Understanding CGM Sensors: How Long Do They Last?

Continuous glucose monitoring (CGM) is an integral part of diabetes management, giving individuals with diabetes a way to track their blood glucose levels in real-time. Glucose levels can fluctuate throughout the day due to various factors, making it difficult to stay on top of our glycemic control. This is where CGM sensors come in – they provide a convenient, accurate, and reliable way to monitor glucose levels.

Understanding the lifespan of your CGM sensor is essential for successful diabetes management. Knowing when to replace a sensor can help ensure accurate readings and minimize the risk of user errors or inaccurate results. It can also help prevent costly and potentially harmful situations, like running out of supplies or being forced to switch to a different sensor type. Exploring the factors that influence CGM sensor lifespan can help you decide when to replace your device.

If you’re using a CGM, you’ve probably heard mixed messages about the lifespan of your sensor. To clear up any confusion, explore the factors that affect CGM sensor life in this article.

The Role of CGM Sensors in Continuous Glucose Monitoring

CGM sensors are small, unobtrusive devices that measure glucose levels in the interstitial fluid (the fluid between cells) and transmit this data to a separate display device. This allows individuals with diabetes to monitor their glucose levels continuously throughout the day without taking frequent fingersticks or other measurements. This can provide a more comprehensive view of glucose levels and enable individuals to make informed decisions about their diabetes management.

For example, CGM sensors can be combined with an insulin pump or other diabetes medications to help manage blood glucose levels daily. The data collected from the CGM can identify trends in glucose levels and provide insight into how lifestyle choices or medication changes affect your diabetes management.

Benefits of CGM Sensors

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CGM sensors have many advantages over traditional methods of monitoring glucose levels. For one, they provide real-time data that can be used to identify trends and make adjustments to diabetes management quickly. This can be especially beneficial for those with type 1 diabetes, who must frequently monitor their glucose levels and adjust their insulin doses.

CGM sensors also are much less invasive than traditional methods, such as fingersticks. This can be beneficial for those who find fingersticks difficult or painful. It also eliminates the need to carry around a blood glucose monitoring device and test strips, which can be inconvenient.

Finally, CGM sensors allow individuals to track their glucose levels without taking multiple daily measurements. This can free up time for other activities and make diabetes management more convenient. When used in combination with an insulin pump, CGM sensors can even automate insulin dosing decisions based on real-time glucose readings.

Statistics on CGM Technology Adoption

The prevalence and adoption of CGM technology have grown significantly in recent years. A study in 2014 showed that while some people were hesitant to use CGM systems, there were also some clear benefits associated with using them. Two surveys involving paid participants with type 1 and 2 diabetes revealed that most participants used the system to better manage their diabetes.

In survey 1, 90% of participants reported using CGM less than four times a day to manage their diabetes, while in survey 2, 78% used it less than three times a day. This suggests that, despite the barriers to adoption, CGM has become a routine part of diabetes management for many people.

In 2022, another study revealed that the adoption of CGM had greatly increased. Canadians aged 18-35 with type 1 diabetes were the participants using CGM sensors. The study found that fewer people were living with complications and even fewer deaths related to diabetes, indicating that CGM was being used effectively and prompting steps to implement universal CGM use.

Adopting CGM technology has become much easier in recent years, as more devices have become available and the cost of these systems has decreased. The current cost estimates for CGM systems are approximately $500 monthly or $6000 per year plus supplies, which is still a sizable expense but less than it used to be.

How CGM Sensors Work

A. Provide an overview of the technology behind CGM sensors

CGM sensors use a combination of technology to measure glucose levels in the interstitial fluid. By placing a tiny sensor beneath the skin, CGM systems can detect glucose levels in the body and transmit data to a receiver. This data helps track glucose levels and makes diabetes management decisions.

This technology uses a sensor containing an enzyme that oxidizes glucose molecules and produces electrical signals when exposed. As glucose levels fluctuate, these signals are detected and sent to a transmitter. The blood sugar data is then interpreted and displayed on a receiver.

The device has three main components: the sensor, transmitter, and monitor. These components measure glucose levels and transmit the data to a monitoring device.

The sensor is usually inserted under the skin, typically in the upper arm, thigh, or lower abdomen. The sensor measures glucose levels in the interstitial fluid and transmits this data to a transmitter. This sensor is usually waterproof and disposable and must be replaced every few days.

The transmitter uses radio waves to send the glucose data to a monitor or mobile device that displays the data in real-time. Still, some systems also allow manual data entry. There may also be a delay in data transmission from the sensor to the device.

The monitor displays the glucose trend over time and alerts users when their glucose levels are too high or too low. This allows individuals to make informed decisions about their diabetes management quickly and easily. Some systems may include additional features like data sharing or insulin dosing recommendations.

