Cocoa Extract

Cocoa extract refers to the bioactive compounds found in cocoa products. These compounds include flavanols, procyanidins and (-)-epicatechin. Though these molecules are not unique to cocoa, cocoa extract contains a particularly high level of (-)-epicatechin, compared to other plant products.

Supplementing cocoa extract or eating dark chocolate is linked to better blood flow and improved insulin sensitivity.

Preliminary research suggests (-)-epicatechin may also provide benefits for longevity by increasing blood flow and oxygenation in the brain. Though this effect has not been linked to improved memory or cognitive performance, it may play a protective role during aging. Some evidence also suggests (-)-epicatechin can help mitigate the effects of impaired mitochondria.

When (-)-epicatechin is absorbed by the body, it activates an insulin signaling pathway, which causes a mild increase in glucose uptake. Increased glucose uptake means the body is able to take in sugar from the blood more effectively. Supplementing (-)-epicatechin also increase the production of nitric oxide, a molecule that widens blood vessels and improves blood flow.

Eating about 26-40g of dark chocolate products containing at least 75% cocoa makes supplementing cocoa extract and (-)-epicatechin unnecessary. This is about 200 calories of dark chocolate, a bit less than a standard candy bar. Products low in cocoa, like milk chocolate and white chocolate, do not replace supplementation. Cocoa extract is a safe supplement that promotes circulation and effective energy production. It has great potential long-term benefits, whether the (-)-epicatechin comes from supplements or food products.

Studies show that 5-26g of dark chocolate contains 65-1,095mg of flavanols. The standard dose for cocoa flavanols is 500 – 1,000mg a day, taken with meals.

Supplementing cocoa extract can be replaced by dark chocolate consumption. The recommended amount is 25 – 40 g of dark chocolate, containing at least 85% cocoa. This is about 200 calories of dark chocolate. Milk and white chocolate do not contain enough cocoa to replace supplementation.

More research is needed to determine the optimal dose of cocoa extract.

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects cocoa extract has on your body, and how strong these effects are.

Grade	Level of Evidence [show legend]
	Robust research conducted with repeated double-blind clinical trials
	Multiple studies where at least two are double-blind and placebo controlled
	Single double-blind study or multiple cohort studies
	Uncontrolled or observational studies only

