Over-the-Counter Glucose Monitors: Who Should Use One?

A few years ago, you needed a prescription to wear a continuous glucose monitor (CGM). Now you can order one online or pick one up at a pharmacy. That’s opened the door for people with type 2 diabetes who don’t use insulin, people with prediabetes, and healthy adults who are simply curious about what their lunch does to their blood sugar.

But “you can buy one” isn’t the same as “you should.” This guide explains what over-the-counter (OTC) CGMs are, how they differ from prescription devices, who benefits most, what they cost, and how to read the numbers without over-reacting to every spike.

This is general information, not medical advice. Talk with your clinician before using glucose data to change medications, diet or exercise in a significant way.

What an over-the-counter CGM is

A CGM is a small sensor worn on the back of your upper arm. A tiny flexible filament sits just under the skin and estimates glucose in the fluid between your cells, which the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) describes as very similar to the glucose level in your blood. The sensor sends readings to a smartphone app, so you can see your levels and trends throughout the day without fingersticks.

The OTC era started recently:

• March 5, 2024: The FDA cleared the Dexcom Stelo as the first over-the-counter CGM, for adults 18 and older who don’t use insulin. That includes people with diabetes who use oral medications and people without diabetes who want to understand how diet and exercise affect their blood sugar.
• June 10, 2024: Abbott announced FDA clearance for 2 OTC systems: Lingo, a consumer wellness product for adults 18 and older, and Libre Rio, designed for adults with type 2 diabetes who don’t use insulin.

An important distinction: these devices pierce the skin. The FDA warned in February 2024 that consumers should not use smartwatches or smart rings that claim to measure blood glucose without piercing the skin. The agency said it has not authorized any such device, and inaccurate readings could lead to dangerous medication errors.

OTC vs. prescription CGMs

The sensor technology is related, but the products are built for different people and different risks.

The FDA was explicit about the biggest gap. Stelo should not be used by people with problematic hypoglycemia, because the system isn’t designed to alert users to that dangerous condition. If you use insulin or sulfonylureas, or you’ve had serious low blood sugar episodes, ask your clinician about a prescription CGM instead.

Key takeaway: OTC CGMs are learning tools for people who aren’t at risk of dangerous lows. If your safety depends on catching a low blood sugar fast, you need a prescription CGM with alarms, not a wellness sensor.

Who might benefit from an OTC CGM

Adults with type 2 diabetes who don’t use insulin. Many people in this group check glucose rarely, if at all. A CGM can show how meals, walks after dinner, stress and sleep affect your numbers, which can make conversations with your care team more productive.

People with prediabetes. According to the CDC, prediabetes means a fasting blood sugar of 100 to 125 mg/dL or an A1C of 5.7% to 6.4%. Seeing your own glucose response to different meals can be motivating while you work on lifestyle changes. A CGM does not diagnose prediabetes or diabetes, though. Diagnosis needs lab tests.

Healthy, curious adults. Some people use a sensor for a few weeks to learn how their body responds to their usual breakfast, late-night snacks or workouts. For this group, the value is mostly educational, and a short trial is usually enough.

Who should be cautious or skip it:

• Anyone who uses insulin or is at risk of problematic hypoglycemia. OTC devices aren’t intended for you.
• People under 18. These products are cleared for adults.
• People with a history of eating disorders. Lingo’s own guidance says to consult a health professional first, since constant food-related data can feed unhealthy patterns.
• People prone to health anxiety. Watching every number can be stressful.
• Anyone hoping to diagnose a condition. OTC CGMs aren’t diagnostic tools.

How to read your CGM data sensibly

The most common mistake with OTC CGMs is treating every rise in glucose as a problem. Glucose is supposed to go up after you eat. What matters more are the overall patterns.

What typical numbers look like. A 2019 multicenter study in the Journal of Clinical Endocrinology & Metabolism tracked healthy, non-diabetic children and adults wearing CGMs for up to 10 days. Participants spent a median of 96% of the time between 70 and 140 mg/dL, with average glucose around 98 to 99 mg/dL in most age groups. They spent about 2% of the time above 140 mg/dL, roughly 30 minutes a day. In other words, brief rises after meals are normal, even in healthy people.