The Lifespan of CGM Sensors

Now that you understand the technology behind CGM sensors, you can explore how long they typically last. You should know that various factors can affect the lifespan of CGM sensors. Here are some of them:

Factors that Affect the Lifespan of CGM Sensors

1. Sensor type and brand

Different brands and types of CGM sensors have different lifespans. For example, regular sensors can last up to 14 days. These disposable sensors should be replaced after a few days to maintain accuracy and reliability. Their transmitters are also typically rechargeable and should be replaced every few months.

Some brands, like the FreeStyle Libre, don’t have reusable transmitters. When the sensor runs out, the entire device must be replaced. This type of device typically lasts two weeks or more. Some brands, like the Dexcom G6, can last up to 10 days, with their transmitters lasting up to 90 days. The plastic component of the device attaches to the transmitter, making the sensor easier to replace after a few days. These two brands are the most popular CGM systems, so choosing one of them can give you a better idea of how long your CGM sensor will last.

It’s important to carefully read the manufacturer’s instructions to determine your device’s sensor life expectancy. Some sensors may need to be replaced even sooner than the recommended timeframe if they become damaged or perform poorly.

2. Wear duration and adhesion

How long a sensor lasts depends on how well it is attached and worn. If it’s not adhered correctly or worn consistently, the sensor won’t be able to detect glucose levels accurately. The longer the sensor is worn, the more accurate it will be. If worn for too long, they can also become less accurate. The sensor will start giving inaccurate readings if worn for more than its allotted time. This is why it’s crucial to replace them as soon as they become worn or damaged.

Additionally, the adhesive on the sensor can impact its lifespan. If it’s not replaced often enough, the bond can become less effective and cause the sensor to come loose or fall off prematurely. This will result in inaccurate readings and the need to replace the sensor sooner than expected. Although adhesive patches are available to help keep the sensor in place, they must be replaced regularly to ensure accuracy.

3. Sensor accuracy and reliability

If you use a CGM system, accuracy and reliability are essential. If the sensor isn’t reliable, it won’t give you the data you need to make informed decisions about your diabetes management. Poor accuracy can also lead to inaccuracies in insulin dosing decisions, potentially resulting in danger or even death.

Improper maintenance and storage can also affect the accuracy and reliability of sensors. For example, storing your device at extreme temperatures (above or below room temperature) can cause the device to give inaccurate readings. Dexcom instructs its customers to store their devices between 36°F and 86°F, but not in a freezer. It is also essential to keep the device away from moisture, as humidity can also affect the accuracy of glucose readings. Storing between 10% to 90% relative humidity is recommended.

A reliable CGM sensor is essential for successful diabetes management. Some CGM systems are more accurate than others, so it’s important to research each device before purchasing.

Extending the Lifespan of CGM Sensors

If you want to extend the lifespan of your CGM sensors, you can do a few things. Depending on the type of device you have, you may be able to make certain adjustments or changes to optimize its longevity.

Strategies to Prolong

1. Proper site preparation and insertion techniques

When you insert a new sensor, preparing the site and using proper insertion techniques are important. This can help ensure the device stays in place longer and provide more accurate readings.

Before inserting the device, ensure the area is clean and dry. Gently rub the skin with an alcohol wipe before inserting the sensor. This will help create a better bond between the skin and the adhesive patch or tape to attach the device. If you’re using an adhesive patch, follow the instructions for proper placement.

Using a sterile needle or lancet is also essential for proper insertion. Insert the sensor slowly and at a 90-degree angle to reduce any discomfort or trauma to the skin. Use sterile gloves or other protective gear when inserting the sensor to reduce the risk of infection. Push it in just enough to secure it without puncturing the device.

Depending on the type of device, you may get additional instructions for proper insertion. Make sure you read all the instructions carefully before inserting the device and follow them as directed. For example, Dexcom has a start guide providing detailed instructions for inserting their sensors.

2. Optimizing sensor adhesion and durability

After insertion, it’s crucial to optimize the adhesion and durability of the sensor. Make sure you use an adhesive patch or tape designed to help secure the sensor. These patches or tapes should be replaced more frequently than the sensor, usually every two to seven days, depending on the type of adhesive used.

To extend the sensor’s life, avoiding any activities that could cause it to come loose or fall off is essential. This includes swimming, bathing for too long, and vigorous exercise. Always check the adhesive patch or tape to ensure it is securely attached before engaging in any activities. If it’s not, replace the adhesive before continuing.

3. Minimizing interference and sensor errors

Interference can also affect the accuracy of CGM sensors. One of the most common sources of interference is medication. Different medications can impact glucose readings. This also depends on the brand of the CGM system.

