NR-009
Ingredient Atlas entry · Food
Cacao
The seeds of the cacao tree, Theobroma cacao
The roasted seeds of the cacao tree, eaten as cocoa and dark chocolate or taken as a flavanol extract, and studied mostly for the heart and blood vessels, blood pressure and blood sugar. Here is every study in people we could find, sorted from each study's summary.
- Taken as: cocoa, dark chocolate or extract
- Dosed as grams of chocolate or mg of flavanols
- A single dose or a few weeks
The research map
From every paper to the studies that matter
Most research on cacao is in the lab, about growing and processing the crop, or surveys of what people eat. Only a small share gives it to people in a study, and that is what this page is about.
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11,727 papers mention cacao.Every record in PubMed, all years
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917 are about people.The rest: 2,507 lab and animal studies, 1,091 reviews, 7,212 on chemistry, farming and more
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439 give cacao on its own.136 more test it in milk chocolate, a drink or a blend
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201 are randomised against a placebo.Randomised controlled trials In a randomised controlled trial, people are put into groups by chance, one taking the treatment and one a placebo or other comparison. Chance spreads differences such as age and health evenly, so a difference between the groups is more likely to be down to the treatment., the strongest kind of study
Bar lengths use a square-root scale so the small numbers stay visible.
At a glance
How much research there is
- 439 studies giving cacao to people
- 201 of them randomised against a placebo A placebo-controlled trial compares a real treatment with a dummy that looks the same, the placebo. People often feel better when they expect to, so comparing against a placebo shows how much of the change comes from the treatment itself.
- 36,721 people taking part, where studies say
- 178 systematic reviews A systematic review searches for every study on a question in a set, written-down way, judges the quality of each and sums up what they show together. Many include a meta-analysis. The Atlas lists these as pooled reviews. pooling the trials
Studies in people, by year published
Cocoa, cocoa extract or dark chocolate on its own.
Randomised, placebo-controlled
Other designs
What was measured
What the studies looked at
Each study can measure several things. Choose a topic to see its studies in the list below.
Studies in people with a diagnosed condition are counted here and listed with their population. We describe what they measured, not what they might treat. Most studies also report safety; see below.
Doses and extracts
What was tested, and how much
Studies give cacao in very different forms, so milligrams don't compare from one study to the next. Some count the grams of chocolate or cocoa powder (shown here as milligrams, so 40 g of chocolate is 40,000 mg), others count only the flavanols inside, often a few hundred milligrams. Many studies gave one dose shortly before testing.
Daily amount, one dot per study
Summary read234 studies don't give a daily amount in their summary and aren't shown.
Studies per extract
Named extracts are the maker's brand. "Not named" means the study didn't say.
Every study
All studies in people
Filter the list, then open a study on PubMed. Each row comes from the study's published summary, and doses are as each study reported them, grams of product or milligrams of flavanols.
| Study | Who took part | People | Extract and daily dose | Length |
|---|---|---|---|---|
| Chou 2026RCT, placebo | Older adults, ambulatory | 603 | COSMOS cocoa extract | 104 weeks |
| Rist 2026RCT, placebo | Older US adults, factorial trial | 506 | COSMOS cocoa extract, 500 mg | 104 weeks |
| Gómez Nieto 2026RCT, active or other control | Healthy older adults | 59 | Not named, 2,500 mg | 12 weeks |
| Riley 2026RCT, active or other control | Adults with overweight or obesity | 48 | Not named, 61,000 mg | 4 weeks |
| Karataş 2026Crossover, placebo | Healthy young adult students | 48 | Not named, 710 mg | – |
| Munguía 2026RCT, placebo | Long COVID patients with fatigue | 46 | Epicatechin-enriched cacao supplement | 13 weeks |
| Daniele 2026Crossover, placebo | Healthy young males | 40 | Not named, 150 mg | – |
| Chatagnier 2026RCT, active or other control | Healthy adults | 36 | Dark chocolate 70% cocoa, 50,000 mg | 2 weeks |
| Lin 2026Single-arm or open-label | Myopic patients | 31 | Dark chocolate, 30,000 mg | 0 weeks |
| Daniele 2026Crossover, placebo | Healthy older adults | 20 | Not named, 695 mg | – |
| Morikawa 2026Crossover, placebo | Healthy young males | 19 | Not named | – |
| Hamaoka 2026Crossover, placebo | Healthy older adults | 17 | Not named, 26,000 mg | – |
| Hata 2026Crossover, placebo | Healthy young men | 11 | Flavanol-rich dark chocolate, 50,000 mg | – |
| Kinta 2026Crossover, placebo | Healthy adults | – | Not named | – |
| Li 2025RCT, placebo | Older US adults, factorial trial | 598 | COSMOS cocoa extract, 500 mg | 104 weeks |
| Weigant 2025RCT, placebo | Healthy young adults | 75 | Not named | 4 weeks |
| Duse 2025RCT, placebo | Healthy older adults | 63 | Not named, 1,000 mg | 4 weeks |
| Daniele 2025Crossover, placebo | Healthy young and older adults | 60 | Not named, 695 mg | – |
| Kemp 2025Non-randomised controlled | Hemodialysis patients with CKD | 59 | Not named, 40,000 mg | 9 weeks |
| Köhlmoos 2025Other | Healthy young women | 44 | Dark chocolate (theobromine), 40,000 mg | 0 weeks |
| Kababie-Ameo 2025RCT, placebo | Adults with type 2 diabetes and neuropathy | 39 | Not named, 50 mg | 12 weeks |
| Gavilán 2025RCT, placebo | Older US adults, pilot substudy | 37 | COSMOS cocoa extract, 500 mg | 52 weeks |
| Altinok 2025Crossover, placebo | Healthy adults | 36 | Not named, 623 mg | – |
| Wang 2025RCT, active or other control | Healthy young women | 31 | Not named | 0 weeks |
| Johnson 2025RCT, placebo | Postmenopausal women | 26 | Not named, 20,000 mg | 4 weeks |
