Cross-referencing clinical data
A pairing appears on this page only when a trial gave both ingredients together and measured the result. Pacific Yew 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.
Taxane diterpenes from yew are cleared through CYP3A4 and CYP2C8. Piperine inhibits CYP3A4 and intestinal efflux, which raises exposure to substrates of that enzyme. With a compound class this narrow in margin, raised exposure is a hazard rather than a benefit. This row exists as a warning, not a pairing.
Hypericum induces CYP3A4 strongly and lowers plasma levels of taxane-class drugs, an interaction documented in oncology pharmacology. The direction is loss of exposure. Anyone on a taxane medicine has a clinically meaningful reason to avoid this combination and should raise it with their prescriber.
Silymarin inhibits UGT and, at higher concentrations, CYP3A4 in laboratory systems, both of which handle taxanes. Human pharmacokinetic work on the combination is limited and inconsistent. The plausible direction is altered taxane clearance, which is why it belongs on a caution list rather than a stack.
Nothing specific on file for Pacific Yew. 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.