Quercetin

Tier 3 — weak evidence · Anti-inflammatory · Antiviral · Longevity

A plant compound with impressive antioxidant and antiviral activity in lab studies, but poor real-world results. NCCIH notes that only about 1% is absorbed in its basic form, so the impressive lab results don't reliably translate to actual benefits. The phytosome form absorbs better. Human trial evidence remains weak and inconsistent overall.

Dose: 500–1,000 mg/day quercetin phytosome for improved absorption; evidence base insufficient