The best CGM for type 2 diabetes depends on whether you use insulin, how much you want to spend, and whether you need real-time alerts. For most people with type 2 diabetes on insulin, the FreeStyle Libre 3 offers the strongest combination of accuracy, longer sensor life, and lower cost. If you don’t use insulin at all, two newer over-the-counter options (Dexcom Stelo and Abbott Lingo) now let you track glucose without a prescription, at a fraction of the price.
Here’s how the main options compare and what actually matters when choosing one.
How CGMs Help With Type 2 Diabetes
A CGM is a small sensor you wear on your body (usually the back of your upper arm or abdomen) that measures your glucose levels continuously and sends readings to your phone. Instead of getting a single snapshot from a finger prick, you see how your blood sugar moves throughout the day, after meals, during exercise, and overnight.
For people with type 2 diabetes not on insulin, a real-world study published through the American Diabetes Association found that CGM users lowered their A1c by an average of 0.83 percentage points, compared to just 0.32 points for non-users. That’s a meaningful difference driven largely by behavior change: when you can see your glucose spike after a specific meal, you adjust what and how you eat. A separate pilot study found a clinically meaningful 10% increase in time spent in a healthy glucose range within the first week of use, suggesting people act on the data quickly.
FreeStyle Libre 3: Best Overall for Insulin Users
The FreeStyle Libre 3 is the smallest CGM currently available, measuring just 21 mm across and 2.9 mm thick, roughly the size of two stacked pennies. Each sensor lasts 14 days, which means fewer sensor changes per month and lower ongoing costs. It streams real-time glucose data to your phone without scanning, and it includes customizable high and low glucose alerts.
Accuracy is a strong point. In a head-to-head comparison published in the Journal of Diabetes Science and Technology, the Libre 3 had a mean absolute relative difference (MARD) of 11.6% against laboratory-grade analyzers. Lower MARD means closer to actual blood glucose values, and anything under 14% is considered clinically reliable. Against a standard home glucose meter, the Libre 3’s MARD dropped to 9.7%, making it one of the most accurate sensors tested.
Cost is where the Libre 3 pulls ahead for many people. Without insurance, the system runs about $2,000 per year, or roughly $150 per month with discount coupons for a pair of 14-day sensors. That’s significantly less than Dexcom’s prescription options.
Dexcom G7: Best for Alerts and Sharing
The Dexcom G7 is slightly larger than the Libre 3 (24 × 27.3 mm) but still compact enough to wear discreetly. Its biggest advantage is a 30-minute warm-up time, half of what the Libre 3 requires, so you get readings faster after applying a new sensor. Each sensor lasts 10 days, meaning you’ll change it more often.
Accuracy is comparable to the Libre 3. The G7 recorded a MARD of 12.0% against lab analyzers and 10.1% against a home meter. In practical terms, the difference between the two sensors is small enough that most users wouldn’t notice.
Where the Dexcom G7 stands out is its alert system and data-sharing ecosystem. The app offers predictive alerts that warn you before your glucose hits dangerous highs or lows, not just after. It also supports data sharing so a family member or caregiver can monitor your readings from their own phone. The G7 works directly with Apple Watch, letting you check glucose from your wrist without pulling out your phone.
The trade-off is cost. Without insurance or discounts, Dexcom G7 sensors run about $490 to $520 for a 30-day supply at retail. With discount coupons, that drops to around $185 per month for sensors alone. You may also need a one-time receiver purchase ($85 to $378 depending on source), though most people just use the smartphone app.
Over-the-Counter Options for Non-Insulin Users
If you manage type 2 diabetes with diet, exercise, or oral medications only, two newer CGMs are available without a prescription. These are designed specifically for people who don’t need insulin and want glucose data to guide lifestyle decisions.
The Abbott Lingo uses the same sensor technology as the Libre 3, lasting 14 days per sensor. It includes optional high and low glucose alerts and trend arrows showing which direction your blood sugar is heading. Pricing is straightforward: $49 for a single 14-day sensor, $89 for two sensors, or $249 for six. That works out to roughly $49 to $42 per month depending on the package you choose.
The Dexcom Stelo lasts 15 days per sensor and also streams real-time readings to a smartphone app. It’s specifically FDA-approved for people 18 and older with type 2 diabetes who don’t take insulin. The key limitation is that the Stelo offers very limited alerts. It won’t sound alarms for high glucose, low glucose, or rapid changes. It’s designed more as a tracking and learning tool than a safety device.
For someone who simply wants to understand how food, exercise, and stress affect blood sugar, either OTC option costs a fraction of what prescription CGMs run. The Lingo is the better choice if you want alerts. The Stelo is reasonable if you just want to observe trends.
Eversense E3: The Long-Term Implant
The Eversense E3 takes a completely different approach. Instead of a stick-on sensor you replace every 10 to 14 days, a healthcare provider inserts a tiny sensor under your skin that lasts up to 180 days, six full months. You wear a small transmitter on your arm over the implant site, and it sends data to your phone.
This option makes sense if you find frequent sensor changes irritating or if adhesive patches cause skin reactions. The downside is that both insertion and removal require an in-office procedure, so you’ll need to visit your provider at least twice a year for the sensor alone. The Eversense E3 is typically reserved for people on intensive insulin therapy and is less commonly prescribed for type 2 diabetes managed with oral medications.
What Insurance and Medicare Cover
Most private insurance plans cover at least one CGM brand for people with diabetes who use insulin, though copays vary widely. The more important question for many type 2 patients is Medicare coverage, since a large portion of the type 2 population is 65 or older.
Medicare covers CGMs and related supplies if you meet two conditions: you take insulin or have a documented history of low blood sugar episodes, and your healthcare provider confirms you’ve been trained to use the device as prescribed. Your provider must evaluate your condition and formally decide you qualify before writing the prescription. If you manage type 2 diabetes without insulin and haven’t experienced hypoglycemia, Medicare generally won’t cover a prescription CGM, making the OTC options a more practical path.
How to Choose
Your decision comes down to a few practical questions. If you use insulin and want the lowest ongoing cost, the FreeStyle Libre 3 is hard to beat at roughly $150 per month out of pocket. If you prioritize predictive alerts, Apple Watch compatibility, or the ability to share data with a caregiver, the Dexcom G7 justifies its higher price. Both are accurate enough that sensor precision alone shouldn’t drive your choice.
If you don’t use insulin and want to learn how your habits affect your glucose, the Abbott Lingo at $49 per sensor gives you the same core technology as the Libre 3 with optional alerts, no prescription required. And if you’re on intensive insulin therapy and tired of replacing sensors every two weeks, the Eversense E3’s six-month implant eliminates that hassle entirely.