Historically, patients who wished to monitor their blood sugar levels at home would utilize a glucometer, which requires a small blood sample to be applied to a testing strip to obtain a reading. For some patients with diabetes, it can be a labor-intensive process that leads to non-adherence, sore fingers, and frustration.
A newer technology, known as a continuous glucose monitor (CGM), has provided a seamless and efficient method for monitoring blood sugar levels in patients with type 1 and type 2 diabetes. Although the first CGM was approved by the FDA in 1999, these innovative devices have only recently gained popularity, thanks to decreased costs and improved usability.
Continuous glucose monitors have allowed individuals to monitor their diabetes in real-time, providing immediate feedback based on activity levels, dietary habits, and medication adjustments. Continuous glucose monitors (CGMs) have made monitoring diabetes more efficient, safer, and more enjoyable. This article explores the most advanced CGM options in 2025, their key features, and tips to help you choose the best device for your lifestyle.
What is a CGM Monitor and How Does It Work?
A continuous glucose monitor is a device that tracks and monitors blood sugar levels in real-time. At a minimum, most CGMs include a reader and sensor, which connect together through Bluetooth technology. Some CGMs may also include a transmitter, which is responsible for wirelessly sending the glucose data from the sensor to the reader. In some older CGM models, the transmitter was a separate piece that had to be attached to the sensor once it was placed on the body. With newer models, the transmitter is integrated into the sensor and is neither visible nor accessible. Additionally, with new models, a smartphone can act as the reader through one of the approved applications, which can be downloaded onto your phone. This provides even more convenience, given that cell phones have become such an integral part of our daily lives.
Reviewing Different Types of CGM Monitors
Several continuous glucose monitors are currently available, each with its own advantages and disadvantages. The following companies currently manufacture continuous glucose monitors that the FDA approves:
- Abbott
- Dexcom
- Medtronic
- Eversense
Continuous glucose monitors do require a prescription from your doctor. There is only one continuous glucose monitor available without a prescription, called the Dexcom Stelo.
Several companies manufacture CGM devices, which are available for purchase online, including Nutrisense, Levels Health, and Signos. It is common for these companies to charge a monthly fee for the sensors and coaching. However, be cautious about using continuous glucose monitoring devices that the FDA has not approved, as the accuracy and claims have not been reviewed.
Most CGM systems can be paired with an application that can be downloaded onto a smartphone. Once a login is created and the sensor is paired with the phone, the application will begin tracking and recording real-time blood sugar levels, after a short warm-up period for calibration.
Dexcom CGM
The G6 and G7 are the latest Dexcom CGM models, with the Dexcom G7 CGM system being the most advanced and user-friendly model. Historically, Dexcom models had a few disadvantages to their CGM systems:
- The transmitter was a separate component, making the setup process complex and confusing for patients
- The sensors only lasted 10 days, requiring a new sensor every 10 days.
With the latest models, Dexcom has made some significant improvements in response to some of these known issues. The Dexcom G7 model can be used with either a dedicated reader or a smartphone app, depending on user preference. Additionally, a new Dexcom G7 15-day sensor was recently cleared by the FDA as of March 2025, allowing for less frequent sensor changes.
The Dexcom Stelo was recently FDA-approved in March 2024 but did not become available until the Summer of 2024, and it can now be purchased online. Unlike the Dexcom G6 and G7, which are approved for individuals aged two and older, the Dexcom Stelo is only approved for individuals 18 years and older.
According to independent clinical trials, including the 2024 iCGM Accuracy Study, Dexcom is considered one of the most accurate CGMs. However, recent head-to-head studies have also demonstrated similar accuracy, specifically compared to the Freestyle Libre CGM system.
Freestyle Libre CGM
The Freestyle Libre 2 Plus and Libre 3 Plus are the two latest models manufactured by Abbott. Previous models, the Libre 2 and Libre 3, are being discontinued and will be available until September 2025, according to Abbott. Abbott has encouraged patients to begin transitioning to the Libre 2 and 3 Plus models, which have extended 15-day wear time and compatibility
Advantages of the Freestyle Libre CGM system include:
- Glucose reading frequency every minute, compared to every 5 minutes for some other CGMs
- Small sensor size
The Freestyle Libre CGM models are recommended to be inserted into the back of the upper arm, which may be exposed at times. Some patients may prefer a more hidden sensor, such as one placed on the abdomen. Additionally, some studies have shown the Dexcom G7 to be the most accurate continuous glucose monitor (CGM) on the market, providing greater confidence and stability when controlling blood sugar levels.
Eversense CGM
Approved by the FDA in 2024, Eversense introduced the first one-year continuous glucose monitor (CGM). The one-year sensor is inserted under the skin by a healthcare professional and replaced annually. Patients are supplied with a transmitter that is placed on the body using a silicone-based adhesive available in both clear and white color options. Eversense provides enough adhesives so that patients can use a new one each day with the transmitter, allowing them to remove the transmitter if they choose.
