Heart: The Best-Established Area of Cacao Research

This is where the evidence is strongest. Two independent meta-analyses, pooling dozens of randomized trials between them, found that cacao flavanols improve blood-vessel function and modestly lower blood pressure.

What the studies found: A 2012 analysis pooling 42 randomized trials (1,297 participants) found cocoa flavanols improved flow-mediated dilation (a measure of how well blood vessels widen) and modestly reduced blood pressure.¹ A 2017 Cochrane review of 35 trials (1,804 participants) found flavanol-rich cocoa lowered blood pressure by roughly 1.8 mmHg on average, and more than that in people who already had high blood pressure.² An analysis of Panamanian death records from 2000–2004 found the island-dwelling Kuna, who traditionally drink flavanol-rich cacao daily, died of heart disease and stroke at a small fraction of the mainland rate. That comparison counted deaths, not cups. Nobody measured what anyone drank, so diet, lifestyle and differences in medical record-keeping between the two regions can't be ruled out.³

Where to stay cautious: the large COSMOS trial (21,442 older adults) tested a cocoa extract pill, not a beverage, and did not hit its main goal of reducing cardiovascular events overall. It did find a 27% reduction in cardiovascular deaths specifically, but that was a secondary finding, not the trial's primary result.⁴

Mind: Promising, But Still Emerging

Several smaller studies have found encouraging signals. The single largest trial to date did not confirm a benefit, so this remains early-stage work.

What the studies found: A small 2015 crossover trial (18 adults aged 50–65) found that a high-flavanol cocoa drink increased blood flow to two specific brain regions, measured two hours after drinking it.⁵ The "Cocoa, Cognition and Aging" study put 90 cognitively healthy elderly participants on 8 weeks of higher- or lower-flavanol cocoa, and found the higher-flavanol groups improved on cognitive tests, blood pressure and insulin resistance. Their scores on the standard global cognition screen were unchanged.⁶

Where the largest trial landed: COSMOS-Mind, over 2,200 participants across three years, is the biggest cognitive trial run on this question. Daily cocoa extract had no significant effect on overall cognition.⁷

Muscle & Energy: The Least Settled Area

This is the area with the least consistent evidence. A widely cited 2011 mouse study found that an isolated cacao flavanol (epicatechin) improved treadmill endurance and increased muscle mitochondrial density, in mice, not people.⁸ Two small human studies found encouraging changes in muscle-biopsy markers, with fine print attached: one enrolled five patients with both type 2 diabetes and advanced heart failure, the other seven men with Becker muscular dystrophy, and neither had a placebo group. The muscular dystrophy study measured strength and walking distance directly and found no improvement in either.⁹

Where the evidence pushes back: when researchers ran placebo-controlled trials in healthy people who were training, recreationally active adults on a four-week cycling program¹⁰ and trained endurance athletes across a ten-week season,¹¹ the supplement added nothing to performance beyond what the training alone produced. In both trials it appeared to blunt part of the adaptation: the placebo groups gained aerobic capacity and mitochondrial markers that the supplemented groups did not. A 2018 systematic review covering athletes, untrained adults and clinical populations reached the same verdict on performance. Cacao flavanols may improve blood-vessel function and reduce exercise-induced oxidative stress, but they do not make you faster or stronger.¹² We are not making an energy or performance claim here.

Gut & Digestion: No Trial Has Tested It

The popular version of this story is better than the evidence behind it.

What is established: coffee stimulates gastric acid secretion, which isn't controversial.¹³ Caffeine is one of the compounds responsible; a 2017 study identified bitter-taste receptors on stomach cells that caffeine acts on directly to trigger acid release.¹⁴ And a 2026 meta-analysis of 40 studies and more than 122,000 people found coffee drinkers reported reflux disease modestly more often than non-drinkers: 34.9% versus 30.7%.¹⁵

What that does and doesn't mean for Choffy: Choffy has substantially less caffeine than brewed coffee, though not zero (published figures and their sources are on our coffee alternative page). Less caffeine is a reasonable basis for expecting a smaller acid response. But that is an inference from a mechanism, not a measured result. Nobody has run a trial comparing brewed cacao to coffee for digestive symptoms in people. Plenty of our customers tell us Choffy sits easier than coffee did. That is their experience, not a clinical finding.

