Winter is a stress test for your immune system, not a season for trial and error. Trade scattershot remedies for a steady routine that feeds your microbiome, protects your airways, and respects your sleep. Use this checklist to be ready before the first sniffle. Table of Contents: Microbiome First: Food as Immune Signal Vitamin C : Does it really help? Nasal Defence That Works: Hypertonic Saline Air Matters: Humidity & Sleep Smart Extras: Earned, Not Automatic Clinician Quick