Best Quercetin Form: Which One Is Right for You?

Quercetin is a flavonoid antioxidant found in onions, apples, and berries, researched for immune support and vascular health. Like many polyphenols, its bioavailability from unformulated sources is modest — absorption varies significantly by the chemical form, glycosylation state, and whether the product uses a delivery technology to improve solubilization. This guide covers the commercially relevant forms ranked by pharmacokinetic evidence.

Updated 2026 · Reviewed by Dr. Brennan Commerford, D.C.

All Forms Ranked by Evidence

1. 1

   100/ 100· Top TierBest by Evidence

   EubioQuercetin®

2. 2

   75/ 100· Strong

   Quercetin (Sophora japonica)

   Form: Sophora japonica

3. —

   Verification pending

   Alpha-Glycosyl Isoquercitrin

   Form: Standard

   Alpha-Glycosyl Isoquercitrin — Alpha-Glycosyl Isoquercitrin is one form of this compound. Limited direct human-PK evidence for this specific form. We grade forms only where form-specific human pharmacokinetic evidence exists; this form does not yet meet that bar, so we do not assign it a benefit rating.

4. —

   Verification pending

   Japanese Sophora japonica Flower Bud Extract

   Form: Standard

   Japanese Sophora japonica Flower Bud Extract — Japanese Sophora japonica Flower Bud Extract is one form of this compound. Limited direct human-PK evidence for this specific form. We grade forms only where form-specific human pharmacokinetic evidence exists; this form does not yet meet that bar, so we do not assign it a benefit rating.

5. —

   100/ 100· Top Tier

   Quercefit (Quercetin Phytosome)

   Form: Quercetin Phytosome

   Quercefit (Quercetin Phytosome) — Quercefit (Quercetin Phytosome) is one form of this compound. The rating above reflects its absorption chemistry only. Limited direct human-PK evidence for this specific form. We grade forms only where form-specific human pharmacokinetic evidence exists; this form does not yet meet that bar, so we do not assign it a benefit rating.

6. —

   95/ 100· Top Tier

   Quercetin Dihydrate

   Form: Dihydrate

   Quercetin Dihydrate — Quercetin Dihydrate is one form of this compound. The rating above reflects its absorption chemistry only. Limited direct human-PK evidence for this specific form. We grade forms only where form-specific human pharmacokinetic evidence exists; this form does not yet meet that bar, so we do not assign it a benefit rating.

7. —

   75/ 100· Strong

   Rutin

   Form: Standard

   Rutin — Rutin is one form of this compound. The rating above reflects its absorption chemistry only. Limited direct human-PK evidence for this specific form. We grade forms only where form-specific human pharmacokinetic evidence exists; this form does not yet meet that bar, so we do not assign it a benefit rating.

8. —

   Verification pending

   Sophora japonica (Flower) Extract

   Form: 95% Quercetin

   Sophora japonica (Flower) Extract — Sophora japonica (Flower) Extract is one form of this compound. Limited direct human-PK evidence for this specific form. We grade forms only where form-specific human pharmacokinetic evidence exists; this form does not yet meet that bar, so we do not assign it a benefit rating.

9. —

   95/ 100· Top TierFF Preferred

   SunActive®-IsoQ (Isoquercitrin)

   Form: SunActive®

   SunActive®-IsoQ (Isoquercitrin) — SunActive®-IsoQ (Isoquercitrin) is one form of this compound. The rating above reflects its absorption chemistry only. Limited direct human-PK evidence for this specific form. We grade forms only where form-specific human pharmacokinetic evidence exists; this form does not yet meet that bar, so we do not assign it a benefit rating.