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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: Dec 12, 2012
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.
Notes
grade-a 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 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 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 Minor Very High See all 4 studies
Blood flow appears to be increased alongside improvements in microcirculation seen in persons with impaired venous insufficiency being treated with centella asiatica
grade-b Minor Very High See all 3 studies
Appears to increase blood flow in metabolic conditions characterized by both insufficient blood flow and an excess of oxidative stress.
grade-b
Minor
- See all 7 studies
Ginkgo biloba has shown both vasodilatory effects (via nitric oxide metabolism) and some possible constrictive effects, depending on the context of supplementation.
grade-b Minor - See study
Appears to somewhat increase blood flow
grade-b Minor Very High See all 7 studies
An increase in blood flow is seen in instances of impaired blood flow (smoking, obesity, etc.) which may be due to preservation of nitric oxide function (via reducing oxidation thereof); this is a phenomena general to antioxidants and not unique to Vitamin C
grade-b
Minor
- See all 3 studies
Similar to blood pressure, blood flow is differentially affected by vitamin E supplementation thought to be due to whether it is acting as a prooxidant or an antioxidant.
grade-b - Moderate See all 5 studies
Although there is some counter evidence to suggest an improvement of small magnitude, most evidence suggest no significant changes in blood flow
grade-c Notable Very High See 2 studies
An increase in blood flow appears to be reliable following ingestion of high dose procyanidins; this is likely the same increase seen with Pycnogenol due to the same molecules being bioactive
grade-c Notable Very High See 2 studies
An increase in blood flow has been noted in persons with metabolic impairments, and was fairly notable in the lone study due to reaching 24.5% over placebo.
grade-c Notable - See study
The improvement in blood flow seen in type 1 diabetics was sufficient to normalize to a non-diabetic control group
grade-c Minor Very High See 2 studies
May increase blood flow, although not the a remarkable degree. Possibly secondary to antioxidative effects
grade-c Minor - See study
An increase in blood flow (Flow mediated vasodilation) has been noted with caffeine.
grade-c Minor - See study
An increase in blood flow is noted with citrulline supplementation in persons with impaired blood flow
grade-c Minor Very High See 2 studies
An increase in blood flow has been noted with curcumin supplementation
grade-c Minor - See study
Possible increases in blood flow associated with DHEA supplementation
grade-c Minor - See study
Increases in blood flow appear to occur following carnitine supplementation, which may be related to the increases in nitrate
grade-c Minor - See study
Has been noted to increase blood flow at rest
grade-c Minor Very High See 2 studies
An increase in blood flow has been noted with panax ginseng supplementation
grade-c Minor - See study
Study noted an improved augmentation index by 22% alongside a reduction in blood pressure, mechanisms unknown and no reference drug for comparison.
grade-c Minor - See study
An improvement in blood flow (secondary to nitric oxide interactions) has been noted with low dose resveratrol, possibly relevant to high wine and grape product consumption
grade-c - - See study
grade-c - - See study
In persons at risk for type II diabetics, chromium supplementation failed to improve blood flow relative to placebo.
grade-c - - See study
Insufficient evidence to support changes in blood flow.
grade-c - - See study
No significant influence on blood flow noted with reishi ingestion
grade-c - Very High See 2 studies
Minimal studies have directly measured blood flow associated with garlic, and the best evidence currently suggests that basal flow mediated vasodilation is unaffected; there is likely an effect, although most studies indirectly measure blood pressure.
grade-c - - See study
No significant influence on blood flow noted
grade-c - - See study
Despite alterations in cardiac output and diastolic blood pressure, acute usage of marijuana does not appear to influence the flow of blood relative to control.
grade-c - - See study
No significant influence on blood flow in studies that use flow-mediated vasodilation
grade-c - - See study
No significant influence detected on blood flow
grade-c - Moderate See 2 studies
The reduction in arterial stiffness (increase in arterial compliance) sometimes seen with supplementation of red clover extract does not necessarily coincide with improved blood flow.
grade-c - - See study
grade-c - Very High See all 3 studies
While one study noted an increase in blood flow in subjects on medication who were given additional niacin, other studies do not find an interaction with niacin and blood flow.
grade-c - - See study
Insufficient evidence to support a role of whey protein in improving blood flow
grade-c - - See study
Blood flow does not appear to be modified with supplementation of zinc.
grade-d Minor - See study
The increase in blood flow was relatively minor in magnitude, possibly related to antioxidant effects.
grade-d Minor Very High See 2 studies
One study has found that creatine can increase blood flow to the calf and leg when combined with resistance training in healthy men. Creatine alone was found to have no effect.
grade-d - - See study
No significant influences on blood flow and vasodilation