| Balasekaran 2025Crossover, placebo | Healthy adults | 20 | Not named | – |
| Pannunzio 2025RCT, active or other control | Adults with MASH | 19 | Not named, 40,000 mg | 2 weeks |
| Tsukamoto 2025Crossover, placebo | Healthy young males | 18 | Not named, 500 mg | – |
| Gargiulo 2025Crossover, placebo | Healthy volunteers | 17 | Not named | – |
| Safari 2025Crossover, placebo | Trained female CrossFit athletes | 15 | Not named, 30,000 mg | 0 weeks |
| Hata 2025Crossover, placebo | Healthy young men | 12 | Not named, 1,285 mg | – |
| De Mul 2025Single-arm or open-label | Healthy volunteers | 7 | Dark chocolate, 100,000 mg | 0 weeks |
| Ottaviani 2025RCT, placebo | Older US adults, COSMOS preprint | – | COSMOS cocoa extract, 500 mg | – |
| Ottaviani 2025RCT, placebo | Older US adults, COSMOS subcohort | – | COSMOS cocoa extract, 500 mg | – |
| Ito 2025Non-randomised controlled | Japanese women with constipation | – | Dark chocolate | – |
| Vyas 2024RCT, placebo | Older US adults | 573 | Not named, 500 mg | 104 weeks |
| Daszkiewicz 2024Other | Adults with acne | 92 | Not named, 50,000 mg | 4 weeks |
| Fazdria 2024Non-randomised controlled | Primigravida women in first-stage labour | 90 | Not named | – |
| Abdoli 2024RCT, active or other control | Menopausal women | 60 | Not named, 12,000 mg | 8 weeks |
| Akyürek 2024Crossover, placebo | Healthy young adults | 48 | Not named, 415 mg | – |
| Vordos 2024Single-arm or open-label | Male amateur endurance runners | 46 | Not named, 50,000 mg | 2 weeks |
| Baynham 2024Crossover, placebo | Healthy young adults | 23 | Not named, 150 mg | – |
| Sacconi 2024RCT, active or other control | Healthy young adults | 20 | Not named, 20,000 mg | – |
| Latif 2024Single-arm or open-label | Healthy young men, two ethnic groups | 20 | Dark chocolate, 396 mg | 0 weeks |
| Sasaki 2024RCT, active or other control | Healthy middle-aged adults | 18 | Not named, 25,000 mg | – |
| Alba 2024Crossover, placebo | Healthy young adults | 11 | Cocoa flavanols, 900 mg | 1 weeks |
| Suther 2024Crossover, placebo | Healthy adults | 8 | Cocoa-derived flavanols, 900 mg | 1 weeks |
| Draelos 2024Pharmacokinetic | Healthy women | 5 | Not namedOn the skin | – |
| Ismaeel 2024RCT, placebo | People with peripheral artery disease | – | Cocoa flavanol-rich beverage | – |
| Hamel 2024Crossover, placebo | Young healthy adults | – | Not named, 695 mg | – |
| Vazan 2024RCT, active or other control | Healthy adults | – | Not named | – |
| Mancin 2024RCT, active or other control | Elite male soccer players | – | Not named, 30,000 mg | 4 weeks |
| Villegas-Aguilar 2024Pharmacokinetic | Healthy volunteers | – | Not named | – |
| Gröne 2023RCT, placebo | Healthy elderly people | 68 | Not named, 1,000 mg | 4 weeks |
| García-Cordero 2023RCT, active or other control | Healthy adults aged 45 to 85 | 60 | Not named, 2,500 mg | 12 weeks |
| Murakami 2023RCT, placebo | Middle-aged women with fatigue | 60 | Flavanol-rich cacao extract, 240 mg | 8 weeks |
| Ribeiro 2023Non-randomised controlled | Haemodialysis patients with chronic kidney disease | 59 | Dark chocolate 70% cocoa (40 g, 3x/week) | 8 weeks |
| Nuha 2023RCT, active or other control | Women with primary dysmenorrhea | 45 | Not named, 35,000 mg | – |
| Gröne 2023RCT, placebo | Men undergoing transradial angiography | 36 | Cocoa flavanol supplement, 1,000 mg | – |
| Simpson 2023RCT, placebo | Overweight or obese premenopausal women with insulin resistance | 32 | High-flavanol cocoa drink, 1,218 mg | 4 weeks |
| González-Garrido 2023Single-arm or open-label | Young adults, normal weight and class II obesity | 30 | Not named | 1 weeks |
| Hajati 2023Crossover, placebo | Healthy young men and women | 30 | Not named | – |
| Sasaki 2023RCT, active or other control | Healthy middle-aged adults | 26 | Not named, 25,000 mg | – |
| Nocella 2023RCT, active or other control | Elite football players | 24 | Not named | 4 weeks |
| Ottaviani 2023Pharmacokinetic | Healthy volunteers and ileostomists | 20 | Cocoa flavan-3-ols with methylxanthines | – |
| Grassi 2023Crossover, placebo | Healthy nonsmokers | 20 | Cocoa powder (10 g/day, 0-800 mg flavonoids) | 1 weeks |
| Parmenter 2023Pharmacokinetic | Healthy adults | 16 | Not named | – |
| Santos 2023Crossover, placebo | Healthy adults | 13 | Microencapsulated cocoa | – |
| Bloomfield 2023Crossover, placebo | Healthy adults under hypoxia | 12 | Cocoa flavanols | – |
| Banaei 2023Crossover, placebo | Male cyclists | 10 | Not named | – |
| Nájera 2023RCT, placebo | Postmenopausal women | – | Epicatechin-enriched cacao supplement | 12 weeks |
| Sesso 2022RCT, placebo | Older adults free of major cardiovascular disease | 21,442 | Cocoa extract (COSMOS), 500 mg | 187 weeks |
| Altınok 2022Crossover, placebo | Healthy young adults | 80 | Cocoa flavanols (415 mg) | – |
| Shin 2022RCT, active or other control | Healthy adults aged 20 to 30 | 48 | Dark chocolate 85% and 70% cocoa, 30,000 mg | 3 weeks |
| Vettori 2022RCT, active or other control | Older patients with cancer in palliative care | 46 | Dark chocolate 55% cocoa | 4 weeks |
| García-Merino 2022RCT, placebo | Male endurance athletes | 42 | Flavanol-rich cocoa, 5,000 mg | 10 weeks |
| Tanghe 2022Crossover, placebo | Adults with and without type 2 diabetes | 35 | Cocoa flavanol capsules, 790 mg | – |
| Coe 2022RCT, placebo | People with Parkinson disease and fatigue | 30 | Flavonoid-rich cocoa beverage, 18,000 mg | 1 weeks |
| Bapir 2022Crossover, placebo | Healthy adults and adults with type 2 diabetes | 22 | Cocoa flavanol capsules, 1,350 mg | – |
| Milenkovic 2022RCT, placebo | Healthy middle-aged men | 20 | Cocoa flavanols, 900 mg | 4 weeks |
| Dural 2022RCT, active or other control | Adults with heart failure and reduced ejection fraction | 20 | Dark and milk chocolate | – |
| Seecheran 2022Single-arm or open-label | Adults with stable coronary artery disease on antiplatelet therapy | 20 | Dark chocolate 65% cocoa (30 g/day), 30,000 mg | 1 weeks |
| Papakonstantinou 2022RCT, active or other control | Healthy young adults | 12 | Sugar-free cocoa powder with fat-free milk | – |
