Cross-referencing clinical data
An ancient Chinese antiviral herb (Ban Lan Gen) used for centuries against infections and fevers. Indirubin and indigo alkaloids inhibit viral replication. Epigoitrin shows antiviral activity against influenza. Root polysaccharides stimulate innate immune response.
Reviewed March 2026
These words describe the research, not the molecule's worth. Research strength is how much work stands behind one claim, and it is never a product score.
A pairing appears on this page only when a trial gave both ingredients together and measured the result. Woad 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.
Isatis root is rarely used alone in the tradition it comes from; licorice is one of the herbs it is customarily combined with, partly as a taste and harmonising agent. That is a documented use pattern rather than a measured interaction. Licorice carries its own sodium and potassium handling effects that belong in any assessment of the pair.
Astragalus and Isatis root appear together in traditional multi-herb preparations aimed at seasonal use. The pairing rests on traditional formulation logic, with no combination pharmacology to cite. Nothing here establishes an additive biological effect.
Glucosinolates only become active after myrosinase from the plant or from gut bacteria cleaves them, which is the same activation step behind sulforaphane. A Brassicaceae extract such as woad therefore shares an activation dependency rather than an effect. Whether any given woad preparation retains active myrosinase depends on how it was dried and processed.
Woad root extract shows up in seasonal-use blends alongside vitamin C because of how those products are put together, not because of a shared pathway. Vitamin C has its own established role in normal immune function. No combination data exist for the pair.
Zinc is a standard component of seasonal blends that also carry botanical extracts such as Isatis root. The zinc contribution is well characterised on its own; the botanical contribution is not. Nothing about the pairing has been tested together.
Elderberry and Isatis root are used in the same product category and sometimes in the same product. The two carry entirely different phytochemistry, anthocyanins on one side and indole alkaloids and glucosinolates on the other. Co-occurrence in formulas is the whole basis, so the confidence is low by design.
Talk to a doctor before taking Woad if any of these apply to you: Limited Western clinical evidence, May cause nausea or diarrhea at high doses, Not a substitute for antiviral medications. These are flags to check first, not effects Woad is known to cause.
Not medical advice. Show the label to your pharmacist.The whole-food sources on file. A supplement closes the gap, it does not replace dinner.
A gram-for-gram figure (how much of each you would eat to match a dose) will appear here once it is sourced and reviewed. This page will not print a number it cannot cite.
These are the studies our verdict leans on, chosen from the 157 we read for Woad. The full linked list is below.
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.