A hot-water extract of the young shoots of wild giant knotweed (Polygonum sachalinense) from Hokkaido, made in Japan and powdered with dextrin. The named marker component is quercetin-3-rutinoside (rutin), and the reference intake is 240 mg per day. Packed in 1 kg aluminium bags, with a shelf life of 2 years unopened.
Tell us what you are developing and which documents you need. We reply from Japan within one working day with the product specification, SDS and the CoA of the current lot.
The young shoots are carefully selected and harvested from wild giant knotweed growing in Hokkaido. They are extracted with hot water, and the extract is made into a powder with dextrin in Japan. Hot water is the extraction solvent.
Step 1 · Hokkaido
Young shoots of giant knotweed, Polygonum sachalinense, carefully selected and harvested from wild stands
Step 2 · hot water
The shoots are extracted with hot water using a proprietary process
Step 3 · extract with dextrin
The extract is made into a powder; dextrin is declared on the label example, the ratio is not specified
Step 4 · 1 kg bag or 10 kg can
Aluminium bags of 1 kg or metal cans of 10 kg; made in Japan
Step 5 · 2 years unopened
Store in a cool, dark place, away from direct sunlight, high temperature and humidity
The grade on this page. Other grades, where available, are specified on request.
Example lot values are published in the developer's guide below. They are an example, not a specification; your lot's CoA governs.
A Japanese trading company selling directly to brand owners and contract manufacturers. No distributor layer between you and the documents.
Every shipment travels with the Certificate of Analysis of its own lot, with the measured values and the full safety panel.
A small first order lets you run a pilot batch before committing to bulk. Larger volumes are quoted by volume and delivery terms.
For registered companies developing a product. Tell us the format you plan and we will say honestly what to expect.
After payment is received. Freight quoted on request. Specification and SDS before you order, CoA with the goods.
If you are comparing ingredients for a new SKU, these questions separate one material from another quickly.
Rutin is the named marker, and quercetin and trans-resveratrol are named among the functional components, but no content figures are given. If your label, dossier or price comparison needs a number, ask for a lot analysis before you commit.
No. This is a hot-water extract of the young shoots of giant knotweed, a different species from Japanese knotweed, whose root is one of the richest natural sources of resveratrol. Compare specifications, not plant names.
Joint-related wording is regulated differently in the USA, the EU, the Gulf, Australia and the CIS. We hold no approved claim for this extract; set the wording with your regulatory adviser.
The young shoots have a food history in Japan, but a concentrated extract can be assessed separately from the plant. Check the status for your destination before the first order; for the EU we have not verified it.
No certificate is on file for this extract. In the UAE, supplements need a halal certificate. If your market or brand needs one, ask us before you order.
The documents on file are in Japanese and cover composition, packing, shelf life, storage and reference intake. Tell us at the inquiry stage which parameters your importer expects on the CoA, and whether you need an SDS, allergen or GMO statement.
What each component is, what the processing changes, and what published research on the raw material has examined. No health claims; references on request.
Giant Knotweed Shoot Extract Powder is a Japanese hot-water extract of the young shoots of wild giant knotweed, Polygonum sachalinense, harvested in Hokkaido and powdered with dextrin. The young shoots are a traditional spring vegetable in northern Japan. Iizuka Shoukai supplies the extract from Japan to brand owners and contract manufacturers.
The extract was developed in Japan for formulas in the joint-supplement category, and in its human study it was taken together with fermented glucosamine. At a reference intake of 240 mg per day it takes little room in a capsule or tablet, so it can sit next to glucosamine, chondroitin or collagen in one serving. For collagen, see our Fish Collagen Tripeptide and Fish Collagen Peptide.
The extract is suitable for granules, tablets, hard capsules, drinks and other food formats. One kilogram covers 4,166 daily servings at 240 mg. The label example declares dextrin together with the extract, so plan for dextrin on your ingredient list.
Tell us your format, target market and the other actives in the formula. If your label or dossier needs rutin, quercetin or resveratrol figures, or heavy metal and microbiology data, say so at the inquiry stage, before you commit to a trial. If you would rather receive a finished private-label product than the raw powder, see our Japanese supplement ingredients and contract manufacturing.
Giant knotweed is a large perennial of the buckwheat family (Polygonaceae). It appears in the literature as Polygonum sachalinense, Reynoutria sachalinensis or Fallopia sachalinensis, and in English also as Sakhalin knotweed. In Japan it grows in Hokkaido and in central and northern Honshu.
Its close relative is Japanese knotweed, Reynoutria japonica, also known as Polygonum cuspidatum. Of the two, only Japanese knotweed is accepted in pharmacopoeias as a herbal material (its rhizome and root), while giant knotweed has a history of folk use (Sci Rep 2025; 15: 6001). The names are easy to confuse, but these are different species with different chemistry.
