Dexcom makes continuous glucose monitors (CGMs) that track your blood sugar levels around the clock without routine fingerstick tests. The sensors are FDA-cleared for managing diabetes in people aged 2 and older, though Dexcom also offers an over-the-counter option for adults without insulin-dependent diabetes who simply want to understand how food, exercise, and stress affect their glucose.
How the Sensor Works
A Dexcom sensor is a small, flexible filament inserted just under the skin, where it sits in the layer of fluid between your cells called interstitial fluid. Glucose from your bloodstream moves into this fluid, and the sensor measures it continuously. It takes a reading every minute and sends an updated glucose value to your phone or receiver every five minutes via Bluetooth, giving you a near-real-time picture of where your blood sugar is and which direction it’s heading.
This is fundamentally different from a traditional fingerstick meter, which gives you a single snapshot in time. A CGM shows trends: whether you’re rising after a meal, holding steady overnight, or dropping toward a low. That trend information is what makes it so useful for day-to-day decisions about food, activity, and insulin dosing.
Who the G7 Is Designed For
The Dexcom G7 is the company’s current prescription CGM. It’s approved for anyone aged 2 and older with any type of diabetes, including type 1, type 2, gestational diabetes, and diabetes during pregnancy. It’s particularly valuable for people who take insulin, because it provides real-time alerts when glucose is trending too high or too low.
One of its most important safety features is a predictive alert that warns you up to 20 minutes before your glucose is expected to drop into the severely low range (below about 55 mg/dL). For people prone to dangerous lows, especially overnight, that early warning can be the difference between catching a drop and waking up in a crisis. You can also customize high and low alert thresholds to match your personal targets.
The G7 sensor is worn on the back of the upper arm for anyone aged 2 and older. Children between 2 and 6 can also wear it on the upper buttocks. Each sensor lasts 10 days, warms up in about 30 minutes after insertion, and doesn’t require fingerstick calibrations during normal use. The sensor and transmitter are built into a single unit roughly the size of a U.S. quarter coin, about 60% smaller than the previous G6 model.
How It Connects to Insulin Pumps
For many people with type 1 diabetes, the biggest advantage of a Dexcom CGM is its ability to communicate directly with an insulin pump. This creates what’s known as an automated insulin delivery system: the sensor reads your glucose, sends that data to the pump, and the pump’s software automatically adjusts how much insulin you receive throughout the day and night.
The G7 and G6 integrate with several pump systems. The Omnipod 5 receives glucose data directly from the Dexcom transmitter to its wearable pod. The Tandem t:slim X2 with its Control-IQ software uses Dexcom readings to increase, decrease, or suspend insulin delivery based on predicted glucose trends. The CamAPS FX system pairs a Dexcom sensor with compatible pumps through a smartphone app. These combinations move diabetes management closer to an artificial pancreas, reducing the number of manual decisions you need to make each day.
The Stelo: An Over-the-Counter Option
In 2024, Dexcom introduced the Stelo, a CGM available without a prescription. It’s designed for a different audience: adults 18 and older who don’t take insulin. That includes people with type 2 diabetes managed through diet or non-insulin medications, people with prediabetes, and even people without diabetes who want to see how their body responds to different foods and habits.
The Stelo differs from the G7 in several important ways. It does not have real-time high or low glucose alerts, which makes it unsuitable for anyone at risk of dangerous blood sugar swings. Its reading range is narrower, displaying values between 70 and 250 mg/dL and simply showing “below 70” or “above 250” outside that window, compared to the G7’s range of 40 to 400 mg/dL. It also cannot connect to any insulin pump or connected insulin pen.
On the practical side, the Stelo lasts 15 days per sensor instead of the G7’s 10, and you can buy it directly from Dexcom’s website or at pharmacies. For someone trying to understand which meals cause glucose spikes or whether their exercise routine is making a measurable difference, the Stelo provides that visibility without needing a prescription or a diabetes diagnosis.
Sharing Data With Family and Caregivers
Dexcom’s sharing feature lets you send your real-time glucose data to up to 10 people through the Dexcom Follow app. Each follower sees your current reading, your trend arrow, and your glucose graph, and they receive the same alerts you do. This is especially useful for parents monitoring a young child’s blood sugar at school, partners keeping an eye on overnight lows, or adult children watching out for aging parents.
The system works in the other direction too. A single person using the Follow app can monitor data from up to 10 different Dexcom users, which is helpful for school nurses, diabetes educators, or parents with more than one child using a CGM.
What Daily Life With a Dexcom Looks Like
You apply a new sensor every 10 days (or 15 with the Stelo) using a one-button applicator that inserts the filament and attaches the adhesive patch in one motion. Most people wear it on the back of their upper arm, where it’s discreet under a sleeve. After a 30-minute warmup period on the G7, readings start flowing to your smartphone app or an optional standalone receiver.
Throughout the day, you can glance at your phone to see your current glucose and a trend arrow showing whether you’re rising, falling, or stable. The app stores your data and generates reports your healthcare provider can review, including metrics like time spent in your target range, average glucose, and patterns around meals or overnight. There’s no need for routine fingerstick calibrations with the G7 or Stelo, though a fingerstick meter may still be useful if a reading doesn’t match how you feel.
The sensor is water-resistant, so you can shower and swim with it. The adhesive keeps it in place during exercise, though some people use additional adhesive patches if they find the edges lifting before the 10-day wear period is up.