Why Didn't My Dexcom G7 15 Day Sensor Last 15 Days?
Dexcom G7 15 Day is designed to provide up to 15.5 days of continuous glucose monitoring, making it the longest-lasting CGM available*†,1. In fact, in a recent study, over 81% of Dexcom G7 15 Day sensors with its new improved adhesive, achieved the full wear duration2-3. This is a testament to Dexcom’s innovations and advancements in sensor technology, but what happens when a sensor doesn’t make it all the way to day 15?
If a CGM sensor ends early, you may wonder what went wrong, whether you did something incorrectly, or whether you should be concerned.
The reassuring answer is that an early sensor end is not necessarily a sign of a defective sensor. In fact, there are several normal biological and everyday factors that can influence how long a CGM sensor lasts, and some of the technology designed to keep your glucose readings reliable can occasionally result in a sensor ending before day 15.
Most importantly, Dexcom is here to help if your sensor ends early. Contact Dexcom Technical Support to work with our team to see how to get an additional sensor at no cost without any limits.
How Dexcom G7 15 Day Works With Your Body
When you insert a Dexcom G7 15 Day sensor, a tiny sensor filament sits just beneath your skin and measures glucose levels in the interstitial fluid surrounding it. This allows the system to provide continuous glucose information throughout your wear session.
Like all wearable biosensors, the sensor interacts with your body's natural processes. After insertion, your body begins responding to the sensor filament as it would any foreign object. This is completely normal.
Over time, some people may develop a thin layer of tissue around the sensor filament. This natural immune response can make it harder for glucose to reach the sensor and may affect how long the sensor can continue performing. Because every person's body responds differently, wear experiences can vary from one user to another.
What Can Affect CGM Sensor Wear Duration?
Several factors can influence how long a CGM sensor lasts, and many are simply part of everyday life. These include:
- Individual biology and tissue response
- Glycemic variability
- Sensor placement and insertion site
- Sweat and skin type
- Exercise and physical activity
- Water exposure‡
- Friction from clothing or equipment
- Sleeping positions or pressure on the sensor
- Accidental bumps and impacts
In other words, a sensor’s wear time isn't determined by a single factor. It's the result of how your body, your activities, and the sensor work together over time.
Why Some Sensors End Early
At first glance, a sensor ending early may feel frustrating. However, it's important to understand that Dexcom G7 15 Day was designed to prioritize data reliability over wear duration.
Throughout every wear session, sophisticated Dexcom algorithms continuously monitor sensor performance behind the scenes. These built-in safeguards are designed to help ensure the glucose values you see to be accurate data.
In some cases, the system may determine that it can no longer confidently provide glucose information that meets Dexcom's accuracy standards. When that happens, the system may end the session early rather than continue displaying readings that could be less accurate.
The goal is simple: help ensure you're making decisions based on glucose information you can act on with confidence.
What You Can Do to Maximize Sensor Wear Time
While some factors are outside your control, there are a few steps that may help maximize the length of a sensor session:
- Follow the recommended insertion and placement guidelines in the Dexcom G7 15 Day User Guide.
- Apply the sensor to clean, dry skin.
- Use the overpatch included in the Dexcom G7 15 Day box with every sensor session.
- Rotate insertion sites between sessions.
- Be mindful of repeated pressure, rubbing, or friction from clothing, athletic gear, or equipment.
These practices can't eliminate all variability, but they can help support comfortable wear and strong adhesion throughout your session.
If Your Sensor Ends Early, We're Here to Help
The most important thing to remember is that an early sensor end does not automatically mean something went wrong. Some variability in wear duration is expected across all wearable biosensors and reflects a combination of biological and wear-related factors.
At Dexcom, we're committed to supporting you every step of the way. If your sensor ends early, contact Dexcom Technical Support. Our team can help evaluate your experience, provide troubleshooting guidance, and determine whether a replacement is appropriate.
The Bottom Line
Dexcom G7 15 Day was designed to provide the most accurate CGM reading for up to 15.5 days of wear*†,1., and built with intelligent guardrails that help prioritize reliable glucose information.
While some sensors may end before day 15 because of normal biological and wear-related variability, this is not necessarily a sign of a product defect. In some cases, it's evidence that the system's built-in programming are doing exactly what they were designed to do: helping you receive accurate glucose readings.
And if your sensor does end early, know that you're not on your own. Dexcom Technical Support is available to help, and Dexcom will replace sensor that did not meet the published standards at no cost.
Get started with Dexcom G7 15 Day
Are you living with diabetes and not using CGM? Talk to your doctor about Dexcom G7 15 Day. We can also help you get started with a free benefits check. Click the button below to send us some basic information.
*A study was conducted to assess the sensor life where 73.9% of sensors lasted the full 15 days. When using the product per the package labeling, approximately 26% of sensors may not last for the full 15 days. †Excludes implantable CGM systems. 1 Dexcom, Data on file, 2025. 2 Dexcom G7 15 Day User Guide. 3 Dexcom, Data on File, 2026. ‡The Dexcom G7 15 Day sensor is waterproof and may be submerged under eight feet of water for up to 24 hours without failure when properly installed.