Level of Evidence ? The amount of high quality evidence. The more evidence, the more we can trust the results.	Outcome	Magnitude of effect ? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.	Consistency of research results ? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.	Notes
	Blood Flow	Notable	Very High See all 20 studies	Blood flow appears to be increased in the body very reliably as assessed by flow-mediated vasodilation (FMD) by around 2%, affecting both healthy and unhealthy people. There may also be an increase in arterial blood flow which is less reliable.
	Blood Pressure	Minor	- See all 23 studies	While not affecting everybody, there appears to be a decrease in blood pressure when assessing mildly hypertensive people; the increase in blood flow seen in healthy people is not accompanied by a decrease in blood pressure, while the xanthine (caffeine) content of chocolate products may cause a mild and transient increase in blood pressure in some subjects.
	LDL-C	Minor	Very High See all 15 studies	Cocoa products appear to be able to reduce LDL cholesterol due to their flavonoid component, with the reduction in LDL-C being mild.
	HDL-C	-	Very High See all 15 studies	While an increase of HDL-C may occur, it is both mild and infrequent so large studies and meta-analyses fail to find reliable evidence for cocoa.
	Total Cholesterol	-	Very High See all 14 studies	Although LDL-C may be decreased mildly, alterations in total cholesterol did not appear to occur; this may be due to unreliable but mild increases in HDL-C balancing out the numbers.
	Triglycerides	-	Very High See all 16 studies	The vast majority of studies assessing either dark chocolate products or isolated polyphenolics from cocoa fail to find any influence on triglycerides relative to placebos or control chocolates.
	8-isoPGF2a	Minor	Moderate See all 4 studies	This biomarker of inflammation has been noted to be reduced in two studies where the subjects were prooxidative at rest (PAD and smokers), with no influence in other studies of otherwise healthy subjects.
	General Oxidation	Minor	Moderate See all 6 studies	A potential yet unreliable decrease in biomarkers of oxidation in serum following ingestion.
	Insulin Sensitivity	Minor	Moderate See all 9 studies	Many studies have noted a minor benefit to insulin sensitivity in both healthy subjects and diabetics, likely due to a transient increase of glucose uptake into tissue (a more 'bandaid' effect rather than a curative one).
	Attention	-	Very High See all 3 studies	In assessing the effects of cocoa on mood states, attention does not appear to be significantly altered when compared to placebo.
	Blood Glucose	-	High See all 10 studies	It is possible that the improvement in insulin sensitivity could beneficially influence blood glucose, but most studies assessing diabetic or healthy subjects find no difference in fasting glucose concentrations. The increase in serum glucose in response to an oral glucose tolerance test may be attenuated somewhat.
	C-Reactive Protein	-	Very High See all 8 studies	Most studies assessing cocoa flavanols do not find reliable reductions in C-reactive protein when compared to placebo or control treatments.
	Heart Rate	-	Very High See all 10 studies	Cocoa and the main constituent (-)-epicatechin do not appear to have an appreciable effect on heart rate at rest or during exercise when compared to placebo.
	Insulin	-	High See all 9 studies	Despite improvements in insulin sensitivity, only one study has noted a reduction in fasting insulin in diabetics while other studies (in diabetics and healthy subjects) do not notice any significant alterations in insulin concentrations.
	Noradrenaline	-	Very High See all 3 studies	Peripheral concentrations of noradrenaline do not appear to be influenced by supplementation of cocoa.
	Oxidation of LDL	-	High See all 5 studies	The majority of evidence does not find a significant alteration in the rate of LDL oxidation with cocoa or its isolated flavanols relative to placebo.
	Weight	-	Very High See all 10 studies	Beyond one study suggesting benefits, the majority of studies including cocoa flavanols in the diet have failed to note significant weight loss compared to isocaloric controls.
	Photoprotection	Notable	- See all 3 studies	Mixed results reported. Two randomized, controlled trials report significant protection from UV-induced skin damage with 320-326mg/day cocoa flavanols over 6-24 week time periods. In contrast, another study using high flavanol chocolate (600mg flavanols) over a period of weeks failed to note any increase in the resistance of the skin towards reddening in response to light.
	Platelet Aggregation	Notable	Very High See all 5 studies	Both acute and prolonged ingestion of reasonable levels of cocoa flavonoids (500mg or more) appear to reduce the aggregation of platelets, although the potency is lesser than that of a baby aspirin (81mg).