Knotweed shoots have a long food history in Japan. Itadori is mentioned in classical texts such as the Nihon Shoki and The Pillow Book, and in the Tohoku region the young shoots of giant knotweed are still cooked today: stir-fried, dressed, seasoned with vinegar or added to salads. Ainu communities in Hokkaido are said to have eaten the young shoots raw. This extract is made from the young shoots, not from the root.
In knotweeds, the chemistry changes with the plant part. In wild Japanese and giant knotweed, the leaves were the better source of flavonols, phenolic acids and procyanidins, while the roots were the source of stilbenes such as resveratrol (Molecules 2019; 24(7): 1436). In plants from the Russian Far East, including the Sakhalin region, quercetin and its derivatives were the major compounds in the leaves and stems of both species (Plants 2024; 13(23): 3330).
For this extract the named marker is quercetin-3-rutinoside (rutin), with quercetin and trans-resveratrol also named among its functional components. No content figures are given, so if your label or dossier needs a number, ask for a lot analysis.
Rutin is quercetin bound to the sugar rutinose. Quercetin glycosides occur widely in plant foods; quercetin-3-rutinoside, for example, is the major flavonol in tea (J Nutr 2003; 133(6): 1806-1814).
The sugar decides how quercetin is taken up. When nine volunteers took quercetin glucoside or quercetin rutinoside, plasma quercetin peaked within half an hour after the glucoside but only after about six hours after the rutinoside, and the bioavailability of the rutinoside was about 20% of that of the glucoside. The authors concluded that the rutinoside is absorbed from the colon after its sugar is removed (Free Radic Res 1999; 31(6): 569-573). Colonic bacteria convert most of the ingested quercetin-3-rutinoside into smaller phenolic acids (J Nutr 2003; 133(6): 1806-1814). This is a question of uptake, not of effect.
Resveratrol is a stilbene, and Japanese knotweed rhizome is one of the richest natural sources of it (Molecules 2019; 24(6): 1136). Giant knotweed differs here: in a comparison of rhizomes, giant knotweed contained no detectable stilbenes, unlike Japanese knotweed (Planta Med 2018; 84(15): 1118-1126). This product is made from the shoots of giant knotweed and names trans-resveratrol among its components without a content figure. Do not compare it with resveratrol extracts of Japanese knotweed root; compare specifications.
The file on this extract includes an 8-week parallel-group study in Japanese adults aged 45 to 69 who reported knee discomfort. It compared a fermented glucosamine food with and without the extract, three tablets after each meal, using the JKOM knee questionnaire. The file also lists three studies in mice and two safety tests: a 28-day repeated-dose toxicity study and a micronucleus test, in which no changes attributable to the extract were observed. We make no claims from these data; the wording a finished product can carry is set by the rules of its market.
Plan it as a milligram-level ingredient: 240 mg per day gives 4,166 servings per kilogram. Declare dextrin together with the extract, and store the powder cool and dark, away from direct sunlight, high temperature and humidity.
Start at the minimum order. Free sample. Specification, SDS and lot CoA on request.
Request a sample or quotationGiant Knotweed Shoot Extract Powder is a Japanese hot-water extract of the young shoots of wild giant knotweed, Polygonum sachalinense, harvested in Hokkaido and powdered with dextrin. The young shoots are a traditional spring vegetable in northern Japan. Iizuka Shoukai supplies the extract from Japan to brand owners and contract manufacturers.
The extract was developed in Japan for formulas in the joint-supplement category, and in its human study it was taken together with fermented glucosamine. At a reference intake of 240 mg per day it takes little room in a capsule or tablet, so it can sit next to glucosamine, chondroitin or collagen in one serving. For collagen, see our Fish Collagen Tripeptide and Fish Collagen Peptide.
The extract is suitable for granules, tablets, hard capsules, drinks and other food formats. One kilogram covers 4,166 daily servings at 240 mg. The label example declares dextrin together with the extract, so plan for dextrin on your ingredient list.
Tell us your format, target market and the other actives in the formula. If your label or dossier needs rutin, quercetin or resveratrol figures, or heavy metal and microbiology data, say so at the inquiry stage, before you commit to a trial. If you would rather receive a finished private-label product than the raw powder, see our Japanese supplement ingredients and contract manufacturing.
Giant knotweed is a large perennial of the buckwheat family (Polygonaceae). It appears in the literature as Polygonum sachalinense, Reynoutria sachalinensis or Fallopia sachalinensis, and in English also as Sakhalin knotweed. In Japan it grows in Hokkaido and in central and northern Honshu.
