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Japanese Knotweed

Japanese Knotweed, or Polygonum Cuspidatum, is a Traditional Chinese Medicine used for circulation and heart health. It is a very good source of resveratrol, and most benefits of Japanese Knotweed may actually just be benefits of Resveratrol.

Our evidence-based analysis on japanese knotweed features 55 unique references to scientific papers.

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Summary of Japanese Knotweed

Primary information, health benefits, side effects, usage, and other important details

Polygonum Cuspidatum var. Japonicus is the species of plant most commonly referred to as Japanese Knotweed. This plant is an invasive species yet has been used traditionally in Chinese and Japanese medicine for its benefits on gastrointestinal health and circulatory health (among some other claims such as cancer prevention). Composition analysis of Japanese Knotweed reveals it to be a vessel for Resveratrol (as well as a few other compounds structurally similar to resveratrol and may act in the same way) and anthraquinone compounds that possess slight laxative effects; like Senna root but less potent.

Most of the effects of Japanese Knotweed can be traced back to either the stilbenes (resveratrol) or the anthraquinones (emodin) for the circulatory and gastrointestinal help, respectively.

Most research on Japanese Knotweed has been pertaining to either suppressing its invasive tendencies, or controlling it to become a large scale producer of Resveratrol for medical or supplemental usage. Limited trials have been conducted in humans, but it appears to have similar effects to resveratrol due to the resveratrol content.

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How to Take

Recommended dosage, active amounts, other details

The only current human study used Japanese Knotweed at 200mg daily and standardized to 40mg Resveratrol which was effective.

Although there are other bioactives in Japanese Knotweed, it may be prudent to dose it in accordance to the dosing guidelines on the resveratrol page.

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Human Effect Matrix

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The Human Effect Matrix summarizes human studies to tell you what effects Japanese Knotweed has on your body, how much evidence there is, and how strong these effects are.

Full details are available to Examine members.
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-c Notable - See study
The study in question measured nF-kB activity and noted a 25% decrease, which is somewhat novel (not a common measurement) and to quite a large degree; may be related to the resveratrol or stilbene content
grade-c Minor - See study
Appears to reduce oxidative biomarkers, requires more evidence to gauge potency and reliability thereof
grade-c Minor - See study
A decrease in TNF-a has been noted following oral consumption of japanese knotweed
grade-c - - See study
Blood glucose appears to be unaffected following ingestion of Japanese knotweed in otherwise healthy lean persons
grade-c - - See study
No significant influence on HDL-C in otherwise healthy lean persons
grade-c - - See study
No significant alterations in fasting insulin levels seen with treatment
grade-c - - See study
Insulin sensitivity is unaffected in otherwise healthy lean persons given this supplement
grade-c - - See study
LDL-C appears to be unaffected, but testing has not been conducted in metabolically unwell persons
grade-c - - See study
No significant influence on leptin in otherwise healthy and lean individuals
grade-c - - See study
No significant alterations in cholesterol seen with Japanese Knotweed ingestion
grade-c - - See study
No significant influence of Japanese Knotweed on triglycerides

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Things to Note

Primary Function:

Also Known As

Polygonum Cuspidatum, Huzhang, Fleeceflower, Monkeyweed, itadori, Polygonum Japonicus, Kudzu

Do Not Confuse With

Polygonum Multiforum (different composition from a related plant), Pueraria lobata (also called Kudzu)

Goes Well With

(As a source of Resveratrol, it might be prudent to see what is synergistic with Resveratrol; by extension they are somewhat synergistic with Japanese Knotweed)

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Click here to see all 55 references.