Cross-referencing clinical data
A pairing appears on this page only when a trial gave both ingredients together and measured the result. Pacific Madrone 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.
Madrone bark and leaf are tannin rich, and condensed tannins bind non heme iron in the gut lumen into complexes that are poorly taken up. Anyone using a bark decoction alongside an iron supplement is losing part of the iron dose. Separating them by a couple of hours resolves it. Heme iron from meat is much less affected.
Arbutus menziesii sits in the same family as Arctostaphylos uva ursi and shares the hydroquinone glycoside arbutin along with a heavy tannin load. Using both means adding the same constituents rather than different ones. Hydroquinone exposure is the reason traditional guidance limits duration of use for arbutin bearing plants. Count them together, not separately.
Arbutin is absorbed and excreted largely as hydroquinone conjugates, and the traditional urinary use of arbutin bearing plants assumes alkaline urine for the free hydroquinone to be released. Alkalinising agents shift urine pH in that direction and acidifying inputs shift it back. This is why old herbal texts pair these plants with alkaline diets. The clinical relevance in modern practice is debated and the chemistry is not.
High dose ascorbate lowers urinary pH, which sits against the alkaline condition traditionally paired with arbutin bearing plants. In the gut, though, ascorbate partly offsets tannin binding of non heme iron, so the same pairing helps in one place and hinders in another. Which matters depends on why the plant is being used. Both directions come from established chemistry rather than from trials on this species.
Tannins bind calcium alongside other minerals, lowering the fraction absorbed from a dose taken at the same time. The effect is smaller than for iron because calcium doses are typically much larger. Spacing a strong bark preparation away from a mineral supplement is a reasonable habit. Dietary calcium in a mixed meal is less affected.
Nothing specific on file for Pacific Madrone. 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.