CGMs for People Without Diabetes, the Evidence, Risks and Safer Alternatives

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Quick take: Over-the-counter continuous glucose monitors (CGMs) are cleared by the FDA for adults who do not use insulin, including people without diabetes. Clearance is not proof of benefit, though. A 2026 JAMA Internal Medicine patient page says there is no good evidence that a CGM improves health or prevents diabetes in people without diabetes. This guide covers what the sensors do, what can go wrong, and when a simple lab test is the better tool.

Medical note: This is general education, not medical advice. If you take insulin or other diabetes medicine, talk to a clinician instead of relying on a consumer sensor. In the US, call 911 for an emergency such as fainting, confusion, or trouble breathing. If food worries feel overwhelming or you have thoughts of harming yourself, call or text 988.

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What a consumer CGM actually measures

NIDDK describes a CGM as a device that estimates your glucose level every few minutes and tracks it over time. A tiny sensor sits under the skin, usually on the belly or arm, held by a sticky patch, and sends readings to an app. The key word is estimates. The CDC notes that glucose in the fluid around your cells can differ from glucose in your blood, which is why people with diabetes sometimes confirm readings with a fingerstick.

The CDC says sensors are replaced every 7 to 14 days, and the FDA says a Stelo sensor can be worn up to 15 days, with the app showing trends every 15 minutes.

What the FDA cleared, and what it did not

On March 5, 2024, the FDA cleared the Dexcom Stelo as the first over-the-counter CGM. The FDA describes it as intended for anyone 18 or older who does not use insulin, including people without diabetes who want to understand how diet and exercise may affect blood sugar. The FDA also said the system is not for people with problematic low blood sugar because it is not designed to alert the user to that condition, and that users should not make medical decisions from the output without talking to a healthcare provider. Study adverse events included local infection, skin irritation, and pain or discomfort.

The FDA's review summary for Abbott's Lingo has the same age and insulin limits. That summary states that Lingo's accuracy was assessed in a study of 150 adults with diabetes. I did not find accuracy data for people without diabetes in these sources, so I will not quote a precision figure for healthy users.

Comparison of lab tests, over-the-counter CGMs, and smartwatch glucose claims

Smartwatches and rings are different. In a February 2024 safety communication, the FDA said it has not authorized, cleared, or approved any smartwatch or smart ring that is intended to measure or estimate blood glucose on its own, and told consumers not to buy or use ones that claim to do so without piercing the skin. A watch that merely displays data from an FDA-authorized sensor is a separate matter. See also our Oura Ring vs WHOOP comparison.

What the evidence says for people without diabetes

Johns Hopkins diabetes researchers said in January 2026 that the evidence is scant and that no major clinical trials have tested whether CGMs help people without diabetes lose weight or improve metabolic health. One researcher noted that health outcomes were not a factor in the FDA's decision. A 2024 narrative review from University College London in Diabetic Medicine found little high-quality evidence on CGM accuracy or usefulness in people not living with diabetes. A University of Gothenburg review reported in August 2026 likewise found no scientific evidence of benefit for health or disease prevention in this group.

On the plus side, the JAMA patient page says some argue that seeing numbers might encourage activity or food changes, and Johns Hopkins says a spike after a bagel could motivate someone, though "it's not a given." A June 2025 conference abstract from the American Diabetes Association described early Stelo users without diabetes (about 15,300 people) who spent an average of 93.5% of the time between 70 and 140 mg/dL during their first 30 days. The authors noted this may relate to self-selection. It is a look back at device users, not a trial of health outcomes.

Where a CGM can go wrong

The same sources list several downsides. These are the ones that come up repeatedly:

  • Misreading normal swings. Johns Hopkins says healthy people likely have regular glucose rises, and tracking too closely can create worry about occasional high readings.
  • Cutting healthy foods. JAMA Internal Medicine warns that trying to avoid spikes may lead people to restrict healthy foods such as fresh fruit or swap them for less healthy options. Johns Hopkins notes that a sausage may raise glucose less than an orange, but that is not necessarily a better trade.
  • Anxiety and disordered eating. The UCL review found evidence that CGM use in people without diabetes could cause anxiety about what is normal and raised concern about eating disorders such as orthorexia.
  • Practical problems. JAMA notes sensors can irritate skin, malfunction, or fall off. The CDC suggests rotating sites and avoiding lotion where the sensor sticks.
  • Tunnel vision. A CGM measures only glucose, not cholesterol, triglycerides, or sodium intake (Johns Hopkins).

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Standard tests come first

If your real question is whether you are at risk for prediabetes or type 2 diabetes, lab tests are the established route. Johns Hopkins epidemiologist Elizabeth Selvin said that if you suspect prediabetes, screening with lab tests such as glucose and A1C is still the best way to understand risk. The CDC and NIDDK list these ranges:

  • A1C: below 5.7% is normal, 5.7% to 6.4% is prediabetes, and 6.5% or above is diabetes.
  • Fasting blood sugar (CDC): 99 mg/dL or below is normal, 100 to 125 is prediabetes, and 126 or above is diabetes.

The CDC recommends A1C testing for people over 45, and for younger people who have overweight and another risk factor. The CDC notes severe anemia and kidney failure can falsely raise or lower A1C, and NIDDK says a positive result without symptoms should be confirmed with a repeat test.

Chart sorting what sources say is known and not yet known about glucose graphs in people without diabetes

If you still want to try one

Treat it as a short experiment. A Johns Hopkins researcher suggested that for someone without diabetes, wearing the sensor once or twice may be enough to learn how foods affect glucose. Practical steps drawn from the sources:

  1. Pick a specific question before you start, such as how a usual breakfast compares with another.
  2. Follow the CDC's tips: clean and dry the site first, and rotate sites.
  3. Look at patterns over days, not single readings, and do not cut out whole food groups based on a graph.
  4. Stop and talk to a clinician if the numbers cause distress or you notice you are avoiding meals or foods out of fear.

Five-question checklist to consider before wearing a continuous glucose monitor

When to talk to a clinician

See a clinician if you have increased thirst, frequent urination, or unexplained weight loss, if diabetes risk factors apply to you, or if readings worry you. Do not start, stop, or change any medicine based on a consumer sensor. A skin reaction that is spreading, painful, or looks infected also needs medical attention. Call 911 for fainting, confusion, or trouble breathing.

Related: our guide to home blood glucose meters and unsafe test strips.

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Frequently asked questions

Do healthy people need a CGM?

The sources I reviewed do not support routine use. JAMA Internal Medicine says there is no good evidence that CGM improves health or prevents diabetes in people without diabetes.

Can a CGM diagnose prediabetes or diabetes?

No. The FDA says users should not make medical decisions from the output without a provider. Diagnosis relies on tests such as A1C, fasting glucose, or a glucose tolerance test.

Is a smartwatch that shows blood sugar the same as a CGM?

No. The FDA says it has not authorized any smartwatch or smart ring that measures or estimates blood glucose on its own, and advises against buying them for that purpose.

Are glucose spikes always bad?

Johns Hopkins says healthy people likely have some spikes regularly, and JAMA says their meaning is uncertain in people without diabetes.

Sources

Reviewed against the linked sources on October 30, 2026. The Gothenburg and UCL reviews were checked through news summaries, not the full papers. This article is an editorial summary and interpretation, not medical advice.

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