Cistus incanus

Tier 3 — weak evidence · Immunity · Antiviral · Biofilm

A Mediterranean shrub traditionally used as tea for immune support. Lab studies show strong antiviral activity and the ability to disrupt bacterial biofilms. One small German trial found it reduced cold symptoms, but the study was industry-funded and has not been replicated. More human research is needed before it can be recommended with confidence.

Dose: 500–1,500 mg/day extract or 2–3 cups cistus tea; very limited human trial data