Dexcom G7 15-Day

The G7 15-Day is Dexcom's longer-wearing G7. It is the same kind of small, all-in-one sensor people already know from the standard G7, but a new glucose algorithm stretches each sensor to up to 15.5 days of wear (15 days plus a 12-hour grace window to swap sensors).¹ That ties it with Abbott's FreeStyle Libre 3 Plus for the longest nominal wear time (15 days) of any CGM on the market — among the longest-wearing sensors available.¹² It does not require fingerstick calibration — it is factory-calibrated and starts giving readings once warm-up finishes.³

How accurate is it? In the pivotal study of 130 adults (about 87% with type 1), the G7 15-Day had an overall MARD of 8.0% — meaning readings landed, on average, within about 8% of lab glucose — across more than 20,000 paired measurements over the full 15.5 days.⁴ That is the lowest MARD Dexcom has reported and among the best for any sensor cleared to the FDA's stricter "iCGM" standard.¹ In the trial, 87.7% of readings fell within 15 mg/dL (below 70) or 15% (at or above 70) of the lab value, and the sensor stayed accurate from day 1 through day 15.⁴ Dexcom does not publish a separate hypo-range MARD; the iCGM clearance itself certifies that low-glucose accuracy meets FDA special controls.⁵

Wear, warm-up and calibration. Each sensor warms up in 60 minutes — longer than the standard G7's ~30 minutes, the trade-off for the extra five days of wear.³ No routine fingersticks are needed.³ One honest caveat: in the trial about 74% of sensors lasted the full 15 days, so roughly 1 in 4 may end early — worth knowing if your supply is rationed.⁴

Alerts and predictive features. It keeps the G7's customizable high/low alerts and the predictive Urgent Low Soon alert that warns before you actually go low.⁶

What it works with. Readings go to a phone or receiver and can stream directly to an Apple Watch without the phone nearby, like the rest of the G7 line.³ On the do-it-yourself side, the open-source Loop app supports the Dexcom G7.⁷ For automated insulin delivery, compatibility was rolling out at launch: the iLet Bionic Pancreas and Omnipod 5 were targeted first, with Tandem to follow shortly after — so AID support was slightly behind the mature standard G7 early on.⁸ It is water-resistant (submersible to 2.4 m for 24 hours).⁶ It senses glucose only — no ketone sensing.⁹

Who it's for, and where. Cleared for adults 18 and older; the standard G7 stays available for ages 2+.⁵ It is US-only for now, launched December 1, 2025, with no UK/EU/Canada/Australia/Japan availability yet.⁸ Out-of-pocket cost without insurance is significant, as with all Dexcom sensors.

What's coming. Dexcom has been explicit that 15-day wear is now its baseline going forward — its next-generation G8 uses the same 15-day platform, is about 50% smaller than the G7, and has ketone and multi-analyte sensing on its roadmap (not at first launch).⁹ In other words, the 15-Day isn't a one-off; it's the direction the whole product line is moving.

References

1. Dexcom, Inc. Dexcom G7 15 Day Receives FDA Clearance: the Longest Lasting Wearable and Most Accurate CGM System (press release, 10 Apr 2025). https://investors.dexcom.com/news/news-details/2025/Dexcom-G7-15-Day-Receives-FDA-Clearance-the-Longest-Lasting-Wearable-and-Most-Accurate-CGM-System/default.aspx ↩ ↩² ↩³

2. American Diabetes Association. FreeStyle Libre 3 and FreeStyle Libre 3 Plus CGM System — Consumer Guide (Sensor Duration: 15 days for the FreeStyle Libre 3 Plus). https://consumerguide.diabetes.org/products/cgms/freestyle-libre-3-and-freestyle-libre-3-plus ↩

3. Dexcom. New Dexcom G7 15 Day CGM: Longer Wear Time, More Accuracy. https://www.dexcom.com/en-us/all-access/dexcom-cgm-explained/new-g7-15-day-cgm ↩ ↩² ↩³ ↩⁴

4. Garg SK, Bailey TS, Castorino K, et al. Accuracy of the 15.5-Day G7 iCGM in Adults with Diabetes. Diabetes Technology & Therapeutics 2025;27(6):430–438 (per PubMed). PMID 40108991. https://pubmed.ncbi.nlm.nih.gov/40108991/ ↩ ↩² ↩³

5. U.S. FDA. 510(k) K243214 — Dexcom G7 15 Day Continuous Glucose Monitoring System (substantial equivalence, product code QBJ / iCGM, 21 CFR 862.1355; decision 9 Apr 2025). https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/QBJ/K243214 ↩ ↩²

6. American Diabetes Association. Dexcom G7 and G7 15 Day CGM System — Consumer Guide. https://consumerguide.diabetes.org/products/cgms/dexcom-g7-and-g7-15-day-cgm-system ↩ ↩²

7. LoopDocs. Compatible CGM (Dexcom G7 support in the open-source Loop app). https://loopkit.github.io/loopdocs/build/cgm/ ↩

8. Dexcom, Inc. Dexcom G7 15 Day Continuous Glucose Monitoring System to Launch on Dec. 1 in the United States (press release via Business Wire/Yahoo Finance, 20 Nov 2025). https://finance.yahoo.com/news/dexcom-g7-15-day-continuous-133000806.html ↩ ↩²

9. Drug Delivery Business News. Dexcom unveils next-gen G8 CGM system — CEO Jake Leach: 15-day wear is the baseline for all sensors going forward; G8 ~50% smaller with ketone/multi-analyte sensing on the roadmap. https://www.drugdeliverybusiness.com/dexcom-unveils-next-gen-g8-cgm/ ↩ ↩²