| Bapir 2022Crossover, placebo | Healthy young adults | 11 | Cocoa flavanol capsules, 862 mg | 1 weeks |
| Tabone 2022Single-arm or open-label | Male endurance athletes | – | Cocoa rich in procyanidins | – |
| Nemoto 2022RCT, active or other control | Healthy middle-aged adults | – | Dark chocolate | 4 weeks |
| Sloan 2021RCT, placebo | Healthy adults aged 50-75 | 211 | Not named, 770 mg | 12 weeks |
| Garcia-Yu 2021RCT, active or other control | Postmenopausal women | 132 | Not named, 10,000 mg | 26 weeks |
| Balayssac-Siransy 2021RCT, active or other control | Healthy young black African men | 130 | Cocoa powder 100%, 10,000 mg | 3 weeks |
| García-Cordero 2021RCT, active or other control | Healthy adults aged 50 to 75 | 60 | Cocoa powder | 12 weeks |
| Hooshmand Moghadam 2021RCT, active or other control | Adolescent boys with obesity | 50 | Dark chocolate 83% cocoa, 30,000 mg | 6 weeks |
| Siransy-Balayssac 2021RCT, active or other control | Young black African men | 49 | Not named, 10,000 mg | 3 weeks |
| Kawakami 2021Crossover, placebo | Healthy adults | 48 | Not named | – |
| Fakhari 2021RCT, active or other control | Diabetic women with neuropathy | 36 | Not named | 8 weeks |
| Baynham 2021Crossover, placebo | Healthy young men | 30 | Not named, 150 mg | – |
| Barrera-Reyes 2021Pharmacokinetic | Healthy young adults | 20 | Polyphenol-rich cocoa powder, 1,300 mg | 4 weeks |
| Hernández-González 2021RCT, active or other control | Postmenopausal women | 19 | Not named, 100,000 mg | 2 weeks |
| Presler 2021RCT, placebo | Exercise trained females | 18 | Not named, 20,000 mg | 4 weeks |
| Sadler 2021Crossover, placebo | Sedentary middle-aged adults | 17 | Not named, 400 mg | 1 weeks |
| Sian 2021Crossover, placebo | Healthy older adults | 12 | Not named, 475 mg | – |
| Hakeem Said 2021Pharmacokinetic | Healthy volunteers, cocoa feeding trial | – | Not named | – |
| Garcia-Yu 2020RCT, active or other control | Postmenopausal women | 140 | Not named, 10,000 mg | 26 weeks |
| Suominen 2020RCT, active or other control | Healthy older adults aged 65-75 | 100 | Not named, 50,000 mg | 8 weeks |
| Lamport 2020RCT, placebo | Healthy young adults aged 18-24 | 98 | Not named, 35,000 mg | – |
| Christen 2020Single-arm or open-label | Healthy volunteers | 62 | Dark chocolate, 50,000 mg | 2 weeks |
| Eskandari 2020RCT, active or other control | Obese adolescent boys | 48 | Not named, 30,000 mg | 6 weeks |
| McDermott 2020RCT, placebo | Older adults with peripheral artery disease | 44 | Not named, 15,000 mg | 26 weeks |
| Gröne 2020Other | Healthy young and elderly adults | 39 | Not named, 900 mg | 2 weeks |
| Corr 2020RCT, placebo | Healthy adults | 23 | Not named, 1,245 mg | – |
| Scuderi 2020Crossover, placebo | Healthy young adults | 18 | Not named, 100,000 mg | – |
| Caponio 2020Other | Healthy volunteers given dark chocolate | 16 | Not named | – |
| Hakeem Said 2020Pharmacokinetic | Healthy volunteers given polyphenol-rich cocoa | 15 | Not named | 0 weeks |
| Patel 2020Crossover, placebo | Healthy adults | 15 | Not named, 1,060 mg | – |
| Kim 2020Crossover, placebo | Healthy young African and Caucasian Americans | 14 | Not named | – |
| Ellinger 2020Pharmacokinetic | Healthy nonsmokers | 12 | Not named | – |
| Shaw 2020Crossover, placebo | Trained cyclists | 12 | Not named, 120,000 mg | 2 weeks |
| Regecova 2020RCT, active or other control | Healthy young women | – | Not named | – |
| Ángel García-Merino 2020RCT, placebo | Endurance athletes | – | Not named, 5,000 mg | 10 weeks |
| León-Flores 2020RCT, placebo | Overweight adults | – | Not named | – |
| Davis 2020RCT, placebo | Adults with type 2 diabetes | – | Not named | – |
| Sarriá 2020Other | Healthy and cardiovascular risk adults | – | Not named | – |
| Gratton 2020Crossover, placebo | Healthy young adults | – | Not named | – |
| Munguia 2019RCT, placebo | Middle-aged and older adults | 60 | Not named | 12 weeks |
| Coe 2019RCT, placebo | People with relapsing remitting multiple sclerosis and fatigue | 40 | Not named | 6 weeks |
| Nishiwaki 2019RCT, active or other control | Healthy college students | 32 | Not named, 20,000 mg | 4 weeks |
| Pereira 2019RCT, active or other control | Healthy young adults | 30 | Not named, 20,000 mg | 4 weeks |
| Wiese 2019RCT, active or other control | Moderately obese adults | 30 | Not named, 10,000 mg | 4 weeks |
| Tsang 2019RCT, placebo | Adults from health and social care setting | 26 | Not named, 25,000 mg | 4 weeks |
| Decroix 2019Crossover, placebo | Adults with type 1 diabetes and healthy controls | 22 | Not named, 900 mg | – |
| Siedlecki 2019RCT, active or other control | Healthy adults | 22 | Not named, 20,000 mg | – |
| Barrera-Reyes 2019Crossover, placebo | Healthy young adults | 20 | Not named | – |
| Sumiyoshi 2019RCT, placebo | Healthy young adults | 18 | Not named | 4 weeks |
| Fox 2019Crossover, placebo | Healthy volunteers | 16 | Not named, 100,000 mg | 1 weeks |
| de Carvalho 2019RCT, active or other control | Elite male rugby players | 13 | Not named | 1 weeks |
| Gómez-Juaristi 2019Pharmacokinetic | Healthy men and women | 13 | Not named | – |
| Rynarzewski 2019Crossover, placebo | Adults with type 2 diabetes and hypertension | 12 | Not named, 2,500 mg | – |
| Calzavara-Pinton 2019Single-arm or open-label | Healthy adults | 10 | Not named, 4,000 mg | 1 weeks |
| Shiina 2019Crossover, placebo | Prediabetic adults | – | Not named | – |
| Casperson 2019Other | Adult chocolate consumers | – | Not named | – |
| Crossland 2019Other | Healthy older males, muscle gene expression | – | Cocoa flavanol supplement, 1,050 mg | 1 weeks |
| Barrios 2018RCT, placebo | Healthy young men | 100 | Not named, 80,000 mg | 1 weeks |
| Leyva-Soto 2018RCT, active or other control | Healthy young volunteers | 84 | Not named, 2,000 mg | 26 weeks |
| Adamo 2018RCT, active or other control | Healthy volunteers | 61 | Not named | 2 weeks |
| Karabay 2018Crossover, placebo | University students | 48 | Not named | – |