For one, Dexcom devices can give inaccurate readings when there is the presence of acetaminophen (Tylenol) and hydroxyurea. The sensor may mistake the acetaminophen for glucose, leading to a falsely high reading. Similarly, hydroxyurea can cause false highs, making it challenging to detect hypoglycemia.

Abbott, the FreeStyle Libre CGM systems manufacturer, lists Ascorbic acid (vitamin C) and salicylates (aspirin) as medications that can interfere with the device. These medications can cause false lows in their devices, making it challenging to detect hyperglycemia.

Sensor errors can also occur if the device fails to function properly or isn’t worn correctly. Ensure your CGM system is clean and free of dirt, debris, and moisture. Replace the adhesive patch regularly, depending on your device type. This can help minimize interference and optimize the accuracy of your CGM readings.

Users suggest that calibrating the device more frequently can also reduce errors. This means comparing your CGM readings to a fingerstick reading every few hours or testing it with a meter more often. This can help you quickly identify discrepancies and adjust your insulin dose accordingly.

Sensor Replacement and Maintenance

Of course, replacing your CGM sensor regularly is essential for accurate readings and maintaining good diabetes management. Many people use CGM systems to keep their blood sugar in check and avoid dangerous complications. As a result, being able to replace sensors quickly and easily is crucial. Here are the steps for replacing a CGM sensor:

  1. Remove the old sensor from your skin using an alcohol wipe or sterile gauze.
  2. Appropriately dispose of the old sensor by placing it in a biohazard container. This will help prevent any infection or contamination.
  3. Prepare the new sensor and the area where it will be inserted with an alcohol wipe, making sure to clean the area thoroughly.
  4. Insert the new sensor at a 90-degree angle and secure it with an adhesive patch or tape.
  5. Attach the transmitter to the sensor or connect it wirelessly, depending on your device type.
  6. Once the new sensor is in place, calibrate it using the instructions from your device manufacturer.
  7. Monitor the sensor regularly for any signs of error or inaccuracy and replace it as needed.

Depending on your device type, manufacturer guidelines and recommendations about sensor replacement frequency may vary. Dexcom recommends replacing their G6 sensors after ten days. This helps ensure the accuracy and reliability of the device. FreeStyle Libre, on the other hand, recommends replacing their sensors every two weeks for optimal accuracy.

Following manufacturer guidelines for sensor replacement frequency is essential to ensure your device functions correctly and provides accurate readings. Additionally, some brands may offer discounts on sensor replacements or have programs that allow you to receive free sensors if you meet specific criteria. These programs can help make CGM technology more accessible and affordable for those with limited financial resources.

As technology advances, so does the durability of CGM sensors. These days, CGM systems are designed to be more durable and better able to withstand the wear and tear of everyday activities.

For example, Abbott’s FreeStyle Libre 3 system is now designed to be smaller, more discreet, and more durable. The sensor itself is only four millimeters thick and about the size of two stacked pennies, making it easier for users to wear discretely.

Another example is Dexcom’s G7 system, designed to be 60% smaller than their G6 system. This device has a shorter warm-up period and is approved for use in pregnant women, including gestational diabetes. This device is designed to provide more accurate readings and improved comfort for users.

Other brands also work to make their CGM systems more durable and reliable. Medtronic’s Guardian Connect, for instance, is designed to be waterproof, so users can wear it while swimming or showering. Some devices are engineered to connect to insulin pumps and provide real-time glucose readings. This helps people with diabetes manage their blood sugar levels more efficiently.

User Experiences and Perspectives

Personal stories and testimonials from individuals using CGM sensors

  1. Kerry Sayles, a mother with type 1 diabetes, found Dexcom’s CGM system invaluable during her pregnancy. Suffering from morning sickness, she needed to be able to monitor her glucose levels continuously. The system allowed her to do this, giving her peace of mind and a feeling of being in control of her diabetes.
  2. Tanya P. has seen her A1C drop from over 14 to below seven since using the FreeStyle Libre 14-day sensor. She appreciates the convenience of quickly and easily monitoring her glucose levels. She now has a much better understanding of how food and other factors can affect her sugar levels and has regained control of her diabetes.
  3. Andrea Finden has a son with diabetes and is a big fan of her CGM system. She appreciates the alarms that sound if her son’s glucose levels get too high or low. Knowing that they will receive timely alerts gives her and her family peace and reassurance in case of any unexpected events.
  4. Joseph is a 43-year type 1 diabetes veteran and has drastically improved his glucose levels since using the FreeStyle Libre 14-day system. He can check his levels at any time, monitor trends, and reduce his usage of finger sticks. The freedom this has given him, with the improved overall health he’s seen, has been life-changing.

