Continuous Glucose Monitor Buyer's Guide 2026: The Numbers Nobody Explains Before You Buy
Every continuous glucose monitor on the market claims to be accurate, small, and easy to use. That marketing language is not wrong, but it is not the whole story either, and it rarely helps you pick between devices. This guide breaks down the one metric that actually separates them, walks through what needs a prescription versus what does not, and lays out real numbers from head to head research rather than manufacturer talking points. The Accuracy Number Nobody Explains Well Every cgm device is graded on MARD, or mean absolute relative difference, which measures how far sensor readings drift from an actual lab blood draw. Lower is better. Most modern sensors sit in the high single digits, which clinicians consider reliable enough for treatment decisions, but a 2026 head to head study of 55 adults found a real gap that manufacturer brochures do not advertise. Prescription CGMs vs Over the Counter Options Not every glucose monitor on shelves today needs a doctor's note anymore....