Quercetin Dihydrate
Also known as: quercetin, quercetin hydrate, 3,3',4',5,7-pentahydroxyflavone, Sophora japonica extract
Quercetin dihydrate is the standard crystalline form of the flavonol quercetin, typically extracted from Sophora japonica flower buds and supplied at 95% or higher purity. It is one of the most common flavonoids in immune, seasonal-comfort, and antioxidant formulas and is often combined with bromelain, vitamin C, or zinc. Plain quercetin is poorly soluble in water, and only a small fraction of an oral dose is absorbed, which is why phospholipid and other enhanced forms exist.
Research summary
Studied for mast-cell stabilizing, antioxidant, and senolytic activity in preclinical and small human studies.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 500 mg | 500–1,000 mg | — | — |
Absorption is limited; taking it with a meal containing fat improves uptake. Doses are often split into two servings. Note that comparisons across studies are complicated by the low and variable bioavailability of the plain dihydrate.
Standardization: ≥95% quercetin (as dihydrate)
Source material: Sophora japonica bud extract
Forms of Quercetin
| Form | Typical dose | Element % | Formats | Price |
|---|---|---|---|---|
| Quercetin Dihydrate | 500–1,000 mg | — | Capsule, Powder, Tablet | mid |
| Quercetin Phytosome (Quercefit) | 250–500 mg | — | Capsule, Powder, Tablet | premium |
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Bright yellow, bitter, and hydrophobic; stains and is difficult in gummies.
Formulation notes
Commonly paired with bromelain and vitamin C. Yellow pigment can discolor light-colored powders.
Sources
Related ingredients
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