The Best Glucose Monitors

Two very different people read this article, and the honest advice for them is opposite.

If you take insulin or a sulfonylurea, this is safety equipment. A GLP-1’s own effect on insulin release is glucose-dependent, so it rarely causes lows alone — but those two drug classes are not glucose-dependent, and adding a medicine that cuts intake by 30–50% on top of them is the standard route to a hypo, and the treatment threshold is 70 mg/dL. The full picture is in hypoglycemia on a GLP-1.

If you have no diabetes and are taking a GLP-1 for weight, routine glucose monitoring is not standard practice and mostly will not change what you do. I will come back to that.

The rubric

1. Accuracy, judged against independent testing rather than marketing.
2. Trend and direction, which is what prevents a low rather than documenting one.
3. Alarms, configurable and audible.
4. Wear time and reliability, for sensors.
5. Total cost of ownership — strips and sensors, not the device.
6. Integration with pumps, phones and watches.
7. Availability and insurance coverage.

The ranking

1. Dexcom G7

Best overall if you take insulin.

Continuous monitoring with configurable alerts including predictive low alarms, a warm-up measured in 30 minutes rather than hours, and broad integration with pumps and phones. The clinical value of a CGM over finger-sticks is not the individual number — it is direction and rate of change, which is what lets you act before a low rather than after.

Where it falls short. Expensive without coverage. Sensor adhesion fails for some people, particularly in heat. Compression lows overnight — pressure on the sensor while sleeping — generate false alarms that wake you.

2. Abbott FreeStyle Libre 3

Closest competitor, often cheaper and more available.

Small sensor, long wear time, real-time readings with alarms, and generally wider availability and lower cost than Dexcom in many markets. Current-generation accuracy is comparable, and the practical differences matter more than the specification differences.

Where it falls short. Fewer integrations with insulin pumps than Dexcom. Reader and phone compatibility is narrower. Adhesion issues affect some users similarly.

3. Contour Next One

Best finger-stick meter on accuracy.

Independent accuracy testing has consistently placed the Contour Next platform at the top of the meter field, and if a reading is going to inform an insulin dose, that is the criterion that matters. Bluetooth, second-chance sampling so you can re-apply blood without wasting a strip, and a simple interface.

Where it falls short. A meter shows a point in time and no direction, which is the fundamental limitation against a CGM. Strip cost is the real long-term expense.

4. Accu-Chek Guide

Best strip handling and value.

Reliable accuracy, a spill-resistant strip vial that lets you take a strip one-handed, good app, and competitive strip pricing. A very sensible default meter.

Where it falls short. Same point-in-time limitation. Slightly behind Contour in independent accuracy comparisons.

5. OneTouch Verio Reflect

Best guidance for someone new to monitoring.

Colour-coded range indicators and on-screen coaching, which genuinely helps people who have never monitored before make sense of a number rather than just recording it. Widely available, strips easy to obtain.

Where it falls short. The guidance features are of little use to experienced users. Strip cost is at the higher end.

6. Dexcom Stelo

Best over-the-counter option for people without insulin.

A CGM available without prescription, aimed at people with type 2 diabetes not on insulin and at those simply wanting visibility. It is the sensible way to satisfy curiosity about your own glucose responses without a prescription.

Where it falls short. No low-glucose alarms in the way the prescription systems have them, which makes it unsuitable as safety equipment for anyone on insulin or a sulfonylurea. Subscription cost adds up quickly for data that rarely changes a decision.

7. Basic supermarket meters, as a category

Cheapest, and buy on strips rather than device.

Inexpensive meters meeting the regulatory minimum are widely sold, and for occasional checking in someone at low risk they are adequate.

Where they fall short. Independent testing has repeatedly found meaningful accuracy variation among meters that all meet the standard. If a reading informs an insulin dose, that variation is not academic. Also check strip price and long-term availability before buying — a cheap meter with expensive or discontinued strips is a false economy.

Summary

The honest section on CGM without diabetes

They are compelling. You see a graph, you learn that white bread does more than oats, and it feels like insight.

Two things worth weighing. Readings within non-diabetic ranges are noisier than the smoothed graphs suggest, and small differences get over-interpreted. And in someone without diabetes, almost nothing a CGM shows changes what they should do — the advice was already protein-forward meals, resistance training, and adequate sleep.

If you are curious, a single 2 week sensor as a one-off is a reasonable experiment. An indefinite subscription mostly buys anxiety about numbers that were never abnormal, and the money is better spent on the things in what to actually eat and the training rankings.

If you do take insulin or a sulfonylurea

Beyond the device:

• 15 g of fast carbohydrate in the house, the car and your bag — not chocolate
• Glucagon prescribed, and someone at home who knows where it is — review it every 12 months for expiry
• Check before driving, keep glucose in the vehicle, and wait 45 minutes after treating a low
• Dose reductions planned at the start and at every 4 week escalation, not discovered
• A sick-day plan — sick day rules

The equipment is the easy part. The dose adjustments are what actually prevent the problem.