| Davinelli 2018RCT, active or other control | Healthy adults | 48 | Not named, 4,000 mg | 4 weeks |
| Rodriguez-Mateos 2018RCT, placebo | Healthy young men | 45 | Not named, 690 mg | 4 weeks |
| Jafarirad 2018RCT, active or other control | Adults with type 2 diabetes | 44 | Not named, 30,000 mg | 8 weeks |
| Dicks 2018RCT, placebo | Adults with type 2 diabetes and hypertension | 42 | Not named, 2,500 mg | 12 weeks |
| Chalyk 2018Single-arm or open-label | Healthy young and middle-aged men | 33 | Not named, 10,000 mg | 4 weeks |
| Rabin 2018Crossover, placebo | Adults without eye disease | 30 | Not named | – |
| von Wowern 2018Single-arm or open-label | Pregnant women with compromised uteroplacental blood flow | 25 | Not named | 0 weeks |
| Santiago-Rodríguez 2018Non-randomised controlled | Healthy young adults, EEG study | 25 | Not named | 1 weeks |
| Cavarretta 2018RCT, active or other control | Elite football players | 24 | Not named | 4 weeks |
| Decroix 2018Crossover, placebo | Healthy young adults | 20 | Not named, 530 mg | – |
| Costa-Bauza 2018Single-arm or open-label | Healthy volunteers | 20 | Not named, 40,000 mg | – |
| Montagnana 2018Single-arm or open-label | Healthy men | 18 | Not named, 50,000 mg | – |
| Sadek 2018Single-arm or open-label | Children with autism spectrum disorder | 17 | Not named, 16,000 mg | 4 weeks |
| Sadek 2018Single-arm or open-label | Children with autism spectrum disorder | 16 | Not named, 16,000 mg | 4 weeks |
| Decroix 2018Crossover, placebo | Well-trained male cyclists | 14 | Not named | 1 weeks |
| Tsukamoto 2018Crossover, placebo | Healthy young men | 10 | Not named, 563 mg | – |
| Angiletta 2018RCT, active or other control | Obese adults at risk of insulin resistance | – | Not named | – |
| Meier 2017RCT, active or other control | Adult participants | 258 | Not named | – |
| Bujold 2017RCT, active or other control | Pregnant women at risk of preeclampsia | 131 | Not named | 12 weeks |
| Teixeira 2017Crossover, placebo | Adults with HIV on antiretroviral therapy | 110 | Not named | 2 weeks |
| Souza 2017Crossover, placebo | Adults with HIV on antiretroviral therapy | 92 | Not named, 65,000 mg | 2 weeks |
| Lee 2017RCT, active or other control | Overweight and obese adults | 48 | Not named, 61,000 mg | 4 weeks |
| Sansone 2017Crossover, placebo | Healthy volunteers | 47 | Not named | – |
| Ostertag 2017Crossover, placebo | Healthy volunteers | 42 | Not named | – |
| Loffredo 2017RCT, active or other control | Patients with non-alcoholic steatohepatitis | 19 | Not named, 40,000 mg | 2 weeks |
| González-Garrido 2017Single-arm or open-label | Healthy volunteers | 15 | Not named | – |
| Montagnana 2017Single-arm or open-label | Healthy men | 15 | Not named, 50,000 mg | – |
| Marsh 2017Crossover, placebo | Healthy postmenopausal women | 14 | Not named | – |
| Marsh 2017Crossover, placebo | Healthy postmenopausal women | 12 | Not named | – |
| Decroix 2017Crossover, placebo | Well-trained male cyclists | 12 | Not named, 900 mg | – |
| Coe 2017Crossover, placebo | People with multiple sclerosis fatigue | 12 | Not named | – |
| Germonpré 2017RCT, active or other control | Male scuba divers | 9 | Not named, 30,000 mg | – |
| Montagnana 2017Other | Adults | – | Not named | – |
| Radosinska 2017Crossover, placebo | Healthy adults | – | Not named | – |
| Petrilli 2016Crossover, placebo | HIV-positive adults on antiretrovirals | 92 | Not named | 2 weeks |
| Kuebler 2016RCT, placebo | Healthy men aged 20-50 | 65 | Not named | – |
| Latif 2016RCT, placebo | Healthy medical students | 60 | Not named, 40,000 mg | 2 weeks |
| Rassaf 2016RCT, placebo | Hemodialysis patients with ESRD | 57 | Not named, 900 mg | 4 weeks |
| Grassi 2016Crossover, placebo | Healthy sleep-deprived adults | 32 | Not named | – |
| De Palma 2016Crossover, placebo | Adults with chronic heart failure | 32 | Not named, 50,000 mg | 4 weeks |
| Nirmala 2016RCT, active or other control | Schoolchildren aged 10-15 | 30 | Not named | – |
| Greenberg 2016Crossover, placebo | Healthy young men | 28 | Not named | – |
| Okamoto 2016RCT, active or other control | Postmenopausal women | 26 | Not named, 17,000 mg | 12 weeks |
| Vongraviopap 2016Single-arm or open-label | Acne-prone men | 25 | Not named | 4 weeks |
| Ibero-Baraibar 2016RCT, placebo | Overweight or obese middle-aged adults | 24 | Not named, 1,400 mg | 4 weeks |
| Phillips 2016Non-randomised controlled | Healthy volunteers | 20 | Cocoa flavanols, 350 mg | – |
| Dower 2016Crossover, placebo | Healthy men aged 40-80 | 20 | Not named | – |
| Taub 2016RCT, placebo | Sedentary middle-aged adults | 20 | Not named | 13 weeks |
| Loffredo 2016Crossover, placebo | Patients with NASH | 19 | Not named | 2 weeks |
| Decroix 2016Crossover, placebo | Healthy men | 12 | Not named, 903 mg | – |
| Campbell 2016Crossover, placebo | Healthy young adults | 9 | Not named | 6 weeks |
| Kamei 2016RCT, active or other control | Adults receiving influenza vaccination | – | Not named | – |
| Yoon 2016RCT, placebo | Photo-aged Korean women | – | Not named | 24 weeks |
| Delost 2016Other | College students | – | Not named | – |
| Neshatdoust 2016RCT, active or other control | Older adults | – | Not named | 12 weeks |
| Sansone 2015RCT, placebo | Healthy middle-aged adults | 100 | Not named, 900 mg | 4 weeks |
| Mastroiacovo 2015RCT, placebo | Cognitively intact elderly adults | 90 | Not named, 993 mg | 8 weeks |
| Ottaviani 2015RCT, placebo | Healthy adults aged 35-55 | 74 | Not named, 2,000 mg | 12 weeks |
| Rostami 2015RCT, placebo | Adults with type 2 diabetes and hypertension | 60 | Not named | 8 weeks |
| Ibero-Baraibar 2015RCT, placebo | Overweight or obese middle-aged adults | 47 | Not named, 1,400 mg | 4 weeks |
| Theunissen 2015Non-randomised controlled | Healthy volunteers | 42 | Dark chocolate 86% cocoa | – |
| Heiss 2015RCT, placebo | Healthy young and elderly men | 42 | Not named, 900 mg | 2 weeks |
| Rodriguez-Mateos 2015Pharmacokinetic | Healthy young and elderly men | 40 | Not named | – |
| Massee 2015RCT, placebo | Healthy young adults | 40 | Not named, 250 mg | 4 weeks |
