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Cof5.0
Cocoa Flavanols Research
Mostly mechanism / observational
6 peer-reviewed studies
Our research database did not respond in time, so this list covers only our curated studies. It refreshes automatically.
What the evidence says
Mostly mechanism / observational
Most Cocoa Flavanols studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 2014–2025 with a typical study size of 21,442 participants.
Based on 6 studies · 2 meta-analyses · 4 RCTs · 42,884 total participants
Confidence
High confidence
What the studies found
0helped1unclear· 5 more without graded effect data
By outcome
Heart & blood pressureSmall blood-pressure reduction (~2 mmHg) and improved endothelial function; COSMOS missed its primary CV endpoint but cut CV death 27% as a secondary outcome · 2-8 weeks for BP/vascular markers; years for hard outcomes
Too few graded studies2 studies
Active research area
3 studies in the last 5 years · Latest meta-analysis: 2019
201420192025
1RCTCited 148×n=21,442 · very large study2022
In plain English: Cocoa extract supplementation did not significantly reduce total cardiovascular events among older adults but reduced CVD death by 27%.
Sesso HD, Manson JE, Aragaki AK, Rist PM, Johnson LG, et al.; COSMOS Research Group · Am J Clin Nutr (2022)
21,442 older US adults, 500mg flavanols/day, median 3.6 years, double-blind placebo-controlled
PRIMARY endpoint (total CV events) NOT significant: HR 0.90 (95% CI 0.78-1.02, P=0.11)
Secondary CVD death reduced 27%: HR 0.73 (95% CI 0.54-0.98)
In plain English: This review provides moderate-quality evidence that flavanol-rich cocoa products cause a small (2 mmHg) blood pressure-lowering effect in mainly healthy adults in the short term.
4Age-related macular degenerationRCTCited 3×n=21,442 · very large study2025
In plain English: For the primary composite end point, there were 159 cases (1.5%) in the cocoa extract group and 185 cases (1.7%) in the placebo group (hazard ratio [HR], 0.87; 95% CI, 0.71-1.08; P = .21).
Christen WG et al. · JAMA Ophthalmology (2025)
No clear effect
← WorseNo effectBetter →
Could be chance
In this large randomised ancillary study (COSMOS), cocoa flavanol supplementation did NOT significantly reduce the primary composite age-related macular degeneration outcome (HR 0.87; 95% CI 0.71-1.08; P = .21).
A non-prespecified analysis suggested a 23% lower risk during the first 2 years of treatment (HR 0.77; 95% CI 0.59-1.01), but this was not a confirmed effect.
Bottom line: a null primary result over ~3.6 years of follow-up — no evidence to recommend cocoa flavanols for AMD prevention.
In plain English: This meta-analysis provides evidence that cocoa flavanols could significantly improve endothelial function, with an optimal effect observed with 710 mg total flavanols.
Sun Y, Zimmermann D, De Castro CA, Actis-Goretta L · Food Funct (2019)
15 articles, 18 intervention arms pooled
Flow-mediated dilation improved by 1.17% (95% CI 0.76-1.57%)