The Dexcom G7 is a continuous glucose monitor (CGM) that tracks your blood sugar in real time through a small sensor worn on your body. It combines the sensor and transmitter into one disposable unit, making setup simpler than older models. Here’s how to get it running, from unboxing to reading your first glucose number.
What’s in the Box
The G7 is a single, integrated unit that contains both the sensor and transmitter. Previous Dexcom models required you to attach a separate transmitter to each new sensor, but the G7 eliminates that step. The whole thing comes pre-loaded inside an auto-applicator, which is roughly the size of a large bottle cap. At 1.1 x 0.9 x 0.2 inches, the on-body sensor is about 60% smaller than the G6.
You’ll also need a compatible smartphone or the optional Dexcom receiver to display your readings. The sensor communicates via Bluetooth, so no additional hardware is required beyond the phone you likely already carry.
Download and Set Up the App First
Before applying the sensor, download the Dexcom G7 app on your phone. You’ll create a Dexcom account (or log in if you already have one), and the app walks you through initial setup step by step. This includes enabling Bluetooth and configuring your phone’s notification settings so alerts come through properly.
If you own an Apple Watch Series 6 or later, you can also use the Direct to Watch feature, which sends glucose data straight to your wrist. This requires watchOS 10 or later, iOS 17 on your paired iPhone, and Dexcom G7 app version 2.2.1 or later.
Where to Place the Sensor
For adults, the approved site is the back of the upper arm. For children ages 2 through 17, both the back of the upper arm and the upper buttocks are cleared options. Kids ages 2 to 6 can also use the upper buttocks exclusively if that’s more practical. The 15-day version of the G7 is currently approved only for adults 18 and older, with placement on the back of the upper arm.
Rotate sides with each new sensor to give your skin a break. Avoid areas where clothing rubs heavily against the adhesive, and steer clear of spots with scar tissue, tattoos, or stretch marks, which can affect readings.
Applying the Sensor
The insertion process takes about a minute once you’ve prepped:
- Wash and dry your hands thoroughly.
- Clean the site with an alcohol wipe and let it air dry completely. Any moisture left on the skin weakens the adhesive.
- Unscrew the cap from the applicator. Don’t touch the inside.
- Place the applicator flat against your skin at the chosen site.
- Press the button. You’ll hear a click. The sensor inserts at a 90-degree angle, straight into the skin. It’s a quick pinch that most people describe as mild.
- Remove the applicator. The adhesive patch and sensor stay behind on your body.
Before you toss the applicator, find the 4-digit pairing code printed on it. You’ll need this in the next step.
Pairing and Warmup
Open the Dexcom G7 app and enter the 4-digit pairing code from the applicator. You can type it in manually or snap a photo. Keep your phone within 20 feet of the sensor during pairing and warmup.
The standard G7 sensor has a 30-minute warmup period before it begins displaying glucose readings. The 15-day version requires a longer 60-minute warmup because it uses a different algorithm to support the extra wear time. During warmup, the sensor is calibrating itself to your body’s interstitial fluid. You won’t see any numbers until this window passes.
One major convenience: the G7 does not require fingerstick calibrations. It’s factory-calibrated, so once warmup finishes, readings appear automatically. You can still enter a fingerstick value if you want to verify accuracy, but it’s not necessary for the sensor to function.
Reading Your Glucose Data
After warmup, your current glucose number and a trend arrow appear on the app’s home screen. The trend arrow shows you the direction and speed your blood sugar is moving, which is often more useful than the number alone. An arrow pointing sharply upward, for example, tells you a spike is happening fast, even if the current number looks acceptable.
The G7 updates your reading every five minutes and stores several hours of data on the sensor itself. If your phone moves out of Bluetooth range temporarily, the sensor keeps recording, and the readings backfill once you’re in range again.
Setting Up Alerts
Customizable alerts are one of the G7’s most practical features. You can configure both high and low glucose alerts with specific thresholds that make sense for your targets. For each alert, you choose the glucose level that triggers it, whether it vibrates or plays a sound, and how long the app waits before reminding you again (the snooze interval).
There’s also an Urgent Low Soon alert that warns you when your glucose is predicted to drop to a dangerous level, giving you time to act before it happens. If you need quiet periods for meetings or sleep, Vibrate Quiet Mode silences all alert sounds and delivers vibrations only.
Wearing It Day to Day
The standard G7 sensor lasts 10 days, plus a 12-hour grace period at the end. The 15-day version extends that to 15 days with the same 12-hour grace window. The grace period keeps your readings going while you prepare a new sensor, so there’s minimal gap in your data.
The sensor is waterproof once inserted. You can shower, bathe, and swim with it on. It’s rated for submersion up to 8 feet deep for as long as 24 hours. That said, your phone won’t receive Bluetooth data through water, so there will be a gap in your app’s display while you’re submerged. The sensor stores those readings and fills them in afterward.
If the adhesive starts peeling at the edges, over-the-counter adhesive patches designed for CGMs can extend the sensor’s hold. Applying a skin barrier wipe before insertion also helps the patch grip longer, especially in humid weather or if you sweat heavily.
Removing and Replacing the Sensor
When your session ends, the app notifies you. To remove the sensor, peel the adhesive patch off like a bandage. If it’s stubbornly stuck, loosen one edge and apply baby oil or an adhesive remover to the exposed skin as you slowly peel it back. Adhesive removal wipes also work well, rubbing the skin just ahead of where you’re pulling.
The sensor contains a tiny, flexible filament that slides out of your skin painlessly. Dispose of the used sensor according to your local guidelines for medical sharps or small electronics. Then open a new applicator and repeat the process on a fresh site.
You can start a new sensor session before the old one fully expires. The app lets you pair the new sensor and begin its warmup while the current sensor is still in its grace period, which keeps the gap between sessions as short as possible.