| McFarlin 2015Crossover, placebo | Young women of varied BMI | 24 | Not named, 12,700 mg | 4 weeks |
| Koli 2015RCT, active or other control | Adults with mild hypertension | 22 | Not named | 8 weeks |
| Hammer 2015Crossover, placebo | Patients with peripheral artery disease | 21 | Flavonoid-rich dark chocolate, 50,000 mg | – |
| Grassi 2015Crossover, placebo | Healthy adults | 20 | Not named | 1 weeks |
| Appleton 2015RCT, active or other control | Healthy volunteers | 20 | Dark chocolate | – |
| Lamport 2015Crossover, placebo | Healthy older adults aged 50-65 | 18 | Not named | – |
| Basu 2015Crossover, placebo | Obese adults with type 2 diabetes | 18 | Not named | – |
| Rodriguez-Mateos 2015Crossover, placebo | Healthy adults | 15 | Not named | – |
| Patel 2015Crossover, placebo | Moderately trained men | 9 | Not named | 2 weeks |
| Ishikawa 2015Other | Healthy volunteers | 7 | Not named | – |
| Sarriá 2015Crossover, placebo | Normo- and hypercholesterolemic adults | – | Not named | – |
| Rull 2015RCT, placebo | Men with pre-hypertension or mild hypertension | – | Not named | 6 weeks |
| Tranquilli 2014Single-arm or open-label | Healthy pregnant women, term gestation | 100 | Not named, 30,000 mg | – |
| Parsaeyan 2014RCT, active or other control | Adults with type 2 diabetes | 100 | Not named, 20,000 mg | 6 weeks |
| Mogollon 2014RCT, placebo | Women with fair skin | 74 | High-flavanol chocolate, 30,000 mg | 12 weeks |
| von Känel 2014RCT, placebo | Healthy men aged 20-50 | 65 | Flavonoid-rich dark chocolate, 50,000 mg | – |
| Terai 2014RCT, active or other control | Glaucoma patients and matched controls | 60 | Flavonoid-rich dark chocolate | – |
| Pereira 2014RCT, active or other control | Healthy young adults | 60 | Not named, 10,000 mg | 4 weeks |
| Nickols-Richardson 2014RCT, active or other control | Overweight or obese premenopausal women | 60 | Not named | 18 weeks |
| Al Sunni 2014Non-randomised controlled | Medical students | 60 | Not named | 2 weeks |
| Ibero-Baraibar 2014RCT, placebo | Middle-aged overweight or obese adults | 50 | Cocoa extract, 1,400 mg | 4 weeks |
| Sarriá 2014RCT, active or other control | Healthy and hypercholesterolaemic adults | 44 | Fibre-rich cocoa product, 30,000 mg | 4 weeks |
| Martínez-López 2014Non-randomised controlled | Healthy and mildly hypercholesterolaemic adults | 44 | Soluble cocoa product, 15,000 mg | 4 weeks |
| Alleyne 2014Crossover, placebo | Hypertensive and normotensive adults | 36 | Not named, 5,000 mg | – |
| West 2014Crossover, placebo | Overweight middle-aged adults | 30 | Not named, 22,000 mg | 4 weeks |
| Akyol 2014RCT, active or other control | Healthy adults | 25 | Not named | – |
| Loffredo 2014RCT, active or other control | Patients with peripheral artery disease | 20 | Not named, 40,000 mg | – |
| Horn 2014Crossover, placebo | Coronary artery disease patients | 16 | Cocoa flavanols, 750 mg | 4 weeks |
| Stellingwerff 2014Crossover, placebo | Male cyclists | 16 | Cocoa-enriched dark chocolate | – |
| Caperton 2014RCT, placebo | Men with history of acne | 14 | Not named | 1 weeks |
| Esser 2014RCT, active or other control | Overweight men aged 45-70 | – | High flavanol chocolate | 4 weeks |
| Wirtz 2014Non-randomised controlled | Humans, details not in abstract | – | Not named | – |
| Brickman 2014RCT, active or other control | Healthy adults aged 50-69 | – | Not named | 13 weeks |
| Crescenti 2013RCT, active or other control | Adults with cardiovascular risk factors | 214 | Not named, 6,000 mg | 2 weeks |
| Esin 2013RCT, active or other control | Pregnant women with non-reactive NST | 180 | Bitter chocolate | – |
| Neufingerl 2013RCT, placebo | Healthy men and women aged 40-70 | 152 | Cocoa drink | 4 weeks |
| Buscicchio 2013RCT, active or other control | Healthy pregnant women | 100 | Not named, 30,000 mg | – |
| Sorond 2013RCT, placebo | Older adults with vascular risk factors | 60 | Not named | 4 weeks |
| Mogollon 2013RCT, placebo | Healthy pregnant women | 44 | High-flavanol chocolate, 20,000 mg | 12 weeks |
| Ostertag 2013Crossover, placebo | Healthy adults | 42 | Flavan-3-ol-enriched dark chocolate | – |
| Judelson 2013Crossover, placebo | Healthy young men | 24 | Cocoa-based beverage with theobromine | – |
| d'El-Rei 2013Single-arm or open-label | Treated hypertensive adults | 21 | Dark chocolate, 75,000 mg | 1 weeks |
| Llorach 2013RCT, active or other control | Adults at high cardiovascular risk | 20 | Not named, 40,000 mg | 4 weeks |
| Theunissen 2013Non-randomised controlled | Healthy breath-hold divers | 20 | Not named | – |
| Vázquez-Agell 2013RCT, active or other control | Healthy volunteers | 18 | Not named, 40,000 mg | – |
| Calderón-Garcidueñas 2013Single-arm or open-label | Urban Mexico City children | 18 | Dark cocoa, 30,000 mg | 1 weeks |
| Di Renzo 2013Single-arm or open-label | Normal weight obese women | 15 | Dark chocolate 70% cocoa, 100,000 mg | 1 weeks |
| Vitaglione 2013Crossover, placebo | Healthy volunteers | 12 | Cocoa polyphenol extract in cocoa-nut cream | – |
| Mellor 2013Crossover, placebo | Adults with type 2 diabetes | 10 | Not named | – |
| Pruijm 2013Non-randomised controlled | Healthy volunteers | 10 | Dark chocolate 70% cocoa | – |
| Peschek 2013Crossover, placebo | Endurance-trained athletes | 8 | Cocoa flavanol beverage, 700 mg | – |
| Taub 2013Single-arm or open-label | Patients with heart failure and type 2 diabetes | 5 | Epicatechin-rich cocoa | 13 weeks |
| Pase 2013RCT, placebo | Healthy middle-aged adults | – | Dark chocolate drink mix, 500 mg | 4 weeks |
| Netea 2013Single-arm or open-label | Healthy volunteers | – | Not named | – |
| Ramirez-Sanchez 2013Single-arm or open-label | Patients with type 2 diabetes and heart failure | – | Epicatechin-rich cocoa | 13 weeks |
| Chan 2012RCT, active or other control | Children aged 10-12 | 194 | Not named, 7,000 mg | 7 weeks |
| Tey 2012RCT, active or other control | Healthy adults | 118 | Not named | 12 weeks |
| Di Renzo 2012RCT, active or other control | Healthy pregnant women | 90 | Not named, 30,000 mg | – |
