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Blood Flow

Blood flow is a measure of blood circulation, and is independent of blood pressure. It can be increased either by reducing artherosclerotic plaque, or producing nitric oxide.

Research analysis led by Kamal Patel.
All content reviewed by the Examine.com Team. Published:
Last Updated:

Human Effect Matrix

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what supplements affect blood flow
Grade Level of Evidence
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.
grade-a Cocoa Extract 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.
grade-b Pycnogenol Notable Very High See all 3 studies
An improvement in nitric oxide dependent blood flow appears to occur following procyanidin supplementation which has been noted in both unhealthy persons as well as healthy controls; there does not appear to be a per se hypotensive effect either.
grade-b Arginine Minor Low See all 6 studies
May increase blood flow secondary to activating nitric oxide, but due to the unreliability of increasing nitric oxide there is also unreliability in how arginine increases blood flow
grade-b Centella asiatica  
grade-b Coenzyme Q10  
grade-b Ginkgo biloba  
grade-b Green Tea Catechins  
grade-b Vitamin C  
grade-b Vitamin E  
grade-b Fish Oil  
grade-c Grape Seed Extract  
grade-c Hesperidin  
grade-c Taurine  
grade-c Alpha-Lipoic Acid  
grade-c Caffeine  
grade-c Citrulline  
grade-c Curcumin  
grade-c Dehydroepiandrosterone  
grade-c L-Carnitine  
grade-c Melatonin  
grade-c Panax ginseng  
grade-c Psyllium  
grade-c Resveratrol  
grade-c Astaxanthin  
grade-c Chromium  
grade-c Conjugated Linoleic Acid  
grade-c Ganoderma lucidum  
grade-c Garlic  
grade-c Grapefruit  
grade-c Marijuana  
grade-c Nitrate  
grade-c Policosanol  
grade-c Red Clover Extract  
grade-c Trimethylglycine  
grade-c Vitamin B3 (Niacin)  
grade-c Whey Protein  
grade-c Zinc  
grade-d Artichoke Extract  
grade-d Creatine  
grade-d Black Cohosh  

All comparative evidence is now gathered in our ​A-to-Z Supplement Reference.

The evidence for each separate supplement is still freely available ​here.