Two claims we've dropped: you'll see "cacao is less acidic than coffee" repeated a lot, including by people selling cacao. We went looking for a solid source and couldn't find one. Measured pH for brewed coffee lands around 4.9–5.1,¹⁶ and fermented cacao routinely sits in the same range or below it, so that comparison is off this page. The second is chlorogenic acids as the culprit in coffee: the most recent review of coffee and the digestive tract concludes they don't affect gastric acid secretion at all, and may protect the stomach lining.¹³

Where to stay cautious: cacao's effect on gut bacteria is mixed. Cocoa polyphenols appear to encourage beneficial bacteria including Bifidobacterium,¹⁷ while a rat study that isolated theobromine on its own found Bifidobacterium went the other way, alongside a decline in pathogenic bacteria.¹⁸ Rats aren't people, and isolated theobromine isn't a cup of Choffy.

Where the Evidence Stands

Cacao's cardiovascular research is the strongest and most consistent of the four areas. The cognitive research is real but preliminary, sitting alongside one large null result. The muscle/energy research doesn't currently support a performance claim in healthy adults. The digestion story is an inference rather than a result: coffee stimulates stomach acid, Choffy has far less caffeine, so a smaller effect is a reasonable expectation. No trial has tested it, and the acidity comparison people repeat doesn't survive checking. We'll update this page as new research comes out.

Important: most positive studies used concentrated flavanol doses (176–900+ mg) from specially processed extracts or standardized drinks, which may differ from what a cup of brewed Choffy delivers. This page describes published research on cacao compounds generally. It is not a clinical claim about Choffy as a product, and it is not medical advice. Talk to your doctor before making dietary changes, especially if you are pregnant, nursing, or managing a health condition.