| Martin 2012RCT, active or other control | Healthy adults, varying trait anxiety | 90 | Not named | 2 weeks |
| Desideri 2012RCT, placebo | Older adults with mild cognitive impairment | 90 | Not named, 990 mg | 8 weeks |
| Camfield 2012RCT, placebo | Healthy middle-aged adults | 63 | Not named, 500 mg | 4 weeks |
| Nanetti 2012Single-arm or open-label | Healthy women and men | 50 | Not named, 50,000 mg | 3 weeks |
| Buscicchio 2012Single-arm or open-label | Healthy pregnant women | 50 | Not named | – |
| Tynkkynen 2012RCT, active or other control | Healthy adults | 45 | Not named | 3 weeks |
| Sarriá 2012Crossover, placebo | Healthy adults | 44 | Soluble cocoa products | 4 weeks |
| Khan 2012Crossover, placebo | High cardiovascular risk adults | 42 | Not named, 40,000 mg | 4 weeks |
| Almoosawi 2012Crossover, placebo | Overweight and lean women | 42 | Not named, 20,000 mg | 4 weeks |
| Carnevale 2012RCT, active or other control | Healthy subjects and smokers | 40 | Not named, 40,000 mg | – |
| Wolz 2012Crossover, placebo | Parkinson's disease patients | 26 | Not named, 200,000 mg | – |
| De Gottardi 2012RCT, placebo | Patients with cirrhosis and portal hypertension | 22 | Not named | – |
| Nogueira 2012Single-arm or open-label | Adults with stage 1 hypertension and excess weight | 22 | Dark chocolate 70% cocoa, 50,000 mg | 4 weeks |
| Flammer 2012RCT, placebo | Patients with heart failure | 20 | Not named | 4 weeks |
| Stote 2012Crossover, placebo | Obese adults at risk of insulin resistance | 20 | Not named, 900 mg | 1 weeks |
| Martin 2012Single-arm or open-label | Healthy adults by chocolate preference | 20 | Dark chocolate, 50,000 mg | 1 weeks |
| Fisher 2012Single-arm or open-label | Healthy older adults | 19 | Flavonoid-rich cocoa | – |
| Rasyid 2012RCT, placebo | Junior 800 m runners | 16 | Chocolate bean extract | 2 weeks |
| Rodriguez-Mateos 2012Pharmacokinetic | Healthy volunteers | 15 | Not named | – |
| Lettieri-Barbato 2012Crossover, placebo | Healthy volunteers | 15 | Not named, 100,000 mg | – |
| Davison 2012Crossover, placebo | Healthy men | 14 | Not named, 100,000 mg | – |
| Grassi 2012Crossover, placebo | Healthy young adults | 12 | Not named, 100,000 mg | 0 weeks |
| Taub 2012Single-arm or open-label | Adults with type 2 diabetes and heart failure | 5 | Not named | 13 weeks |
| Sánchez-González 2012Pharmacokinetic | Healthy volunteers | 5 | Not named, 40,000 mg | – |
| Kim 2012RCT, active or other control | Medical personnel on night shifts | – | Not named | – |
| Ottaviani 2012Pharmacokinetic | Healthy adults | – | Standardized flavanol cocoa | – |
| Actis-Goretta 2012Pharmacokinetic | Healthy adults | – | Not named | – |
| Zubair 2011Non-randomised controlled | Healthy adult volunteers on aspirin | 65 | Not named, 18,750 mg | – |
| Njike 2011Crossover, placebo | Overweight adults, BMI 25-35 | 44 | Not named | 6 weeks |
| Loffredo 2011RCT, active or other control | Smokers and healthy subjects | 40 | Not named, 40,000 mg | – |
| Sudarma 2011RCT, active or other control | Prehypertensive employees | 32 | Not named, 30,000 mg | 2 weeks |
| Field 2011Crossover, placebo | Healthy young adults | 30 | Not named | – |
| Piehowski 2011RCT, active or other control | Overweight premenopausal women | 26 | Not named | 18 weeks |
| Monahan 2011Crossover, placebo | Healthy older adults | 23 | Not named, 26,000 mg | – |
| Tzounis 2011Crossover, placebo | Healthy volunteers | 22 | Not named | 4 weeks |
| Allgrove 2011Crossover, placebo | Active men | 20 | Not named, 80,000 mg | 2 weeks |
| Westphal 2011Crossover, placebo | Healthy adults | 18 | Not named | – |
| Sørensen 2011RCT, active or other control | Healthy normal-weight young men | 16 | Dark chocolate, 100,000 mg | – |
| Desch 2010RCT, active or other control | Prehypertension patients with high CV risk | 102 | Not named | 13 weeks |
| Davison 2010RCT, active or other control | Adults with untreated mild hypertension | 52 | Not named | 6 weeks |
| van den Bogaard 2010Crossover, placebo | Adults with mildly raised blood pressure | 42 | Not named | 3 weeks |
| Scholey 2010Crossover, placebo | Healthy adults | 30 | Not named, 994 mg | – |
| Berry 2010Crossover, placebo | Overweight/obese adults, cocoa flavanol drink | 21 | Not named, 701 mg | – |
| Spadafranca 2010Non-randomised controlled | Healthy adults, dark vs white chocolate | 20 | Not named | 2 weeks |
| Heiss 2010Crossover, placebo | Patients with coronary artery disease | 16 | Not named, 750 mg | 4 weeks |
| Almoosawi 2010RCT, active or other control | Overweight and obese adults | 14 | Not named | 2 weeks |
| Massolt 2010RCT, active or other control | Young healthy women | 12 | Not named | – |
| Mellor 2010Crossover, placebo | Adults with type 2 diabetes | 12 | Not named, 45,000 mg | 8 weeks |
| Llorach-Asunción 2010Single-arm or open-label | Healthy adults | 10 | Not named | – |
| Sathyapalan 2010Crossover, placebo | Chronic fatigue syndrome patients | 10 | Not named | 8 weeks |
| Ritter 2010Pharmacokinetic | One healthy volunteer | 1 | Not named | – |
| Urpi-Sarda 2009RCT, active or other control | Adults at high cardiovascular risk | 42 | Not named, 40,000 mg | 4 weeks |
| Monagas 2009RCT, active or other control | Older adults at high cardiovascular risk | 42 | Not named, 40,000 mg | 4 weeks |
| Shiina 2009RCT, active or other control | Healthy young men | 39 | Not named, 45,000 mg | 2 weeks |
| Williams 2009RCT, active or other control | Healthy adults, UV photoprotection | 30 | Not named, 20,000 mg | 12 weeks |
| Martin 2009Single-arm or open-label | Healthy adults with low or high anxiety trait | 30 | Not named | 2 weeks |
| Llorach 2009Crossover, placebo | Healthy volunteers | 10 | Not named | – |
| Ried 2009RCT, active or other control | Adults with prehypertension | – | Not named, 50,000 mg | 12 weeks |
| Crews 2008RCT, placebo | Healthy cognitively intact older adults | 101 | Not named | 6 weeks |
| Faridi 2008Crossover, placebo | Overweight adults | 45 | Not named | – |
| Balzer 2008RCT, active or other control | Medicated diabetic patients | 41 | Not named, 963 mg | 4 weeks |
