Dexcom 5 almost always refers to the Dexcom G5 Mobile CGM, a continuous glucose monitor launched in 2015 and discontinued in the United States in 2022. It was the first CGM the FDA cleared for insulin dosing without a confirmatory fingerstick, a milestone that helped normalize CGM use. Current Dexcom users have moved on to G6, G7, or the over-the-counter Stelo.
What the Dexcom 5 Was
The Dexcom G5 Mobile System consisted of three parts:
- A disposable sensor worn on the abdomen or (off-label) upper arm, with a tiny filament inserted under the skin.
- A reusable Bluetooth transmitter that snapped onto the sensor and lasted about three months.
- A dedicated receiver or the Dexcom G5 Mobile smartphone app that displayed glucose values every five minutes.
Sensor wear time was 7 days (official), though many users wore them longer off-label. The system required two fingerstick calibrations per day using a standard meter — typically morning and evening — to keep the sensor aligned with blood glucose.
Regulatory Significance: The First iCGM for Dosing
In December 2016, the FDA expanded the G5’s indication, making it the first CGM cleared for non-adjunctive use — meaning users could dose insulin directly from the CGM reading without first confirming with a fingerstick. This was a turning point for CGM adoption. Insurance coverage expanded shortly after, and the device reshaped daily life for many people with type 1 diabetes.
For clinicians, the G5 also enabled Dexcom Share, which let caregivers view a loved one’s glucose remotely on a phone. Parents of children with type 1 diabetes routinely describe the introduction of Share as life-changing.
How the Dexcom 5 Worked in Daily Use
- Apply the sensor to a clean, dry area of the abdomen using the one-handed applicator.
- Snap the reusable transmitter onto the sensor housing.
- Pair the transmitter to the receiver or smartphone app via Bluetooth.
- Wait 2 hours for warm-up.
- Perform two fingerstick calibrations daily and enter the values.
- Use glucose values and trend arrows to make insulin, food, and activity decisions.
- Replace the sensor after 7 days.
The G5 offered adjustable high and low alerts, a rate-of-change alarm, and a distinctive “urgent low soon” predictive alert. These features were novel in 2015 and set user expectations for every subsequent CGM.
Dexcom 5 Accuracy in Perspective
G5 pivotal trial data showed a mean absolute relative difference (MARD) of around 9 percent against YSI lab reference when calibrated twice daily. That was excellent performance at the time. Modern successors have improved:
| Device | Launch Year | Wear Time | Adult MARD | Calibration Required? |
|---|---|---|---|---|
| Dexcom G5 | 2015 | 7 days | ~9.0% | Yes (twice daily) |
| Dexcom G6 | 2018 | 10 days | ~9.0% | No (factory calibrated) |
| Dexcom G7 | 2023 | 10 days | ~8.2% | No |
| Dexcom Stelo (OTC) | 2024 | 15 days | ~10.0% | No |
Why the Dexcom 5 Was Discontinued
Dexcom officially retired the G5 in the United States in 2022. The company cited the wider adoption of G6 and G7 and the need to streamline manufacturing. Factory calibration, longer wear time, a smaller profile, and updated iOS/Android apps made G6 and G7 strictly better for most users. Insurance plans followed Dexcom’s lead and shifted coverage.
If you have old G5 supplies on a shelf, check expiration dates carefully. Sensors stored past their labeled life may read inaccurately, and transmitters lose battery over time even unused. Transition to G6 or G7 with your clinician.
Who Benefits from a Modern Dexcom
The ADA Standards of Care recommend CGM for everyone with type 1 diabetes and for anyone with type 2 diabetes who uses multiple daily insulin injections or an insulin pump. Evidence also supports use in non-insulin type 2 diabetes and, increasingly, in prediabetes for education and behavior change.
If you are thinking about a Dexcom for prediabetes or borderline glucose levels, the over-the-counter Stelo is a low-friction entry point. For insulin-treated diabetes, G7 with smartphone and smartwatch integration is the current gold standard. Pair either with the broader habit changes in our treatment hub.
Historical Note for Collectors and Researchers
The G5 remains an important device in the history of diabetes technology. Research papers, clinician training modules, and older YouTube tutorials still reference it. If you are reviewing a study that used the G5, note that calibration requirements and 7-day wear time differ from current devices, which affects real-world comparisons.
The Bottom Line
Dexcom 5 usually means the Dexcom G5 Mobile CGM, which the FDA cleared in 2015 and Dexcom discontinued in 2022. It was the first CGM cleared for insulin dosing without fingersticks and paved the way for today’s factory-calibrated sensors. If you are still on G5 or considering it, switch to G6, G7, or Stelo with your clinician’s guidance.
Medical disclaimer: This article is educational and is not medical advice. Talk with your healthcare provider before starting, stopping, or changing any glucose-monitoring device.
