Recommended Free Tools
A smartwatch that claims to measure glucose by itself is not a continuous glucose monitor (CGM). A CGM uses a wearable sensor to measure glucose continuously or frequently; a compatible smartwatch can display the sensor’s readings, but it does not measure glucose. The U.S. Food and Drug Administration (FDA) warns consumers not to use watches or rings that claim to measure glucose independently.
What measures the glucose?
A CGM measures glucose using a wearable sensor. FDA descriptions define these systems as automatically measuring glucose in bodily fluids continuously or frequently, with readings that can be transmitted securely to digitally connected devices. The precise intended use varies by device and classification.
As an Amazon Associate I earn from qualifying purchases.
A standalone watch claim is different: the watch purports to measure or estimate glucose without relying on an authorized glucose-measuring device. The FDA says it has not authorized, cleared, or approved any smartwatch or smart ring intended to measure or estimate blood glucose on its own. This warning concerns independent glucose measurement; it does not mean every smartwatch health feature lacks authorization.
Free tools Windows power users keep installed
One-click scans. No signup required.
Sources: FDA classification for integrated CGM systems, FDA classification for over-the-counter integrated CGMs, and the FDA safety communication.
#1 Best Overall
- HSA/FSA eligible. No prescription needed.
- 24/7 GLUCOSE TRACKING. See your glucose response to food, exercise, sleep, and other lifestyle factors via the Lingo app.
- OPTIMIZE YOUR NUTRITION. Discover which foods work for you and those that don't. The Lingo app shows you how specific meals and other factors impact your glucose, so you can learn from your insights and build healthier habits
- NAVIGATE PREDIABETES WITH A NEW VIEW OF YOU. More time in healthy glucose range is linked to lower diabetes risk. Three out of four users with prediabetes say Lingo was effective in helping to achieve their health goals¹.
- HEALTHY GLUCOSE SUPPORTS HEART HEALTH. What you eat matters to your glucose and your heart. Keeping your glucose in a healthy range (70–140 mg/dL) more often can help protect your heart from heart disease²⁻⁴.
How do the readings reach a watch?
Some CGM systems can send sensor readings to a compatible phone, receiver, or smartwatch. In that setup, the CGM sensor is still doing the measuring; the watch is a display. The FDA’s review of the Dexcom G7 describes a wearable sensor and transmitter, with a mobile app or receiver as display options, and an optional Direct to Watch feature for users with a compatible iPhone and Apple Watch. The watch app receives data from the sensor—it is not the glucose sensor.
Compatibility is specific to the CGM system and feature. Check the manufacturer’s current instructions for supported phone and watch models, operating systems, region, and setup requirements; support for one system does not establish compatibility for another.
Rank #2
- HSA/FSA eligible. No prescription needed.
- 24/7 GLUCOSE TRACKING. See your glucose response to food, exercise, sleep, and other lifestyle factors via the Lingo app.
- OPTIMIZE YOUR NUTRITION. Discover which foods work for you and those that don't. The Lingo app shows you how specific meals and other factors impact your glucose, so you can learn from your insights and build healthier habits.
- NAVIGATE PREDIABETES WITH A NEW VIEW OF YOU. More time in healthy glucose range is linked to lower diabetes risk. Three out of four users with prediabetes say Lingo was effective in helping to achieve their health goals¹.
- HEALTHY GLUCOSE SUPPORTS HEART HEALTH. What you eat matters to your glucose and your heart. Keeping your glucose in a healthy range (70–140 mg/dL) more often can help protect your heart from heart disease²⁻⁴.
Source: FDA review document for the Dexcom G7 CGM system.
How does a CGM compare with a blood glucose meter?
A blood glucose meter is another way to measure glucose, but it provides a spot check rather than the continuous or frequent readings of a CGM. FDA consumer guidance describes a meter-and-strip system: a handheld meter reads a test strip used with a small blood sample.
Rank #3
- ✅ For people NOT using insulin, ages 18 years and older
- ❌ Don't use if: On insulin, on dialysis, if you have problematic hypoglycemia, are modifying medication without HCP consultation, or if you have a history of eating disorders
- YOUR SUCCESS, OUR COMMITMENT: Should you experience an issue with your biosensor [2] before its 15-day wear time is up, we’ll replace it for free. [3]
- POWERFUL FEATURES: Get AI-powered coaching, plus discover in-app nutrition & glucose insights, advanced meal and activity logging, trend summaries and deep dives, pattern insights and much more—plus, effortlessly sync your data with Apple Health, Google Health Connect, and Oura.
- PRODUCT SUPPORT: Provided by Stelo through SteloBot, which can be accessed via the Stelo app by going to Settings > Contact. SteloBot virtual support assistant is available 24/7, and live agent support is available during regular business hours.
| Method | What measures glucose | How readings are obtained | What a smartwatch does |
|---|---|---|---|
| Standalone watch claim | The watch is claimed to measure or estimate glucose on its own; the FDA says it has not authorized, cleared, or approved such a watch for that purpose. | Not an FDA-authorized glucose-measuring method under the FDA safety communication. | Purports to measure; it is not displaying readings from a CGM sensor. |
| CGM | A wearable glucose sensor. | Continuous or frequent measurements, with readings that may be transmitted to connected devices. | May display readings or alerts if the system supports a compatible watch feature. |
| Blood glucose meter | A handheld meter and test strip used with a small blood sample. | Intermittent, individual tests. | No watch measurement is implied by using a meter. |
Sources: FDA guidance on blood glucose monitoring devices and FDA CGM classification information.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why the distinction matters for safety
The FDA warns that inaccurate glucose readings can lead to diabetes-management errors, including incorrect doses of insulin or other medicines that can rapidly lower glucose. Its February 21, 2024 safety communication advises consumers not to buy or use smartwatches or rings that claim to measure glucose independently, regardless of brand.
Rank #4
- The information below is per-pack only
- HSA/FSA eligible. No prescription needed.
- 24/7 GLUCOSE TRACKING. See your glucose response to food, exercise, sleep, and other lifestyle factors via the Lingo app.
- OPTIMIZE YOUR NUTRITION. Discover which foods work for you and those that don't. The Lingo app shows you how specific meals and other factors impact your glucose, so you can learn from your insights and build healthier habits
- NAVIGATE PREDIABETES WITH A NEW VIEW OF YOU. More time in healthy glucose range is linked to lower diabetes risk. Three out of four users with prediabetes say Lingo was effective in helping to achieve their health goals¹.
For glucose readings used in care decisions, use an appropriate FDA-authorized glucose-measuring device and follow your healthcare provider’s guidance. A watch app does not make a CGM compatible unless the manufacturer supports that combination and feature.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Source: FDA safety communication on smartwatches and smart rings.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
