flavonoid quercetin

Most quercetin supplements are sold as capsules (including vegetarian/vegetable capsules). Many listings also carry dietary labels such as vegan, vegetarian‑friendly, non‑GMO, and gluten‑free.

Products positioned for immune or respiratory support commonly combine quercetin with vitamin C (including Ester‑C), bromelain, rutin, and botanicals such as stinging nettle. Some listings also emphasize bromelain to aid absorption.

Listings describe several approaches: pairing quercetin with bromelain, combining it with Ester‑C (vitamin C) to support absorption/retention, and using phytosome or lecithin‑based complexes (standardized phytosome formats) in some formulas.

Most product entries show capsule counts such as 60 or 90, though some use other counts. Some listings also state servings (for example, a 60‑capsule bottle shown as 30 servings at two capsules per serving), while others list only the capsule quantity without a servings breakdown.