Research
Micronutrients & recovery
Quercetin glucosides from onions have higher bioavailability and absorption rates than quercetin aglycones or rutinosides (from tea/apples) due to active transport mechanisms.
If you are seeking quercetin for health benefits, onions may be a more efficient source than tea or apples because your body absorbs the quercetin from onions better. The chemical form attached to sugar in onions allows for active absorption.
GoodSupportsHIGH confidence
This suggested that quercetin glucoside from onions has the highest extent of intestinal absorption relative to quercetin rutinoside and aglycone. This can be explained by the different routes of absorption across the intestinal wall. Quercetin glucosides are absorbed by SGLT 1 which is an active transporter that requires energy for its action and thus has a higher absorption rate than the passive transport of the aglycones across the intestinal wall.
Why this rating
Supported by multiple human studies comparing urinary excretion and plasma concentrations of different forms.
Source
Dietary Quercetin and Kaempferol: Bioavailability and Potential Cardiovascular-Related Bioactivity in Humans
Wijdan M. Dabeek et al. · Nutrients · 2019
DOI 10.3390/nu11102288
narrative_reviewCited 798×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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