Dexcom ONE+ Sensor Shows Major Glucose Reading Errors

I would like to share the serious problems I have experienced with Dexcom’s new glucose monitoring sensor, Dexcom ONE+. On August 24, 2026, I purchased one sensor from an authorized retailer in Ankara to try the product, but I experienced serious discrepancies in the readings from the very first use. When I contacted the support team, I was told that the product would be replaced under warranty and that a new sensor would be sent to me, but that the process would take approximately 10 days. Since I did not want to be left without a sensor, I had to purchase a second sensor from the same authorized retailer. In the meantime, the replacement sensor arrived earlier than expected and was delivered to me on the same day, so I ended up with two sensors.

When I applied the first sensor, I noticed that the sensor filament appeared to be defective and sent photos to the support team, after which a new service case was opened. When I applied the second sensor I had purchased, I experienced exactly the same problem again, and a replacement case was also created for that sensor. Since it was the weekend and I did not want to be left without a sensor, I purchased a third sensor from the authorized retailer. However, I experienced unacceptably large discrepancies with this sensor as well, even after calibrating it multiple times. For example, the sensor showed 64 mg/dL, indicating hypoglycemia, and repeatedly woke me up with alarms throughout the night, while a simultaneous finger-stick measurement showed 98 mg/dL.

When I contacted the support line again about this issue, I was faced with additional requests that made the process even more difficult, such as providing photos of the box and applicator. Even though I provided all the requested information and photos completely, I requested a refund as a consumer who had originally intended to try just one sensor but ended up having to purchase three sensors and suffered significant inconvenience due to the inaccurate readings. The support team told me that they did not handle refunds and provided me with the phone number of the company’s central office.

When I called the central office in the morning, I was told that my request would be forwarded to the appropriate person and that I would receive a call back, but no one contacted me. I called again the following morning and again that evening. Although notes were taken during these calls, I never received any follow-up. At this point, I feel that the process has turned into a completely discouraging experience, and I have been unable to find anyone willing to take responsibility for resolving the issue.

I currently have two unopened Dexcom ONE+ sensors that were sent as replacements, and I am also expecting one additional replacement sensor to be delivered. Because of the problems I experienced and the loss of confidence in the product, I have had to switch to a device from another brand, and Dexcom ONE+ has been a major disappointment for me. I request that all of the Dexcom ONE+ sensors I have be accepted for return and that I receive a full refund for all amounts I have paid to date.