	Adrenaline	Minor	Moderate See 2 studies	Mixed evidence as to whether serum adrenaline can be reduced in serum following cocoa ingestion prior to an acute stressor.
	Arterial Stiffness	Minor	Very High See 2 studies	Mixed evidence as to whether cocoa flavanols can decrease arterial stiffness in otherwise healthy adults, with the one study coming back positive being conducted in overweight adults
	Blood Viscosity	Minor	- See study	One study measuring blood viscosity has noted a decrease associated with cocoa flavanols, likely associated with the reduction in platelet aggregation.
	Calmness	Minor	- See study	One study using relatively high doses of cocoa flavanols (500mg) found an increased rate of calmness and well being when compared to placebo in otherwise healthy subjects.
	Cerebral Blood Flow	Minor	- See study	Cerebral blood flow during cognitive testing in youth can be increased from 170mg cocoa flavanols, although may not coexist with increases in cognition.
	Cerebral Oxygenation	Minor	- See study	The rate of cerebral oxygenation in youth subject to a cognitive task appeared to be increased alongside increased cerebral blood flow, despite no acute benefits to cognition.
	Hepatic Venous Pressure Gradient	Minor	- See study	An improvement in the HPVG has been noted in subjects with liver cirrhosis given cocoa flavanols.
	Insulin Secretion	Minor	Moderate See 2 studies	Mixed evidence as to whether cocoa flavanols can increase insulin secretion, with the positive result coming from a very high dose (1,000mg flavanols) in hyperglycemic subjects.
	Lipid Peroxidation	Minor	Moderate See all 4 studies	Decreases in lipid peroxidation (assessed by serum MDA) have been noted in oxidative states such as exercise, but have not been noted in resting states after cocoa flavanol ingestion.
	Nitric Oxide	Minor	Moderate See all 5 studies	There is mixed evidence in both smokers and subjects with peripheral vascular disease (two states of high endothelial oxidation) as to whether the inclusion of dark chocolate can increase nitric oxide levels, which would underlie improvements in blood flow.
	Skin Elasticity	Minor	Very High See 2 studies	A slight increase in skin elasticity has been noted with oral flavanol supplementation in women, noted in the temple but not arm.
	Symptoms of Peripheral Vascular Disease	Minor	Moderate See 2 studies	There is mixed evidence as to suggest benefits to peripheral vascular disease when cocoa (40-50g dark chocolate) is ingested acutely before walking tests.
	Acne	-	- See study	One study assessing the blinded intake of chocolate in subjects who reported to be acne prone found an increase in acne when chocolate was given relative to placebo.
	Adiponectin	-	- See study	No significant influence on circulating adiponectin concentrations when compared to control.
	Adrenocorticotropic Hormone	-	Very High See all 3 studies	Serum ACTH concentrations do not appear to be influenced by supplementation of cocoa.
	Aerobic Exercise	-	- See study	The performance of soccer players is unaltered in response to cocoa flavanol ingestion.
	Cell Adhesion Factors	-	Very High See all 4 studies	As a general statement, supplementation of cocoa flavanols does not appear to appreciably reduce cellular adhesion factors (ex. ICAM-1 or VCAM-1) when compared to placebos with low cocoa flavanol content.
	Cognition	-	- See study	General cognition does not appear to be acutely affected by supplementation of cocoa flavanols.
	Cortisol	-	- See all 3 studies	The increase in cortisol has been buffered in one study where stress was introduced, but otherwise cocoa does not appear to influence resting cortisol concentrations.
	Creatinine	-	Very High See 2 studies	Serum creatinine does not appear altered from supplementation of flavanols from cocoa.
	Fat Oxidation	-	Very High See all 3 studies	The rate of fat oxidation relative to carbohydrates does not appear to be altered in response to supplementation of cocoa flavanols.
	Fatigue	-	- See study	Fatigue during cognitive testing in otherwise healthy youth is not affected by supplementation of cocoa flavanols.
	HbA1c	-	- See study	HbA1c does not appear to be altered in response to cocoa flavanol ingestion.
	Homocysteine	-	- See study	Homocysteine has been found to be unaltered in response to cocoa ingestion compared to control.
	Interleukin 6	-	Very High See all 4 studies	Serum interleukin six (IL-6), a biomarker of inflammation, does not appear to be altered in response to supplementation of cocoa.
	Intraocular Pressure	-	- See study	Cocoa does not appear to reduce intraocular pressure when given to subjects with glaucoma.
	Leptin	-	- See study	No significant influence on circulating leptin concentrations when compared to control.