| Sorond 2008RCT, active or other control | Healthy older adults | 34 | Not named | 2 weeks |
| Hamed 2008Single-arm or open-label | Healthy volunteers | 28 | Not named | 1 weeks |
| Muniyappa 2008Crossover, placebo | Adults with essential hypertension | 20 | Not named, 900 mg | 2 weeks |
| Grassi 2008Crossover, placebo | Hypertensive adults with impaired glucose tolerance | 19 | Not named, 100,000 mg | 2 weeks |
| Davison 2008RCT, active or other control | Overweight and obese adults | – | Not named, 902 mg | 12 weeks |
| Stark 2008Pharmacokinetic | Healthy volunteers | – | Not named | – |
| Macht 2007RCT, active or other control | Healthy adults, induced negative mood | 161 | Not named | – |
| Baba 2007RCT, placebo | Normo- and mildly hypercholesterolemic adults | 160 | Not named | 4 weeks |
| Taubert 2007RCT, active or other control | Adults with prehypertension or stage 1 hypertension | 44 | Not named | 18 weeks |
| Baba 2007RCT, active or other control | Normo- and mildly hypercholesterolemic adults | 25 | Not named, 26,000 mg | 12 weeks |
| Flammer 2007RCT, placebo | Heart transplant recipients | 22 | Not named, 40,000 mg | – |
| Roura 2007Crossover, placebo | Healthy volunteers | 21 | Not named, 40,000 mg | – |
| Neukam 2007Crossover, placebo | Healthy women | 10 | Not named | – |
| Heiss 2007Single-arm or open-label | Smokers with endothelial dysfunction | 6 | Flavanol-rich cocoa drink, 918 mg | 1 weeks |
| Tomas-Barberan 2007Crossover, placebo | Healthy volunteers | – | Flavonoid-enriched cocoa powder | – |
| Chan 2007RCT, active or other control | Adults, dark vs milk chocolate | – | Not named | – |
| Farouque 2006RCT, placebo | Adults with coronary artery disease | 40 | Not named, 444 mg | 6 weeks |
| Macht 2006Non-randomised controlled | Healthy normal-weight women | 37 | Not named | – |
| Roura 2006Crossover, placebo | Healthy volunteers | 36 | Not named | – |
| Fisher 2006Non-randomised controlled | Healthy young and older adults | 34 | Flavanol-rich cocoa | 1 weeks |
| Wang-Polagruto 2006RCT, placebo | Hypercholesterolemic postmenopausal women | 32 | Not named | 6 weeks |
| Chlup 2006Single-arm or open-label | Healthy volunteers | 20 | Not named | – |
| Francis 2006Other | Healthy young adults | 16 | Not named, 150 mg | 1 weeks |
| Singh 2006Crossover, placebo | Trained and sedentary men | 16 | Not named | 1 weeks |
| Tokuda 2006Single-arm or open-label | Tube-fed patients with copper deficiency | 13 | Not named | – |
| Schroeter 2006Other | Healthy male adults | – | Flavanol-rich cocoa | – |
| Heinrich 2006RCT, placebo | Healthy women | – | Not named | 12 weeks |
| Grassi 2005Crossover, placebo | Never-treated hypertensive adults | 20 | Not named, 100,000 mg | 2 weeks |
| Vlachopoulos 2005Crossover, placebo | Healthy young adults | 17 | Not named, 100,000 mg | – |
| Grassi 2005Crossover, placebo | Healthy adults | 15 | Not named, 100,000 mg | 2 weeks |
| Heiss 2005Crossover, placebo | Smokers | 11 | Not named | – |
| Ito 2005Pharmacokinetic | Nine healthy volunteers | 9 | Not named | – |
| Zhu 2005Single-arm or open-label | Healthy adults | 8 | Not named | – |
| Mursu 2004RCT, placebo | Healthy nonsmoking adults | 45 | Not named, 75,000 mg | 3 weeks |
| Smit 2004RCT, placebo | Healthy adults | 42 | Not named, 11,600 mg | – |
| Engler 2004RCT, placebo | Healthy adults | 21 | Not named, 46,000 mg | 2 weeks |
| Wiswedel 2004Crossover, placebo | Healthy volunteers | 20 | Not named | – |
| de O G Mendonça 2003RCT, active or other control | Calcium stone-forming patients | 58 | Not named | 0 weeks |
| Murphy 2003RCT, placebo | Healthy adults | 32 | Not named, 234 mg | 4 weeks |
| Innes 2003RCT, placebo | Healthy volunteers | 30 | Not named, 100,000 mg | – |
| Fisher 2003RCT, active or other control | Healthy adults | 27 | Flavanol-rich cocoa, 821 mg | 1 weeks |
| Record 2003Crossover, placebo | Healthy volunteers | 18 | Not named | 4 weeks |
| Verakaki 2003Other | Healthy volunteers, dental plaque pH | 14 | Not named, 15,000 mg | – |
| Rios 2003Pharmacokinetic | Healthy adults | 11 | Not named, 80,000 mg | – |
| Brand-Miller 2003Other | Healthy lean young adults | 10 | Not named | – |
| Taubert 2003Other | Elderly adults with isolated systolic hypertension | – | Not named | – |
| Serafini 2003Other | Unclear | – | Not named | – |
| Mathur 2002Single-arm or open-label | Healthy adults | 25 | Not named, 67,850 mg | 6 weeks |
| Pearson 2002RCT, active or other control | Healthy adults | 16 | Not named | – |
| Rios 2002Pharmacokinetic | Healthy adults | 6 | Not named | – |
| Holt 2002Pharmacokinetic | Healthy adults | 5 | Not named | – |
| Pitroipa 2002Other | Rural residents, Cote d'Ivoire | – | Not namedOn the skin | – |
| Wan 2001Crossover, placebo | Healthy adults | 23 | Not named, 38,000 mg | – |
| Osakabe 2001Non-randomised controlled | Healthy male volunteers | 15 | Not named, 36,000 mg | 2 weeks |
| Schramm 2001Crossover, placebo | Healthy adults | 10 | Not named | – |
| Wakugami 2000Single-arm or open-label | Enteral nutrition patients with copper deficiency | 86 | Not named | 6 weeks |
| Samman 2000RCT, active or other control | Mildly hypercholesterolaemic adults | 42 | Not named | 12 weeks |
| Rein 2000Non-randomised controlled | Healthy adults | 30 | Not named | – |
| Rein 2000Single-arm or open-label | Healthy adults | – | Not named, 80,000 mg | – |
| Wang 2000Other | Healthy adults | – | Not named | – |
| Rein 2000Other | Healthy adults | – | Not named | – |
| Baba 2000Pharmacokinetic | Healthy male volunteers | – | Not named | – |
| Richelle 1999Pharmacokinetic | Healthy male volunteers | 8 | Nestle Noir | – |
| Baron 1999RCT, active or other control | Healthy young adults | – | Not named | – |
| Wakigami 1999Single-arm or open-label | Patients on long-term enteral nutrition | – | Not named | – |
| Hurrell 1999Other | Healthy adults | – | Not named | – |
| Strandberg 1999Other | Adults at Christmas season | – | Not named | – |
| Francois 1998RCT, active or other control | Healthy lactating women | 14 | Not named | – |
| Marcus 1997RCT, placebo | Women with chronic headache | 63 | Not named | – |