Patterns worth noticing:

• How high and how long. A short rise that returns to your baseline within a couple of hours is normal. Glucose that stays high for long stretches is worth discussing with a clinician.
• Overnight and fasting levels. Waking levels give you a sense of your baseline. The CDC’s fasting thresholds, which apply to lab tests rather than sensor readings, are 99 mg/dL or below for normal and 100 to 125 mg/dL for prediabetes.
• Response to changes. Try a 10- to 15-minute walk after dinner, or pair carbohydrates with protein and fiber, and see whether your curve changes.

Reasons a reading may be off:

• Sensor warm-up and the first day. Readings can be less reliable early in a sensor’s life.
• Pressure on the sensor. Sleeping on the arm can cause falsely low readings, often called compression lows.
• Rapid changes. Because the sensor measures fluid between cells, it can trail behind a fingerstick reading when glucose is changing quickly, such as after a meal or exercise.
• Sensor failures. Not every sensor lasts its full rated wear time. Dexcom notes on its Stelo site that a study found about 78% of sensors lasted the full 15 days.

If a reading doesn’t match how you feel, NIDDK advises checking with a fingerstick test and standard meter.

What OTC CGMs cost

Prices change often and vary by product, so check the manufacturer’s site. At the time of writing, makers list a few pricing models:

• Monthly subscriptions that ship sensors automatically. Dexcom’s Stelo site lists a monthly subscription at $89.
• One-time purchases of 1 or 2 sensors, often with no subscription. Abbott’s Lingo site lists a 2-week plan with 1 sensor at $54.
• App features. Some apps include coaching or extra insights. Check whether any features cost extra.

OTC CGMs are generally not covered by insurance, but some products are marked HSA or FSA eligible. If you have diabetes, ask your clinician and insurer whether you qualify for a covered prescription CGM, which may cost less out of pocket.

Privacy and data: what to check

Your glucose data says a lot about your health and habits. Before you sign up:

• Read the privacy policy. Consumer wellness apps may not be covered by HIPAA the way your doctor’s office is.
• Check what’s shared with partners, such as advertisers or other apps you connect.
• Use strong account security. Turn on two-factor authentication and use a unique password.
• Decide who sees your data. Many apps can export reports. You can share a report with your clinician through your patient portal.

Where to start

If you’re thinking about trying an OTC CGM:

1. Check that you’re eligible. You should be 18 or older, not using insulin, and without a history of problematic low blood sugar.
2. Talk to your clinician if you have diabetes, take diabetes medication or have other health conditions.
3. Set a goal and a time limit. For example: “For 2 weeks, I want to see how my usual breakfasts and evening walks affect my glucose.”
4. Keep a simple log of meals, exercise and sleep alongside the data.
5. Focus on patterns, not single spikes.
6. Share what you learn with your care team, and get lab tests, not sensor data, for any diagnosis.

If you’re comparing wearables more broadly, see our guides to smartwatches vs. fitness trackers and smartwatch ECG accuracy. For how clinics use connected devices, read about telehealth and remote patient monitoring. And if you get bloodwork to follow up, our guide on reading lab results in your patient portal can help.

The bottom line

OTC CGMs give adults who don’t use insulin an easy, no-prescription way to see how daily life affects their glucose. They’re most useful for people with type 2 diabetes not on insulin and for people with prediabetes who want feedback on lifestyle changes. They’re not for insulin users or anyone at risk of dangerous lows, they don’t diagnose diabetes, and noninvasive watches and rings that claim to measure glucose aren’t FDA-authorized. Use a sensor for a defined period, focus on patterns, and bring your findings to your clinician.

This is general information, not medical advice.

Sources

• FDA: FDA clears first over-the-counter continuous glucose monitor — Stelo clearance, intended users, hypoglycemia limitation, 15-day sensor
• Abbott: FDA clearance for 2 new over-the-counter CGM systems — Lingo and Libre Rio clearance and intended users
• FDA: Do not use smartwatches or smart rings to measure blood glucose levels — February 2024 safety communication on noninvasive glucose claims
• NIDDK: Continuous glucose monitoring — How CGMs measure glucose and when to confirm with a fingerstick
• Shah et al., CGM profiles in healthy nondiabetic participants (JCEM 2019), via PMC — Normative CGM data: 96% time in 70 to 140 mg/dL
• CDC: Diabetes testing — Fasting glucose and A1C thresholds for prediabetes and diabetes