The Dexcom Stelo Glucose Biosensor System is the first over-the-counter continuous glucose monitor (CGM) cleared by the FDA. Launched by Dexcom in 2024, it lets adults 18 and older who do not take insulin view their glucose trends on a smartphone without a prescription, primarily for prediabetes, non-insulin type 2 diabetes, and general metabolic wellness.
What “Glucose Biosensor System” Actually Means
A biosensor is any device that uses a biological component to detect a target molecule. In Stelo, a tiny filament coated with the enzyme glucose oxidase sits just beneath your skin. When glucose in your interstitial fluid contacts the enzyme, a controlled electrochemical reaction produces a small electrical current. The sensor circuitry converts that current into a glucose value and sends it wirelessly to the Stelo app every 15 minutes.
Dexcom uses the term “biosensor system” rather than CGM on some labeling to clarify that Stelo is cleared for wellness and chronic metabolic management rather than acute insulin-dosing decisions.
The FDA Story
On March 5, 2024, the FDA cleared Stelo as the first OTC continuous glucose monitor in US history. This was a major milestone because it opened CGM access to the roughly 96 million US adults with prediabetes and the many millions more with type 2 diabetes not on insulin. Before Stelo, CGMs required a prescription and usually an insurance-covered diabetes diagnosis.
How the System Works End to End
- Order online directly from Stelo or an authorized retailer
- Apply the sensor to the back of your upper arm using the one-step applicator
- Pair the sensor with the Stelo app on iOS or Android
- Wait approximately 30 minutes for warm-up
- Receive glucose readings every 15 minutes for up to 15 days
- Tag meals, exercise, sleep, and stress to correlate patterns
- Review daily, weekly, and monthly trends in the app
Technical Specifications
| Feature | Stelo |
|---|---|
| Sensor life | Up to 15 days |
| Warm-up time | ~30 minutes |
| Reading interval | Every 15 minutes |
| Measurement range | 40 to 400 mg/dL |
| Water resistance | Yes (shallow water, 30 min) |
| App required | iOS 15+ or Android 10+ |
| Calibration | None (factory calibrated) |
| Prescription | Not required |
Accuracy and Intended Use
Stelo uses the same sensing technology as the prescription Dexcom G7, which has a MARD of 8.2 percent. Stelo’s own MARD in FDA submission data is approximately 10 percent, a modest difference driven mainly by the longer 15-minute update interval. For tracking trends, post-meal spikes, and time in range, that accuracy is more than sufficient.
Stelo is not intended for use in acute decisions such as treating a hypoglycemic event or dosing rapid-acting insulin. If you take insulin, use a prescription CGM like the Dexcom G7 or FreeStyle Libre 3.
Who Benefits Most
The ideal Stelo user is an adult with prediabetes, type 2 diabetes managed by diet or oral medications, or a metabolic-health enthusiast wanting to see how food and lifestyle affect glucose. Wearing Stelo for one to two months typically identifies the three or four specific habits driving your biggest glucose swings.
Check the symptoms of prediabetes page if you are not sure whether Stelo would add value. Common reasons to try it include rising A1C, a family history of diabetes, or unexplained post-meal fatigue.
What a Typical Week of Data Shows
- Specific foods that spike glucose above 180 mg/dL
- The dampening effect of a 10-minute walk after meals
- Fasting glucose trends overnight and into the morning
- How poor sleep elevates baseline glucose the next day
- The impact of alcohol, stress, and illness
Cost, Availability, and Alternatives
Stelo retails for about $89 for a two-sensor pack (roughly 30 days). Subscription pricing reduces the cost slightly. It is available online direct from Dexcom and at select US pharmacies. Abbott’s Lingo is a competing OTC CGM with similar positioning. For prescription needs, Dexcom G7 and FreeStyle Libre 3 Plus remain the main choices.
The Bottom Line
The Dexcom Stelo Glucose Biosensor System brings medical-grade glucose sensing to millions of adults with prediabetes and non-insulin type 2 diabetes for the first time. It is not a replacement for a prescription CGM if you use insulin, but as a behavior-change and metabolic-awareness tool it is hard to beat. If you have been watching your glucose drift upward, two weeks of Stelo data can change how you eat and move for years to come.
Medical disclaimer: This content is educational and not a substitute for professional medical advice. Consult your healthcare provider before making care decisions based on CGM data.
