Home / Wellness technology

Over-the-counter continuous glucose monitor: what to know first

By the Life in Good Form editors. Updated 2026-10-15.

We research products from makers' specs and health sources; we do not run hands-on tests. Links to Amazon may earn us a commission at no cost to you. How this works.

How a CGM works

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) explains that a CGM estimates your glucose level every few minutes and tracks it over time. It has a tiny sensor inserted under the skin, often on the belly or arm, held by a sticky patch; a transmitter; and software on a phone or receiver. The sensor estimates glucose in the fluid between cells, which NIDDK says is very similar to blood glucose.

For the over-the-counter Stelo, the FDA says each sensor can be worn up to 15 days and the app presents glucose measurements and trends every 15 minutes. Abbott says its Lingo biosensor is worn on the upper arm for 14 days.

Over-the-counter options compared

Stelo details are from the FDA's March 2024 announcement; Lingo and Libre Rio details are from Abbott's June 2024 announcement of FDA clearance.

Who these devices are not for

• People who use insulin. The FDA cleared Stelo for adults who do not use insulin. If you use insulin, talk with your provider about a prescription CGM; NIDDK notes doctors may recommend CGMs for people who need insulin.
• People with problematic hypoglycemia. The FDA says Stelo is not for people with problematic low blood sugar because it is not designed to alert the user to this potentially dangerous condition.
• Anyone under 18. The OTC systems above are for adults 18 and older.

The FDA also says users should not make medical decisions based on Stelo's output without talking to their health care provider.

Avoid no-needle glucose watches and rings

In February 2024 the FDA warned consumers not to buy or use smartwatches or smart rings that claim to measure blood glucose without piercing the skin. It said it has not authorized, cleared or approved any smartwatch or smart ring intended to measure or estimate blood glucose on its own, and that these devices are sold under many brand names, including through online marketplaces.

The FDA explains that inaccurate readings can lead people with diabetes to take the wrong dose of insulin or other glucose-lowering medicines, which can quickly cause dangerously low glucose. A watch that displays data from an authorized CGM is different; the warning is about devices that claim to measure glucose themselves. For general wrist trackers, see our fitness tracker band guide.

Living with a sensor

• Skin. NIDDK says some people get skin redness or irritation from the sticky patches. In the Stelo study the FDA reported local infection, skin irritation and pain or discomfort as adverse events.
• Replacing sensors. NIDDK says disposable sensors are replaced every 7 to 14 days depending on the model; the FDA lists up to 15 days for Stelo.
• Double-checking. NIDDK says you may sometimes need to compare CGM readings with a finger-stick test and a standard meter, for example if you doubt a reading.
• Always on. NIDDK notes CGMs keep recording while you shower, work, exercise or sleep.

Is an OTC CGM worth it for you?

The FDA described the first OTC CGM as a way for people to better understand how diet and exercise may affect blood sugar, and to buy a CGM without a health care provider's involvement. NIDDK says seeing glucose in real time can help people make more informed decisions about food, activity and medicines.

Makers also make wellness claims that go beyond what the FDA said. Treat app coaching as general guidance, not a diagnosis. If you have diabetes or abnormal readings, involve your doctor, and remember NIDDK notes a finger-stick check with a standard meter may sometimes be needed.

What to look for when you buy

Questions people ask

Can I buy a continuous glucose monitor without a prescription?

Yes. The FDA cleared Dexcom's Stelo as the first OTC CGM in March 2024, and Abbott announced OTC clearance for Lingo and Libre Rio in June 2024.

Can I use an OTC CGM if I take insulin?

No. Stelo is cleared for people not using insulin. Ask your provider about a prescription CGM.

Do smartwatches measure blood sugar?

No authorized smartwatch or ring measures glucose without piercing the skin, according to the FDA.

How long does a CGM sensor last?

Stelo sensors up to 15 days; Lingo 14 days. NIDDK says disposable sensors generally last 7 to 14 days.

Are there side effects?

The FDA reported local infection, skin irritation and pain or discomfort in the Stelo study.

Sources

• FDA Clears First Over-the-Counter Continuous Glucose Monitor (fda.gov), U.S. Food and Drug Administration
• Do Not Use Smartwatches or Smart Rings to Measure Blood Glucose Levels: FDA Safety Communication (fda.gov), U.S. Food and Drug Administration
• Continuous Glucose Monitoring (niddk.nih.gov), National Institute of Diabetes and Digestive and Kidney Diseases
• Abbott Receives U.S. FDA Clearance for Two New Over-the-Counter Continuous Glucose Monitoring Systems (abbott.mediaroom.com), Abbott

Sources checked 2026-10-15.