The Dexcom G6 is a continuous glucose monitor (CGM) that tracks your blood sugar levels around the clock without fingerstick calibrations. It uses a small sensor inserted just under the skin to measure glucose in the fluid between your cells, sending updated readings to your phone or a dedicated receiver every five minutes. The system is used primarily by people with type 1 or type 2 diabetes who need frequent glucose data to manage insulin dosing and avoid dangerous highs or lows.
How the System Works
The G6 measures glucose in interstitial fluid, the liquid surrounding your cells just beneath the skin. A tiny wire-like sensor tipped with a reactive enzyme sits in this fluid and generates an electrical signal proportional to your glucose level. That signal travels to a small transmitter snapped onto the sensor, which wirelessly relays the data to a display device. You can view your readings on the Dexcom app on a compatible smartphone or on a standalone touchscreen receiver.
Because the sensor reads interstitial fluid rather than blood directly, there’s a slight lag compared to a traditional fingerstick. Readings are most accurate after the sensor has been in place for about 24 hours. In a clinical study of 53 participants ages 7 to 70, the overall accuracy (measured as mean absolute relative difference, or MARD) was 11.0%. During the first 12 hours that number was higher at 13.6%, improving to around 10% after the first day of wear.
What’s in the Box
The Dexcom G6 has three core components:
- Sensor and applicator: A one-time-use device that inserts the sensor wire under your skin with a spring-loaded applicator. Each sensor lasts up to 10 days before it needs to be replaced.
- Transmitter: A small, flat piece that clicks into the sensor housing and sends glucose data wirelessly. Each transmitter lasts about three months.
- Display device: Either the Dexcom G6 app on your smartphone or a dedicated Dexcom receiver. Both show your current glucose number, a trend arrow indicating which direction your levels are heading, and a graph of your readings over the past several hours.
No Fingerstick Calibrations Required
One of the G6’s key selling points is factory calibration. Each sensor ships with a unique code printed on its label. When you enter that code into your display device during setup, the system calibrates itself automatically. Older CGMs required you to prick your finger multiple times a day to keep the sensor accurate, but the G6 eliminated that step entirely.
That said, Dexcom still recommends using a traditional blood glucose meter if your CGM readings don’t match how you feel. If you’re experiencing symptoms of low blood sugar but your G6 shows a normal number, a fingerstick is the safer choice for making treatment decisions.
Sensor Warmup and Wear Time
After you insert a new sensor, the G6 requires a two-hour warmup period before it starts displaying readings. During this window, the sensor is stabilizing in the interstitial fluid and won’t show any data. Once warmup is complete, you’ll receive continuous readings every five minutes for up to 10 days. At the end of that 10-day session, the app or receiver prompts you to replace the sensor.
Alerts That Warn You Before Problems Hit
The G6 offers customizable high and low glucose alerts, but its most notable feature is the Urgent Low Soon alarm. This predictive alert triggers when the system calculates that your glucose will drop to 55 mg/dL or below within the next 20 minutes. It’s enabled by default and can’t be turned off, giving you a window to eat something or take other action before reaching a dangerously low level.
You can also set your own alert thresholds. For example, you might choose to be notified whenever your glucose rises above 250 mg/dL or drops below 70 mg/dL. The system lets you adjust these boundaries and set different alert schedules for daytime and nighttime, so you’re not woken up by less urgent notifications while you sleep.
Sharing Glucose Data With Others
The G6 includes a built-in Share feature that lets up to 10 people follow your glucose levels in real time through the free Dexcom Follow app. Followers see your current reading, trend arrow, and graph on their own phone, whether they’re in the same house or a different country. This is particularly useful for parents monitoring a child with diabetes at school, or for partners who want to be alerted if glucose drops overnight.
You control exactly what each follower can see, and followers can customize their own notification settings so they’re only alerted at thresholds that matter to them.
Insurance and Medicare Coverage
Most major insurance plans cover CGMs, though your out-of-pocket cost varies by plan. Medicare covers the Dexcom G6 if you take insulin or have a documented history of hypoglycemia, and your healthcare provider confirms that you or your caregiver have been trained to use the device as prescribed. The G6 is available through both pharmacies and durable medical equipment suppliers, and which route you use can affect your copay.
G6 Availability and the Transition to G7
Dexcom has announced that the G6 will be manufactured until July 1, 2026. After that date, supplies may still be available through pharmacies and distributors for a limited time, but Dexcom can’t guarantee stock. The company recommends working with your doctor to transition to the Dexcom G7 or G7 15 Day before that deadline to avoid any gap in supplies.
The G7 is smaller, has a shorter warmup period, and combines the sensor and transmitter into a single disposable unit. If you’re just starting on a Dexcom system now, your provider will likely prescribe the G7 directly. If you’re a current G6 user, you have until mid-2026 to make the switch.