Sources

1. Hooper L, Kay C, Abdelhamid A, et al. "Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomized trials." American Journal of Clinical Nutrition, 2012;95(3):740–51 (42 trials, 1,297 participants). Read study
2. Ried K, Fakler P, Stocks NP. "Effect of cocoa on blood pressure." Cochrane Database of Systematic Reviews, 2017;CD008893 (35 studies, 1,804 participants; mean systolic reduction 1.76 mmHg). Read review
3. Bayard V, Chamorro F, Motta J, Hollenberg NK. "Does flavanol intake influence mortality from nitric oxide-dependent processes? Ischemic heart disease, stroke, diabetes mellitus, and cancer in Panama." International Journal of Medical Sciences, 2007;4(1):53–58. Read study. Retrospective analysis of national death records, 2000–2004; cacao intake was not measured.
4. Sesso HD, Manson JE, Aragaki AK, et al. "Effect of cocoa flavanol supplementation for the prevention of cardiovascular disease events: the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial." American Journal of Clinical Nutrition, 2022;115(6):1490–1500 (21,442 participants). The primary cardiovascular endpoint was not met; the 27% reduction in cardiovascular death was a pre-specified secondary endpoint. Read study
5. Lamport DJ, Pal D, Moutsiana C, et al. "The effect of flavanol-rich cocoa on cerebral perfusion in healthy older adults during conscious resting state: a placebo controlled, crossover, acute trial." Psychopharmacology, 2015;232(17):3227–34 (18 participants aged 50–65). Read study
6. Mastroiacovo D, Kwik-Uribe C, Grassi D, et al. "Cocoa flavanol consumption improves cognitive function, blood pressure control, and metabolic profile in elderly subjects: the Cocoa, Cognition, and Aging (CoCoA) Study." American Journal of Clinical Nutrition, 2015;101(3):538–48 (90 participants, 8 weeks). Study supported by Mars, Incorporated. Read study
7. Baker LD, Manson JE, Rapp SR, et al. "Effects of cocoa extract and a multivitamin on cognitive function: a randomized clinical trial" (COSMOS-Mind). Alzheimer's & Dementia, 2023;19(4):1308–19; published online September 2022 (2,262 participants, 3 years). Cocoa extract had no effect on global cognition (mean z = 0.03; P = 0.28). Read study
8. Nogueira L, Ramirez-Sanchez I, Perkins GA, et al. "(-)-Epicatechin enhances fatigue resistance and oxidative capacity in mouse muscle." The Journal of Physiology, 2011;589(18):4615–31. Read study. Conducted in mice.
9. Taub PR, Ramirez-Sanchez I, Ciaraldi TP, et al. "Alterations in skeletal muscle indicators of mitochondrial structure and biogenesis in patients with type 2 diabetes and heart failure: effects of epicatechin rich cocoa." Clinical and Translational Science, 2012;5(1):43–47 (5 patients, open-label, no control group). Read study  |  McDonald CM, Ramirez-Sanchez I, Oskarsson B, et al. "(-)-Epicatechin induces mitochondrial biogenesis and markers of muscle regeneration in adults with Becker muscular dystrophy." Muscle & Nerve, 2021;63(2):239–49 (7 participants, open-label, no control group; no improvement in strength or 6-minute walk). Read study
10. Schwarz NA, Blahnik ZJ, Prahadeeswaran S, et al. "(-)-Epicatechin supplementation inhibits aerobic adaptations to cycling exercise in humans." Frontiers in Nutrition, 2018;5:132 (isolated epicatechin, 200 mg/day, 4 weeks, recreationally active adults aged 18–30). Read study
11. García-Merino JA, de Lucas B, Herrera-Rocha K, et al. "Flavanol-rich cocoa supplementation inhibits mitochondrial biogenesis triggered by exercise." Antioxidants, 2022;11(8):1522 (425 mg cocoa flavanols/day, 10 weeks, trained male endurance athletes). Read study
12. Decroix L, Soares DD, Meeusen R, Heyman E, Tonoli C. "Cocoa flavanol supplementation and exercise: a systematic review." Sports Medicine, 2018;48(4):867–92 (13 studies across athletes, untrained adults and clinical populations). Read review
13. Nehlig A. "Effects of coffee on the gastro-intestinal tract: a narrative review and literature update." Nutrients, 2022;14(2):399. Read review. States that chlorogenic acids do not modify gastric acid secretion, and reports the coffee–reflux literature as unresolved.
14. Liszt KI, Ley JP, Lieder B, et al. "Caffeine induces gastric acid secretion via bitter taste signaling in gastric parietal cells." Proceedings of the National Academy of Sciences, 2017;114(30):E6260–E6269. Read study. Caffeine delivered directly to the stomach accelerated acid secretion; caffeine tasted in the mouth delayed it.
15. Muftah M, McCarty TR, Hartnett D, et al. "Association of coffee intake with risk of gastroesophageal reflux disease and complications: a systematic review and meta-analysis." Clinical and Translational Gastroenterology, 2026;17(4):e00996 (40 studies, 122,074 participants; odds ratio 1.18, 95% CI 1.03–1.36). Read study
16. Rao NZ, Fuller M. "Acidity and antioxidant activity of cold brew coffee." Scientific Reports, 2018;8:16030 (measured pH 4.85–5.13 across six origins, hot and cold brewed). Read study
17. Sorrenti V, Ali S, Mancin L, et al. "Cocoa polyphenols and gut microbiota interplay: bioavailability, prebiotic effect, and impact on human health." Nutrients, 2020;12(7):1908. Read review
18. Martín-Peláez S, Camps-Bossacoma M, Massot-Cladera M, et al. "Effect of cocoa's theobromine on intestinal microbiota of rats." Molecular Nutrition & Food Research, 2017;61(10):1700238. Read study. Bifidobacterium decreased; Lactobacillus was unchanged; pathogenic Clostridium and E. coli also decreased.