The lifespan of a CGM sensor can significantly impact the user experience and overall glucose management. Longer sensor life allows users to monitor their glucose levels more often and accurately. This can help people understand how different activities, such as exercise or food choices, impact their glucose levels. It can also help them identify patterns and trends contributing to their diabetes management.

So, monitoring glucose levels accurately and consistently is essential for successful diabetes management.

Online forums and community discussions on CGM sensor longevity

Many people who use CGM systems participate in online forums or communities to discuss their experiences and provide advice and tips for prolonging sensor life. Often, people will share their strategies for keeping their sensors in place longer and getting the most out of them.

Tips shared by users on various forums, such as Type2diabetes.com and diabetes.co.uk, include:

  1. Stick to a regular sensor replacement schedule that works for you.
  2. Use the correct type of adhesive patch or tape, depending on your device type and skin sensitivity, which can help extend the life of your sensor.
  3. Minimize physical contact with the adhesive patch or tape, as this can cause it to come loose.
  4. Apply a thin layer of medical tape to keep the adhesive patch or tape in place and reduce friction wherever possible.
  5. Avoid using lotions or creams around the adhesive patch, which can interfere with the device’s accuracy.

Comparing CGM Sensor Lifespans Across Brands

As mentioned, different CGM systems can have varying lifespans. For instance, Dexcom’s G6 system has a sensor lifespan of up to ten days, while the FreeStyle Libre system has a lifespan of up to 14 days. Medtronic’s Guardian Connect system has a lifespan of up to seven days, while Eversense’s E3 system has a lifespan of up to six months.

These sensor lifespans are based on manufacturer recommendations and may vary depending on the individual’s usage and lifestyle. It’s essential to research each device before purchasing and find the one that best suits your lifestyle and needs.

The difference in sensor lifespans can have a significant impact on user satisfaction. For example, if someone needs to replace their CGM sensor more often than the recommended timeframe, they may find it inconvenient and expensive. On the other hand, someone who can use their CGM system for longer may find it more cost-effective and beneficial.

Statistics show that CGM systems are becoming increasingly popular. According to a study, ethnicities such as non-Hispanic whites had higher rates of CGM use at 50% compared to non-Hispanic blacks or Hispanics between 18-38% as the lifespan of CGM sensors had improved over the years. Patients with private insurance also had a higher CGM usage rate at 57.2% compared to those with public insurance, which includes Medicaid or Medicare, at 33.3%.

The performance of CGM sensors has also significantly improved over time. Both the Libre FreeStyle 3 system and Dexcom G7 have improved in their mean absolute relative difference (MARD) scores, a metric to measure the accuracy of CGM systems. This higher accuracy gives users more confidence in their glucose readings compared to older versions.

Future Trends and Advancements in CGM Sensor Lifespan

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Current research and development in CGM sensors are focused on making the technology smaller to allow for better integration with the body and more accurate readings. This includes making sensors thinner, more waterproof, and longer lasting.

Improving the lifespan of CGM sensors can also help reduce the number of replacements needed and improve the user experience. Although there are already CGM systems available on the market with long sensor lifespans, such as Eversense’s E3 system, there is still more room for improvement.

Accuracy is another area in which CGM technology is undergoing research and development. Research is being done to improve the accuracy of glucose readings, reduce sensor errors, and minimize the delay between readings. This could help users better manage their glucose levels and reduce the risk of diabetes-related complications. For example, scientists are testing a sensor that uses nanotechnology to detect glucose levels. This non-invasive technology could help reduce the need for fingersticks and provide more accurate readings.

Finally, some initiatives aim to help make CGM devices more accessible worldwide. Plans by Dexcom to launch a cash-pay option for people who don’t use insulin in 2024 could make CGM technology more affordable and accessible to more people. This could be a major step forward in improving diabetes management on a larger scale. About 3-4 million people have had hypoglycemia problems, which could help reduce that number significantly.



Understanding the lifespan of CGM sensors is essential for successful diabetes management. Sensor lifespans can vary from device to device, and it’s necessary to research the options available and find one that suits your lifestyle and needs. Regularly replacing sensors following the manufacturer’s guidelines can help minimize interference and optimize accuracy.

Factors such as lifestyle, device type, and financial resources can all affect the lifespan of a CGM sensor. Recent advancements in CGM technology have made sensors thinner, more durable, and longer lasting. Research is also being done to improve the accuracy of readings and make CGM devices more accessible.

By staying informed about the latest trends and advancements in CGM sensor technology, people with diabetes can ensure they use the best device for their lifestyles and needs. Always follow manufacturer instructions for sensor replacement frequency and check with your healthcare provider if you have any questions or concerns.

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