | No effect | No effect | RCT · n = 21,442 · 2022 US women aged 65+ and men aged 60+ without major cardiovascular disease Form: Cocoa extract capsules · Dose: 500 mg flavanols/day (including 80 mg epicatechin) · Duration: Median 3.6 years Total cardiovascular events did not fall significantly (HR 0.90, 95% CI 0.78–1.02); cardiovascular death, a secondary outcome, was 27% lower (HR 0.73). No safety concerns. | 35294962 (opens PubMed)Source [1] |
| Global cognition | No effect | No effect | RCT · n = 2,262 · 2023 Older adults (mean age 73) in COSMOS-Mind Form: Cocoa extract · Dose: 500 mg flavanols/day · Duration: 3 years Cocoa extract had no effect on a global cognition composite (mean z 0.03, P=0.28). | 36102337 (opens PubMed)Source [2] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Cocoa extract capsules or powder (standardized flavanols) | Varies | No head-to-head human absorption data in the sources cited here. | No safety concerns at 500 mg flavanols/day for a median 3.6 years.[1] | COSMOS heart and cognition trials |
| Dark chocolate or cocoa powder | Varies | No head-to-head human absorption data in the sources cited here. | Gastrointestinal complaints and nausea in 1% of active-group participants.[3] | Short blood-pressure trials |
Studied doses
Doses studied in human trials ranged from 30 mg to 1,218 mg of cocoa flavanols per day in blood-pressure trials of 2–18 weeks, and 500 mg per day for a median 3.6 years in COSMOS.[3][1]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Anyone counting on heart protection
- The largest trial missed its main outcome; the lower cardiovascular death rate was a secondary finding.[1]
- Chocolate as a supplement substitute
- Blood-pressure trials used flavanol-rich products; their effect was small and mostly in people with hypertension.[3]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Frequently asked questions
Do cocoa flavanols lower heart-attack risk?
In COSMOS, 500 mg a day did not significantly reduce total cardiovascular events, though cardiovascular deaths were lower as a secondary outcome.[1]
Do cocoa flavanols improve memory?
COSMOS-Mind found no effect on global cognition over 3 years.[2]
Does dark chocolate lower blood pressure?
Flavanol-rich cocoa lowered it about 2 mm Hg in short trials, more in people with hypertension.[3]
How much was studied?
COSMOS used 500 mg of cocoa flavanols a day, including 80 mg epicatechin.[1]
Sources
- [1]Effect of cocoa flavanol supplementation for the prevention of cardiovascular disease events: the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial. Am J Clin Nutr, 2022. RCT
- [2]Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial. Alzheimers Dement, 2023. RCT
- [3]Effect of cocoa on blood pressure. Cochrane Database Syst Rev, 2017. systematic-review
What changed
- New monograph. Every PMID checked against NCBI E-utilities (title, journal and year from the PubMed record); each evidence row written from its abstract; intake and safety facts from the cited fact sheets.