A single Dexcom G6 sensor lasts up to 10 days. After that, the system automatically shuts off and stops providing glucose readings. You’ll need to remove the old sensor and insert a new one to continue monitoring. There’s no grace period or way to extend the session beyond that 10-day window.
What the 10-Day Session Looks Like
When you insert a new G6 sensor, it goes through a 2-hour warm-up period before it starts delivering readings. Once that warm-up finishes, your 10-day countdown begins. During that time, the sensor measures glucose levels continuously without requiring any finger-stick calibrations.
One common concern is whether accuracy drops off toward the end of those 10 days. Clinical data presented through the American Diabetes Association shows it doesn’t. The sensor’s accuracy on day 1 and day 10 is essentially identical, with error rates of 9.3% and 9.0% respectively. So readings on your last day are just as reliable as readings on your first.
As you approach the end of the session, your Dexcom app or receiver will notify you that the sensor is expiring soon. Once the 10 days are up, the sensor shuts off automatically and can’t be restarted. Dexcom explicitly states that sensors cannot be used beyond the 10-day limit.
The Transmitter Has Its Own Lifespan
The sensor and the transmitter are separate components, and each has a different lifespan. While each sensor lasts 10 days, the transmitter battery lasts about 3 months. That means you’ll go through roughly nine sensors before needing a new transmitter.
Starting about 3 weeks before the transmitter battery dies, you’ll see warnings counting down its remaining life. Once it drops below 10 days of battery, you won’t be able to start a new sensor session. Instead, you’ll see a “Pair New Transmitter” message. Planning ahead for transmitter replacement avoids gaps in your monitoring.
Keeping the Sensor Attached for All 10 Days
The 10-day limit is built into the software, but in practice, a lot of people lose their sensor early because the adhesive gives out. Sweat, water, oily skin, and friction from clothing can all peel the patch away before the session ends. A little prep work at insertion makes a big difference.
Start by cleaning the site thoroughly: wash with soap and water, let it dry, then scrub with an alcohol wipe and let it dry again. If you have residue from a previous sensor, use an adhesive remover first. Avoid placing the sensor where skin folds when you bend, where there’s body hair, or near your waistband. Rotate to a new site with every session.
When you apply the sensor, press the applicator firmly against your skin for 30 to 60 seconds before releasing and pushing the insertion button. After insertion, rub around the entire patch three times, using the back of your fingernail for extra pressure, and smooth out any wrinkles.
For extra security, Dexcom offers free overpatches that go on top of the sensor’s adhesive. You can order them through the G6 app or through Dexcom’s website. If your skin tends to be oily or you sweat heavily, put the overpatch on right after insertion. If your skin is drier, you can wait and add one only if the edges start peeling. Medical tape works as an alternative.
If you want to use a skin adhesive product like SkinTac under the patch, apply it around the sensor area but avoid the spot where the needle inserts. Let it dry completely before placing the sensor.
When a Sensor Fails Before 10 Days
Sometimes a sensor stops working before the 10-day session ends. You might see a “Sensor Failed” alert, meaning the sensor can no longer provide readings and needs to be replaced. This can happen for various reasons: the sensor filament may have bent during insertion, the sensor may have been placed in a poor location, or there may be a manufacturing defect.
If a sensor fails early, remove it and insert a new one. Dexcom’s support team will typically replace sensors that don’t last the full 10 days at no extra cost, so it’s worth contacting them when this happens.
Why You Can’t Restart a G6 Sensor
Some users look for workarounds to extend a sensor past 10 days, but Dexcom designs the G6 to prevent restarts. The sensor is engineered for a specific wear duration, and the enzyme coating on the sensor filament that reacts with glucose degrades over time. Using a sensor beyond its intended life means relying on readings that may no longer reflect your actual glucose levels, which is particularly risky if you use those readings to dose insulin. Dexcom’s official guidance is straightforward: replace the sensor after 10 days, every time.