Quercetin

Of 2,238 on-market quercetin products in the January 2026 DSLD dump, the median declared dose is 100 mg, and 99.0% list Quercetin Dihydrate as the primary form.

2,238

on-market products

100 mg

median dose

—

below RDA

—

above UL

Form share

Of 2,214 products with an identifiable primary form, here is the share held by each form of Quercetin on the market today.

Form	Quality tier	n	Share
Quercetin Dihydrate	Tier 2	2,191	99.0%
Sophora japonica / Dimorphandra mollis extract (source-plant labeling)	Unrated	23	1.0%

Form share over time

Entry-year breakdown of the top forms, 2012–2025.

Dose distribution

Deciles of declared dose per serving (mg), among 1,505 products with a disclosed amount.

13.2% of products fall below the fairy-dust threshold (20 mg, 20% of the studied low dose).
31.4% of products don't disclose an amount because Quercetin is declared inside a proprietary blend.

By dosage form

By target group

Top brands

Brand	Products
Source Naturals	72
Pure Encapsulations	36
Life Extension	35
DC	34
Purity Products	33
Emergen-C	31
Wonder Laboratories	29
Douglas Laboratories	28
XYMOGEN	27
Bluebonnet	26
Ortho Molecular Products	23
Metagenics	22
The Vitamin Shoppe	21
Designs for Health	21
Pure Essence	21
NutriCology	20
Terra Origin	20
Allergy Research Group	18
FRS	17
Bluebonnet Super Earth	17
Nutri-West	16
Perque	16
GNC SuperFoods	16
ProEnzol	16
Herbadiet	16

Forms explained

Quercetin Dihydrate Tier 2

Standard crystalline form used in most human RCTs including the BP meta-analysis, but has documented poor intrinsic solubility/absorption (<5% oral bioavailability in bioavailability reviews).

Source: Serban MC et al. 2016, J Am Heart Assoc 5(7):e002713, PMID 27405810

Quercetin Phytosome (lecithin-complexed) Tier 1

Directly compared head-to-head against standard quercetin in human PK trials and shown to substantially increase plasma exposure (~20-fold higher in one 12-subject crossover) at equal or lower dose.

Source: Riva A et al. 2019, Eur J Drug Metab Pharmacokinet 44(2):169-177, PMID 30328058

Sophora japonica / Dimorphandra mollis extract (source-plant labeling) Unrated

Raw-material source descriptors, not a functionally distinct delivery form -- insufficient evidence they differ from generic quercetin dihydrate/aglycone once standardized.

Source: uncertain -- needs review

Reference values

RDA (adult): not established — Plant-derived flavonoid, not an essential nutrient; no DRI exists.
Tolerable Upper Intake Level (adult): not established — Not established -- no IOM/NASEM UL exists. Trials up to ~1000mg/day for weeks have not reported serious adverse effects, but this is not a formal UL.
Studied clinical dose range: 100–1000 mg
Serban MC et al. 2016, J Am Heart Assoc 5(7):e002713, PMID 27405810 -- meta-analysis, pooled RCTs (100-1000mg/day); significant blood-pressure reduction, significant only at doses >=500mg/day.