Cross-referencing clinical data
A pairing appears on this page only when a trial gave both ingredients together and measured the result. Cranesbill 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.
Tannins form insoluble complexes with ferric iron before it reaches the absorptive surface, which is the same mechanism by which strong tea lowers iron uptake from a meal. Cranesbill root delivers a concentrated tannin dose, so the effect is larger than from a beverage. Anyone supplementing iron for low iron status should separate the two by at least two hours. This is a genuine interaction, not a theoretical one.
Where a tannin-rich preparation and iron cannot be separated in time, ascorbate partially rescues uptake by reducing ferric iron to the ferrous form carried by DMT1 and by competing for the iron that tannins would otherwise bind. The rescue is partial, not complete. Separating the doses remains the more reliable approach.
Tannins complex readily with dietary protein, and a protein load taken at the same time will occupy much of the tannin present. That cuts both ways: the protein blunts the astringency and mucosal binding that cranesbill is used for, and the tannin can reduce the digestibility of that protein fraction. If cranesbill is being used for its local astringent action, protein at the same sitting works against it.
Herbal practice combines an astringent with a demulcent so that the tightening action is buffered by a soothing film. Cranesbill supplies the astringency and marshmallow the polysaccharide coat. The logic is physical and traditional rather than tested in controlled trials. No human data compares the pair to either component.
Cranesbill is a North American native and its traditional use sits alongside slippery elm in the same eclectic formulas. Slippery elm mucilage provides the coating layer, cranesbill the astringent one. Both are surface-acting agents in the lumen with essentially no systemic absorption of the active fraction. Read the pairing as tradition, not evidence.
Zinc absorption is sensitive to chelating dietary components, and tannins are among them. The interaction is less well quantified for zinc than for iron but rests on the same chemistry. Spacing a zinc dose away from a tannin-heavy herbal preparation removes the concern at no cost.
Tannins inhibit digestive proteases and amylases in vitro by binding the enzyme protein itself. Taking a supplemental enzyme blend in the same swallow as a concentrated tannin preparation puts the two in contact at the highest concentration either will reach. Separating them by an hour avoids the overlap entirely.
Tannin fractions show growth inhibition against several bacterial genera in culture, and the same chemistry does not distinguish between organisms a person wants and organisms they do not. Whether this measurably affects a live probiotic dose in the gut has not been established in people. Spacing the two is a reasonable precaution rather than a demonstrated need.
Nothing specific on file for Cranesbill. 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.