The Dexcom G7 is a continuous glucose monitor (CGM) that tracks your blood sugar levels in real time, sending readings to your smartphone or smartwatch every five minutes without fingerstick tests. It’s a small, disposable sensor you wear on your body that measures glucose through a tiny filament just under the skin, designed primarily for people with type 1 or type 2 diabetes.
How the Sensor Works
The G7 is an all-in-one device, meaning the sensor and transmitter are combined into a single unit. You apply it with a one-click applicator that inserts a hair-thin filament under your skin at a 90-degree angle. The filament sits in the interstitial fluid just below the surface and continuously measures glucose concentrations, converting those readings into a number on your phone or receiver.
Once applied, the sensor needs a warmup period before it starts delivering data. The standard G7 requires about 30 minutes. The newer G7 15 Day version, which uses a different algorithm to support five extra days of wear, requires a 60-minute warmup. After that, you get automatic readings around the clock with no further calibration needed.
Where You Wear It
The approved placement depends on your age and which version you’re using. For adults and children ages 2 and older, the standard G7 goes on the back of the upper arm. Children between 2 and 6 can also wear it on the upper buttocks. The G7 15 Day sensor is currently cleared only for the back of the upper arm in adults 18 and older. Neither version is approved for abdominal wear.
Sensor Life and Water Resistance
The standard G7 lasts 10 days before it needs to be replaced. The G7 15 Day extends that to, as the name suggests, 15 days. When the sensor session ends, you peel off the old one and apply a fresh unit. Since the transmitter is built in, there’s no separate component to detach, charge, or reuse.
The sensor is waterproof and can be submerged in up to eight feet of water for as long as 24 hours without failure, so showering, swimming, and bathing are all fine as long as the sensor is properly applied.
What Changed From the G6
If you’re familiar with the previous Dexcom G6, the G7 represents a significant redesign. The on-body footprint is 60% smaller, which makes it less noticeable under clothing. The G6 used a separate transmitter that clipped into the sensor and lasted about three months. The G7 eliminates that by integrating everything into one disposable piece. The insertion angle also changed from 30 degrees to 90 degrees, and the applicator was simplified to a single button press. Even the packaging was reduced to cut down on waste.
Dexcom also redesigned the optional standalone receiver (for people who don’t want to use a phone), making it smaller with an easier-to-read display.
Alerts and Predictive Warnings
One of the most valuable features of the G7 is its alert system. You can set customizable high and low glucose alarms so the device notifies you before your levels move into dangerous territory. The Urgent Low Soon alert is particularly important: it predicts when your glucose is heading toward 55 mg/dL and warns you roughly 20 minutes before you’d reach that level. That window gives you time to eat fast-acting carbs or take other action before a serious low hits.
You can also set rate-of-change alerts that notify you when your glucose is rising or falling quickly, even if you haven’t crossed a specific threshold yet. All of these are adjustable, so you can fine-tune which notifications you receive and when.
Smartphone and Smartwatch Compatibility
The G7 connects via Bluetooth to the Dexcom G7 app on compatible iPhones and Android phones. What sets it apart from many CGMs is its Direct to Watch feature for Apple Watch. This lets you receive glucose data straight on your wrist without needing your phone nearby. Compatible models include Apple Watch Series 6 through Series 11, the SE (2nd and 3rd generation), and all Apple Watch Ultra models, running watchOS 10 or later.
For caregivers and family members, the built-in Dexcom Share feature lets you send your glucose data to up to 10 followers through the Dexcom Follow app. You control exactly what each follower can see, and followers can customize their own notification settings so they’re alerted when your glucose moves outside a comfortable range. This is especially useful for parents monitoring a child’s levels or partners keeping an eye on overnight readings.
Accuracy
CGM accuracy is typically measured by something called MARD, or mean absolute relative difference, which tells you how closely the sensor’s readings match a lab-grade blood glucose measurement. Lower numbers mean better accuracy. In clinical testing comparing the G7 to the G6 in hospitalized adults, the G7 showed a MARD of 12.5% compared to 15.2% for the G6. In everyday outpatient use, the G7 generally performs with tighter accuracy than those hospital numbers suggest, since critically ill patients present more challenging conditions for any sensor.
Who the G7 Is Designed For
The G7 is FDA-cleared for people with type 1 and type 2 diabetes ages 2 and older. It can be used alongside insulin pumps, and some integrated systems use G7 data to automatically adjust insulin delivery. It’s also used by people who don’t take insulin but want tighter visibility into how food, exercise, and stress affect their glucose levels throughout the day. The real-time trend arrows and historical graphs give you a much richer picture of your glucose patterns than occasional fingerstick checks ever could.