| Chen 1996Crossover, placebo | Male student recreational runners | 16 | Not named | – |
| Mumford 1996Pharmacokinetic | Healthy adults | 7 | Not named | – |
| Nguyen 1994Non-randomised controlled | Healthy adults | 10 | Not named, 100,000 mg | – |
| Michener 1994RCT, placebo | Chocolate cravers | – | Not named | – |
| Mustad 1993RCT, active or other control | Healthy young men | 15 | Not named | 4 weeks |
| Hesse 1993Other | Healthy adults | – | Not named | – |
| Nakagawa 1993Single-arm or open-label | Tube-fed handicapped children with zinc deficiency | – | Not named | – |
| Gibb 1991RCT, placebo | Migraine patients who believe chocolate triggers attacks | 20 | Not named | – |
| Denke 1991RCT, active or other control | Middle-aged men | 10 | Not named | 3 weeks |
| Lee 1989Crossover, placebo | Adults with lactose intolerance | 35 | Not named | – |
| Balcke 1989Crossover, placebo | Male adults | 6 | Not named, 50,000 mg | – |
| Peatfield 1988Other | Migraine patients | 6 | Not named, 100,000 mg | – |
| Yankell 1988Other | Humans, not stated | – | Not named | – |
| Murphy 1988RCT, active or other control | Patients with esophagitis | – | Not named | – |
| Hirst 1987Other | Social drinkers, abstainers to heavy | 120 | Not named | – |
| van Herpen 1986Other | Adults, not stated | – | Not named | – |
| Lagemann 1985Other | Children incl. former stone formers | 51 | Not named | 0 weeks |
| Shively 1985Pharmacokinetic | Healthy men | 12 | Not named | 1 weeks |
| Carlson 1985Other | Healthy women | – | Not named | – |
| Popov 1983Non-randomised controlled | Test subjects, simulated emergency | – | Not named, 300,000 mg | 1 weeks |
| Popov 1983Single-arm or open-label | Healthy test subjects, emergency diet | – | Not named, 300,000 mg | – |
| Brinkley 1981Single-arm or open-label | Healthy volunteers | 8 | Not named | – |
| Palenik 1979Other | Humans, not stated | – | Not named | – |
| Osztrics 1978Other | Humans, not stated | – | Not named | – |
| Wright 1975Crossover, placebo | Normal adult subjects | 9 | Not named | – |
| Mackie 1974Other | Acne patients | – | Not named | – |
| Czok 1974Other | Humans, not stated | – | Not named | – |
| Moffett 1974Crossover, placebo | Migraine sufferers who link headache to chocolate | – | Not named | – |
| Lambermont 1973Other | Patients for small bowel radiology | – | Not named | – |
| Babka 1973Other | Humans, not stated | – | Not named | – |
| Maslansky 1970Non-randomised controlled | People with acne vulgaris | – | Not named | – |
| Minkin 1970Other | Acne vulgaris patients | – | Not named | – |
| Fulton 1969Other | People with acne vulgaris | – | Not named | – |
| Bartels 1969Other | Humans, not stated | – | Not named | – |
| Keiner 1969Other | Not stated | – | Not named | – |
| Nestel 1966Other | Two men on controlled diets | 2 | Not named | – |
| PERSIDSKII 1955Other | Humans, gastric secretion | – | Not named | – |
| GOUNELLE 1954Other | Humans, liver function tests | – | Not named | – |
| QUENSEL 1954Other | Humans, dental caries | – | Not named | – |
| ROUSSEL 1953Other | Children, liver tests | – | Not named | – |
| 1951Other | Humans, calcium and nitrogen balance | – | Not named | – |
| REYNOLDS 1950Other | Humans, protein utilisation | – | Not named | – |
| BRICKER 1949Other | Women, calcium and nitrogen balance | – | Not named | – |
Safety
What's known about safety
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In trials
Generally well tolerated. A review of 35 trials found stomach complaints and nausea in about 1 in 100 people taking cocoa. One trial gave up to 2,000 mg of cocoa flavanols a day for 12 weeks and reported only mild side effects.
Ried 2017, Cochrane review of 35 trials; Ottaviani 2015, 12-week trial
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In the UK
Cocoa and chocolate are ordinary foods. One cocoa extract, made from defatted cocoa powder, is an authorised novel food in Great Britain, and its label must say not to take more than 600 mg of polyphenols a day.
FSA register of regulated products, extract of defatted cocoa powder, Oct 2026
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Check first
Cocoa contains caffeine, which counts towards the 200 mg a day limit advised in pregnancy, and cocoa products haven't been well studied in pregnancy. Large amounts may add to the side effects of theophylline. Speak to a pharmacist or doctor first if either applies to you.
MedlinePlus caffeine and theophylline pages; Latif 2018, review of chocolate in pregnancy
How we built this
Where these studies come from
We list every published study of cacao in people. Cocoa, cocoa flavanol extracts and dark chocolate count as cacao on its own; milk chocolate and chocolate milk count as a blend. Cocoa butter, cocoa husk, pod and pulp are left out, as are studies that used chocolate only as a taste or to carry something else. This first version is built from each study's summary; full-paper checks come next.
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We search
PubMed, the world's main library of medical research, for every paper on L-theanine.
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We keep studies in people
Lab and animal work is counted but left out of the list, because it doesn't tell you what happens in people.
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We note the basics
Who took part, how many, how much and for how long, from each study's published summary. A second check corrects what the first read gets wrong.
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We read them in full
Results appear once we've read the whole paper and checked every number. The date at the top shows when this entry was last updated.
Download the study list
Every study in people as a spreadsheet, 439 rows, free to reuse with a link back.
Versions
Each update to the data gets a new version number, so you can tell what changed and when.
See every version
1.0 · 24 Oct 2026. First release. Every published study giving cacao on its own to people is listed from its summary. None is read in full yet.