Cross-referencing clinical data
A pairing appears on this page only when a trial gave both ingredients together and measured the result. Pacific willow 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.
Both are Salix barks carrying salicin and related phenolic glycosides, so combining them stacks the same precursor pool rather than adding anything new. Salicin content swings widely by species, bark age and harvest season, which makes the combined intake hard to know. Anyone using both is doubling one input, not broadening it.
Salicin is converted in the body to salicylic acid, which dampens cyclooxygenase activity and lowers thromboxane generation. High intakes of EPA-rich oil shift eicosanoid balance in the same direction. The two point the same way, so the relevant point is additive bleeding tendency rather than any benefit. This is a flag, not a pairing suggestion.
Gingerols reduce thromboxane synthesis in platelet preparations, and willow-derived salicylate acts on the same arm of eicosanoid signalling. Human data on the combination are absent, so this is mechanistic reasoning carried over from single-agent work. It is listed so the direction of the interaction is visible.
Nattokinase acts on fibrin, while salicylate metabolites act on platelets. Different steps, same net direction, so the combination is worth flagging rather than pairing. No human study has examined the two together, and the reasoning here is mechanistic only.
Willow bark preparations are often sold alongside ascorbate, mostly as an antioxidant stabiliser for the polyphenol fraction during storage. There is no evidence that ascorbate changes salicin absorption or conversion in people. Regard the pairing as formulation convention rather than a pharmacological one.
Salicin is a glucoside and needs beta-glucosidase activity, much of it from gut bacteria, before the aglycone can be absorbed and oxidised to salicylic acid. Someone with a heavily disrupted microbiota may convert less of the dose. Whether a specific probiotic strain raises that conversion has not been shown in people, so this is mechanism rather than a measured effect.
Nothing specific on file for Pacific willow. Match the label to the daily amount above, and tell your doctor what you take.
Not medical advice. Show the label to your pharmacist.These are the studies our verdict leans on, chosen from the 1 we read for Pacific willow. The full linked list is below.
1 source behind our Pacific willow verdict: peer-reviewed studies and registered clinical trials. Every one links straight to PubMed, the journal, or ClinicalTrials.gov. Read them yourself.
Evidence surfaced via Semantic Scholar (Allen Institute for AI) and ClinicalTrials.gov. Ranked by study type and citation weight, not cherry-picked.
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.