Self-Care for Common Colds: The Pivotal Role of Vitamin D, Vitamin C, Zinc, and Echinacea in Three Main Immune Interactive Clusters (Physical Barriers, Innate and Adaptive Immunity) Involved during an Episode of Common Colds—Practical Advice on Dosages and on the Time to Take These Nutrients/Botanicals in order to Prevent or Treat Common Colds

This 2018 narrative review by Rondanelli et al., published in Evidence-Based Complementary and Alternative Medicine, synthesizes findings from 82 studies to evaluate the roles of vitamin D, vitamin C, zinc, and Echinacea in supporting immune function across three key domains: physical barriers, innate immunity, and adaptive immunity. The authors report