Cross-referencing clinical data
A pairing appears on this page only when a trial gave both ingredients together and measured the result. German Knotweed has none that clears that bar.
Stitching two separate single-ingredient studies into a pairing is the one thing this engine will not do. When a study of the combination itself holds up at source, it lands here with its citation.
No invented synergy. Where actives were studied on their own rather than together, the record shows each on its own evidence, never a combined effect no trial measured.
Research strength. Research strength says how much work stands behind the combination. It is never a product score.
Independent record. Every finding is cited to a named trial, dated, and never written by the brand.
20 pairings are live across the library today. Checked 20 July 2026.
No study gave these as a pair, so they are not in the card above. But the reason they belong together is settled biochemistry, not a guess, so it is worth knowing.
Most resveratrol on the supplement market is extracted from knotweed root rather than from grapes, because the root concentration is far higher. Piceid, the glucoside form, has to be deglycosylated before the aglycone is absorbed. Anyone stacking a knotweed extract with a resveratrol isolate is largely doubling the same molecule.
Pterostilbene resists phase II conjugation better than resveratrol does, so it survives first pass more completely. The two hit overlapping targets, meaning the combination is not additive in the way two unrelated ingredients would be. Stacking is common practice with little human comparison behind it.
Quercetin competes for the conjugating enzymes that clear stilbenes rapidly, which is the standard rationale for pairing them. The competition is documented in enzyme and cell systems. Whether it produces a meaningful change in circulating stilbene levels in people is not settled.
Knotgrass and its relatives carry appreciable condensed and hydrolysable tannins, which form insoluble complexes with dietary and supplemental iron. Taking a knotweed preparation alongside iron works against the iron. Separating them across the day is the practical answer.
Ascorbate keeps iron in the ferrous form and competes with tannins for it, blunting but not removing the inhibition. It also slows the browning of polyphenol extracts during storage. This is class chemistry, applicable to any tannin-rich botanical.
Silymarin and stilbenes are both heavily glucuronidated on first pass, so co-dosing means competition for the same limited enzyme capacity. That can nudge exposure of either one up. It is a pharmacokinetic observation from the class rather than a tested pairing.
Nothing specific on file for German Knotweed. Match the label to the daily amount above, and tell your doctor what you take.
Not medical advice. Show the label to your pharmacist.FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.