	Memory	-	Very High See 2 studies	In subjects with otherwise healthy cognition, the addition of cocoa flavanols to the diet does not appear to significantly increase memory retention when compared to placebo.
	Plasma Vitamin E	-	- See study	An increase in plasma vitamin E concentrations have been noted in soccer players alongside an increase in other antioxidative biomarkers, suggesting an antioxidant effect in this study.
	Portal Hypertension	-	- See study	While cocoa flavanol showed benefit to subjects with liver cirrhosis, it was unrelated to reductions in portal (liver) hypertension.
	Skin Moisture	-	Very High See all 3 studies	Oral supplementation of cocoa flavanols does not appear to significantly influence skin hydration when compared to placebo.
	Subjective Well-Being	-	Moderate See all 3 studies	While one study using high dose flavanols (250-500mg) found increased well being in subjects during cognitive testing, other studies using dark chocolate have failed to notice any benefit to self-reported well being compared to placebo.
	TNF-Alpha	-	Very High See all 3 studies	The circulating biomarker of inflammation TNF-alpha does not appear to be altered in response to supplementation from cocoa flavanols.
	Urea	-	- See study	Urea is not altered in the blood when compared to control.
	Uric Acid	-	- See study	Serum uric acid/urate seems unaltered in response to cocoa flavanol supplementation.
	Working Memory	-	Very High See 2 studies	In otherwise cognitively well subjects, working memory does not appear to be increased in response to cocoa flavanol ingestion.
	vLDL-C	-	Very High See 2 studies	vLDL-C concentrations in serum do not appear to be altered in response to supplementation of cocoa flavanols.
	Cutaneous Blood Flow	Notable	- See study	One study has found longer-term high-flavanol cocoa improves cutaneous blood flow in women.
	Exercise-Induced Oxidation	Minor	Very High See 2 studies	The increase in oxygenation during exercise can be attenuated by supplementation of cocoa flavanols taken prior to exercise.
	IL-1Ra	Minor	Moderate See 2 studies	Mixed evidence as to whether the receptor for IL-1a is reduced in amount following cocoa ingestion.
	Kidney Oxygenation	Minor	- See study	An increase in oxygenation of renal (kidney) tissue has been noted with supplementation of cocoa flavanols in otherwise healthy subjects
	Mitochondrial Protection	Minor	- See study	In subjects with diabetes-associated heart failure, low dose epicatechin (100mg) appeared to improve mitochondrial function and structure
	Anaerobic Running Capacity	-	- See study	Anaerobic exercise does not appear to be beneficially influenced by pre-exercise supplementation of cocoa flavanols in otherwise healthy subjects.
	Fat Mass	-	Very High See 2 studies	Fat mass does not appear to be influenced with supplementation of cocoa flavanols
	Fibrinogen	-	- See study	Fibrinogen concentrations do not appear altered when 100g chocolate is ingested in otherwise healthy subjects
	Food Intake	-	- See study	The inclusion of cocoa flavanols via dark chocolate does not appear to alter whole-day food intake when compared to low flavanol chocolate.
	Glucagon	-	- See study	Serum glucagon does not appear to be influenced by ingestion of cocoa flavanols.
	Interleukin 1-alpha	-	- See study	IL-1a has been found to be unaffected by supplementation of chocolate in otherwise healthy subjects
	Interleukin 1-beta	-	Very High See 2 studies	Interleukin-1B does not appear to be influenced by supplementation of cocoa flavanols
	Interleukin 10	-	- See study	Serum interleukin-10 does not appear to be influenced with supplementation of cocoa flavanols
	Lactate Production	-	- See study	The rate of lactate accumulation and production during exercise does not appear to be significantly influenced by pre-exercise supplementation of cocoa flavanols
	Lean Mass	-	- See study	Lean mass does not appear to be increased in response to supplementation of cocoa flavanols
	Liver Enzymes	-	- See study	Liver enzymes do not appear to be altered with supplementation of cocoa flavanols
	Neutrophil Activity	-	- See study	Neutrophil activity does not appear to be altered in response to cocoa flavanol supplementation
	Neutrophil Count	-	Very High See 2 studies	The overall amount of neutrophils in serum do not appear to be altered in response to cocoa flavanols
	Rate of Perceived Exertion	-	Very High See 2 studies	The rate of perceived exertion during exercise does not appear to be altered when cocoa flavanols are ingested prior to exercise.

Studies Excluded from Consideration

Note: The above rubric includes studies both on isolated (-)-epicatechin as well as cocoa products with a high flavonoid content (ie. dark chocolate), but not studies on milk or white chocolates