How to Choose a CGM

There is no single "best" continuous glucose monitor — the right choice depends on your needs, your clinician's advice, and what's available where you live. This guide lays out the factors worth weighing so you can have a more informed conversation, without steering you toward any particular product. Specifications and availability change frequently, so treat everything here as a framework to confirm rather than a fixed answer.

Prescription vs. over-the-counter

The first fork is whether a device requires a prescription. Many CGMs, especially those designed for diabetes management, are obtained through a clinician. In some regions, over-the-counter sensors aimed at general wellness have started to appear, which changes the access route but also the intended use. If you don't have diabetes, our page on CGM for people without diabetes is worth reading first, since it addresses what these sensors can and can't tell you. Either way, requirements differ by country and evolve over time, so verify the current situation locally.

Wear time and calibration

Sensors differ in how long each one lasts before replacement, which affects both convenience and running cost. They also differ in calibration: some are factory-calibrated and need no finger-prick checks, while others may require occasional calibration. If you want to understand why calibration exists at all, CGM accuracy explains how sensors are validated, and CGM vs. fingerstick covers how the two measurement methods relate. Neither approach is universally superior; they're trade-offs to match to your preferences.

Real-time vs. scanning

CGMs broadly fall into two interaction styles. Real-time devices stream readings continuously to a receiver or phone and can push alerts without you doing anything. Scanning (sometimes called intermittently scanned) devices require you to pass a reader or phone over the sensor to retrieve stored data. The distinction shapes daily use: real-time suits people who want passive alerts, while scanning may appeal to those who prefer to check on their own schedule. How the underlying sensor produces those readings is covered in how CGM works.

Alerts

Alert capability varies. Real-time systems can warn about highs, lows, or rapid changes, which some people find valuable and others find intrusive. Consider whether customizable thresholds matter to you, whether alerts can be silenced at night, and whether the alerting features are appropriate for your situation — a question a clinician can help answer.

Phone compatibility and apps

Because most modern CGMs pair with a smartphone, compatibility is a practical gatekeeper. Check that your specific phone model and operating-system version are supported, since compatibility lists change with each release. The companion app also shapes your experience: how it displays data, whether it produces a standard report like the Ambulatory Glucose Profile, and whether it can share data with a clinician. If reviewing that data is the goal, our guide to reading CGM data may help you get more from whichever app you use.

Cost and coverage

Cost is often the deciding factor, and it varies widely by product, region, and whether the device is covered by insurance or a health plan. Coverage rules and out-of-pocket prices change over time, so the only reliable approach is to confirm current details with your insurer, the manufacturer, and your clinician. Ongoing sensor replacement cost, not just the upfront price, is worth factoring in.

Putting it together

A sensible way to decide is to rank which of these factors matter most to you — passive alerts, minimal calibration, low cost, a particular app — and then compare current, verified specifications against that ranking. Because the market moves quickly, resist relying on older comparisons. Above all, discuss the choice with a qualified clinician, who can weigh your health context, and confirm the specifics with the manufacturer's current documentation. Endobits does not endorse or sell any sensor; it is clinical decision-support software that helps clinicians interpret CGM data under their oversight, whatever device produced it.

Sources

American Diabetes Association, diabetes.org, on continuous glucose monitoring devices and their use. National Institute of Diabetes and Digestive and Kidney Diseases, niddk.nih.gov, on continuous glucose monitoring. Centers for Disease Control and Prevention, cdc.gov/diabetes, on monitoring blood glucose.

Related: The complete CGM guide · CGM sensors compared · CGM vs. fingerstick · CGM without diabetes