Its close relative is Japanese knotweed, Reynoutria japonica, also known as Polygonum cuspidatum. Of the two, only Japanese knotweed is accepted in pharmacopoeias as a herbal material (its rhizome and root), while giant knotweed has a history of folk use (Sci Rep 2025; 15: 6001). The names are easy to confuse, but these are different species with different chemistry.
Knotweed shoots have a long food history in Japan. Itadori is mentioned in classical texts such as the Nihon Shoki and The Pillow Book, and in the Tohoku region the young shoots of giant knotweed are still cooked today: stir-fried, dressed, seasoned with vinegar or added to salads. Ainu communities in Hokkaido are said to have eaten the young shoots raw. This extract is made from the young shoots, not from the root.
In knotweeds, the chemistry changes with the plant part. In wild Japanese and giant knotweed, the leaves were the better source of flavonols, phenolic acids and procyanidins, while the roots were the source of stilbenes such as resveratrol (Molecules 2019; 24(7): 1436). In plants from the Russian Far East, including the Sakhalin region, quercetin and its derivatives were the major compounds in the leaves and stems of both species (Plants 2024; 13(23): 3330).
For this extract the named marker is quercetin-3-rutinoside (rutin), with quercetin and trans-resveratrol also named among its functional components. No content figures are given, so if your label or dossier needs a number, ask for a lot analysis.
Rutin is quercetin bound to the sugar rutinose. Quercetin glycosides occur widely in plant foods; quercetin-3-rutinoside, for example, is the major flavonol in tea (J Nutr 2003; 133(6): 1806-1814).
The sugar decides how quercetin is taken up. When nine volunteers took quercetin glucoside or quercetin rutinoside, plasma quercetin peaked within half an hour after the glucoside but only after about six hours after the rutinoside, and the bioavailability of the rutinoside was about 20% of that of the glucoside. The authors concluded that the rutinoside is absorbed from the colon after its sugar is removed (Free Radic Res 1999; 31(6): 569-573). Colonic bacteria convert most of the ingested quercetin-3-rutinoside into smaller phenolic acids (J Nutr 2003; 133(6): 1806-1814). This is a question of uptake, not of effect.
Resveratrol is a stilbene, and Japanese knotweed rhizome is one of the richest natural sources of it (Molecules 2019; 24(6): 1136). Giant knotweed differs here: in a comparison of rhizomes, giant knotweed contained no detectable stilbenes, unlike Japanese knotweed (Planta Med 2018; 84(15): 1118-1126). This product is made from the shoots of giant knotweed and names trans-resveratrol among its components without a content figure. Do not compare it with resveratrol extracts of Japanese knotweed root; compare specifications.
The file on this extract includes an 8-week parallel-group study in Japanese adults aged 45 to 69 who reported knee discomfort. It compared a fermented glucosamine food with and without the extract, three tablets after each meal, using the JKOM knee questionnaire. The file also lists three studies in mice and two safety tests: a 28-day repeated-dose toxicity study and a micronucleus test, in which no changes attributable to the extract were observed. We make no claims from these data; the wording a finished product can carry is set by the rules of its market.
Plan it as a milligram-level ingredient: 240 mg per day gives 4,166 servings per kilogram. Declare dextrin together with the extract, and store the powder cool and dark, away from direct sunlight, high temperature and humidity.
No. Giant knotweed (Polygonum sachalinense) and Japanese knotweed (Polygonum cuspidatum) are related but different species. The root of Japanese knotweed is one of the richest natural sources of resveratrol. This product is a hot-water extract of the young shoots of wild giant knotweed from Hokkaido; its named marker is quercetin-3-rutinoside (rutin), and no resveratrol content is specified.
Iizuka Shoukai supplies Giant Knotweed Shoot Extract Powder from a 1 kg minimum order, packed in 1 kg aluminium bags, with 10 kg cans also available, and sends the price for your volume with the quotation. Larger orders are quoted by volume and freight is quoted on request. Material ships from Japan 1-1.5 weeks after payment when stock is available; otherwise timing is confirmed in your quotation. Payment is 100% prepayment by SWIFT or Stripe. A free 20 g evaluation sample is available for registered companies developing a product.
The reference intake is 240 mg per day, so one kilogram covers 4,166 daily servings. At that level the extract fits into one capsule or tablet next to other actives. It is suitable for granules, tablets, hard capsules, drinks and other food formats. The label example declares dextrin together with the extract.
That depends on your market, not on the ingredient. The file on this extract includes an 8-week study in adults that used a knee questionnaire, three mouse studies and two safety tests, but we hold no approved claim for this extract and do not make one. Joint-related wording is regulated differently in the USA, the EU, the Gulf, Australia and the CIS; set it with your regulatory adviser.
