Ingredient Science

Quercetin Benefits and Immune Support

By Tonic Greens Research Team · Reviewed by Dr. Emily Hart, M.D. · Updated June 2026

Quercetin is one of the most researched plant flavonoids for immune and antioxidant support — and a featured ingredient in TonicGreens. Here's why it matters.

What Is Quercetin?

Quercetin is a flavonoid found in foods like onions, apples, and berries, traditionally used to support antioxidant status (PubMed).

Supports a Healthy Immune Response

Quercetin is traditionally used to support the body's natural immune defenses.

Provides Antioxidant Support

As an antioxidant, Quercetin helps the body combat free radicals as part of a healthy lifestyle.

Quercetin in Tonic Greens

In Tonic Greens, Quercetin joins Spirulina, Reishi, and dozens of other superfoods — see the ingredients page and the current Tonic Greens discount on the Tonic Greens official website.

Quercetin supports antioxidant and immune health and is not a treatment for any illness. Consult your doctor before use if you take medication.

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