Dexcom ONE+

The Dexcom ONE+ is Dexcom's simplified, lower-cost real-time CGM, sold outside the US — in the UK, Europe, and the wider EMEA region. It launched in February 2024 in Spain, Belgium, and Poland (with the Netherlands following the week after) and rolled out across more EMEA markets through the year.¹ It is the successor to the original Dexcom ONE, and the key upgrade is the sensor itself: ONE+ uses the same hardware platform as the Dexcom G7, where the older ONE was built on the G6.²

How it works and how accurate it is. A small all-in-one sensor sits on your arm or abdomen, reads glucose in the fluid just under the skin, and sends a value to your phone every few minutes. Because it shares the G7 sensor, its registrational accuracy is the G7's: in the pivotal study, arm-worn sensors had a MARD (mean absolute relative difference — the average gap between sensor and lab blood glucose) of 8.2%, and abdomen 9.1% — single-digit, dose-from accuracy.³ A separate study of ONE+ specifically, in critically ill cardiac-ICU patients (a hard test case, with oxygen and blood-pressure drugs on board), found a MARD of 11.6%, with 99.6% of readings in the clinically safe zones — reassuring real-world performance even under stress.⁴ Like every current CGM, it reads interstitial fluid, so a ~10–15 minute physiological lag behind a fingerstick is unavoidable, especially when glucose is moving fast.

Wear, warm-up, calibration. Each sensor lasts up to 10 days, with a 12-hour grace window to swap sensors.⁵ Warm-up is 30 minutes — far quicker than the 2-hour warm-up on the old ONE and G6.⁶ It is factory-calibrated, so no fingerstick calibrations are required, though optional manual calibration is available if you want it.⁷

Alerts. You get customizable high and low alerts, including a low-glucose alert you can set (for example, below 3.9 mmol/L for more than 30 minutes), plus a "delay 1st high" option to cut early-morning alert fatigue.⁶⁵ It does not carry the G7's full predictive alert suite (such as the "urgent low soon" early warning).

What it works with — and what it doesn't. This is the deliberate trade-off. ONE+ is standalone: it displays on a compatible iOS or Android phone (and a paired watch), but it does not drive insulin pumps, does not power automated insulin delivery (AID) systems, and is not a supported sensor for the official DIY loops. If you want pump automation, Dexcom points you to the G7 instead.⁸ There is no ketone sensing — glucose only.

Who it's for, and cost. It's indicated for ages 2 and older, including during pregnancy, for type 1, type 2, and gestational diabetes.⁵ It's marketed as Dexcom's most affordable real-time CGM in the UK, sold either per 10-day sensor or on a monthly/quarterly subscription, and it is prescribable on the NHS.⁹ It is not sold in the US.

What's coming. Following the G7's move to a 15-day sensor, a longer 15-day wear time has been signalled for the ONE+ line, which would lower the per-day cost further; treat this as expected rather than confirmed until Dexcom announces a regulatory clearance.¹⁰

References

1. Dexcom. Dexcom Launches Dexcom One+ Bringing Powerful, New Diabetes Management Technology to More People. Dexcom investor news (2024). https://investors.dexcom.com/news/news-details/2024/Dexcom-Launches-Dexcom-One-Bringing-Powerful-New-Diabetes-Management-Technology-to-More-People/default.aspx ↩

2. Dexcom. The New Dexcom ONE+ (product page, NZ): "Results obtained with Dexcom G7, which shares the same hardware platform as Dexcom ONE+." (2024). https://www.dexcom.com/en-nz/dexcom-oneplus-cgm-system ↩

3. Garg SK, Kipnes M, Castorino K, et al. Accuracy and Safety of Dexcom G7 Continuous Glucose Monitoring in Adults with Diabetes. Diabetes Technol Ther 24(6):373–380 (2022). PMID 35157505. https://doi.org/10.1089/dia.2022.0011 ↩

4. Hohendorff J, Zawislak B, Adamczyk-Hohendorff M, et al. Accuracy of Dexcom One+ in Patients with Diabetes or Stress Hyperglycemia Hospitalized in Cardiac Intensive Care Unit. Diabetes Technol Ther (2026). PMID 41574585. https://doi.org/10.1177/15209156251407717 ↩

5. Dexcom. Dexcom ONE+ FAQs — 10-day wear + 12-hour grace; ages 2+ including pregnancy; iOS/Android app; settable low alert (2024). https://www.dexcom.com/en-nz/faqs/dexcom-one-plus ↩ ↩² ↩³

6. Dexcom. Introducing Dexcom ONE+ CGM — 30-minute warm-up vs 2-hour on ONE/G6; customizable high/low alerts; arm and abdomen wear (2024). https://www.dexcom.com/en-GB/blog/introducing-dexcom-one-plus ↩ ↩²

7. Dexcom. The New Dexcom ONE+ (Estonia product page): "Factory calibrated. Optional calibration for added flexibility." (2024). https://www.dexcom.com/en-ee/dexcom-one-plus ↩

8. Dexcom. The New Dexcom ONE+ (product page, NZ): directs users seeking insulin-pump (Tandem) integration to the Dexcom G7 — confirming ONE+ is standalone monitoring (2024). https://www.dexcom.com/en-nz/dexcom-oneplus-cgm-system ↩

9. Dexcom. Dexcom ONE+ Sensor (UK shop): single 10-day sensor, or monthly/quarterly subscription (2024). https://www.dexcom.com/en-gb/dexcom-shop/dexcom-one-plus ↩

10. Diabetech. Dexcom ONE+ CGM — What You Need to Know — reports that a 15-day weartime is expected in the future for the Dexcom ONE+ (secondary source; not yet a confirmed regulatory clearance). https://www.diabetech.info/p/dexcom-one-cgm-what-you-need-to-know ↩