A common issue with other CGMs is compression lows, which occur when there is a sharp drop in readings after a period of steady readings due to the sensor being compressed. This most often occurs when individuals lie down or are sleeping, leading to false lows. Eversense claims their CGM system causes almost no compression lows, a potential benefit for users.
Eversense is approved for individuals 18 years or older, making it difficult to obtain for pediatric patients or those with type 1 diabetes.
Other Popular CGM Devices
Other notable CGMs gaining popularity in 2025 include devices from Medtronic, such as the Guardian 4 Sensor, and newer wearable platforms that integrate CGM data with insulin pumps and fitness trackers. These are especially useful for patients using closed-loop systems or advanced hybrid insulin delivery.
| Freestyle Libre 2 Plus | Freestyle Libre 3 Plus | Dexcom G6 | Dexcom G7 | Dexcom Stelo (OTC) | Eversense E3 | Eversense 365 | |
| Insertion Site | Arm | Arm | Abdomen | Abdomen or arm | Arm | Arm (implanted under the skin) | Arm (implanted under the skin |
| Duration of sensor wear | 15 days | 15 days | 10 days | 10 days* | 15 days | 180 days | 365 days |
| Warm-up time | 1 hour | 1 hour | 2 hours | 30 minutes | 30 minutes | 24 hours | 24 hours |
| Method of insertion | self-insertion | self-insertion | self-insertion | self-insertion | self-insertion | Requires office-based procedure | Requires office-based procedure |
*The newer Dexcom G7 that was recently FDA-approved has a sensor wear time of 15 days and is predicted to be available later in 2025.
CGM Cost Breakdown
Commercial Insurance
Many commercial insurance plans cover continuous glucose monitors for individuals with type 2 diabetes who take insulin or have problematic hypoglycemia (low blood sugar). Depending on the type of insurance, patients may have a copay each time they pick up a prescription of sensors.
Medicare
Medicare Part B may cover a continuous glucose monitor through a durable medical equipment (DME) supplier if patients with type 2 diabetes are being treated with insulin or are experiencing problematic hypoglycemia. Specific documentation, such as recent office visit notes and CGM training, is required from your doctor for the CGM to be covered by insurance.
Medicaid
Each state’s Medicaid plans are different, and coverage varies. Similar to Medicare and commercial insurance, specific criteria may be required for the CGM to be covered. Check with your state’s medicaid plan to determine if CGMs are a covered benefit.
Cash
The price of continuous glucose monitors can be expensive, especially if an individual is paying cash, with costs ranging from $200 to $250 per month for a set of two sensors. Online coupons or patient-assistance programs may be used to reduce the cost of continuous glucose monitors.
How to Get a CGM Device
If you are interested in tracking blood sugars for health reasons or are pre-diabetic, the OTC Dexcom Stelo is available for purchase online without a prescription.
For those with type 1 or type 2 diabetes, ask your doctor about obtaining a continuous glucose monitor. It is recommended to review how to place the sensor initially to get more comfortable doing it by yourself in the future. Additionally, the CGM applications contain valuable data and reports that might help you better understand the changes in your blood sugar levels.
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Choosing the Right CGM for Your Needs
When selecting a CGM, consider the following:
- Accuracy and frequency of readings
- Wear time and sensor insertion site
- Device visibility and comfort
- Smartphone compatibility and app features
- Out-of-pocket costs and insurance coverage
Your lifestyle, diabetes type, and technology preferences should guide your choice. A discussion with your healthcare provider can help match the device with your goals.
CGM for Diabetes: Real-Life Benefits
Data show that continuous glucose monitors, compared to usual care, result in a variety of benefits, including reduced overall hypoglycemia, fewer episodes of severe hypoglycemia, increased patient satisfaction, and an improvement in A1c levels. They also enable early detection of glucose fluctuations, allowing for more proactive insulin adjustments, improved diet decisions, and better nighttime safety.
Final Thoughts: Finding the Best CGM for You
Continuous glucose monitors are transforming diabetes care by providing real-time insights, improving glycemic control, and increasing freedom in daily life. They reduce the need for frequent fingersticks, provide data that helps patients and providers make informed decisions, and improve safety by alerting users to high or low blood sugar levels. The growing availability of CGMs—now including over-the-counter options like the Dexcom Stelo—means that more people can access these benefits without having to jump through insurance hurdles. Whether you’re managing type 1 diabetes, type 2 diabetes, or simply want to monitor your metabolic health, there’s likely a CGM that can fit your needs and preferences.
As CGM technology continues to evolve, the differences between devices are becoming more nuanced, ranging from sensor wear time and app design to accuracy and integration with other devices. Choosing the right Continuous Glucose Monitor (CGM) involves balancing convenience, clinical needs, and cost. Discuss your options with your healthcare provider and consider starting with a trial period, if available. With the right CGM, you can take a more active role in managing your health and potentially improve both your outcomes and quality of life.
Frequently Asked Questions
