What are OTC Glucose Monitors?

This year the FDA approved glucose monitors for over-the-counter (OTC) sale for adults who don’t use insulin. The approval came with the warning that people shouldn’t make medical decisions—like self-medicating or drastically changing diet—based on the device’s info. So, who are OTC glucose monitors intended for, and how should these devices be used?

“If you do not have diabetes, a glucose monitor might be interesting for a couple of days but probably not on an ongoing basis,” says endocrinologist Jacqueline Lonier, MD, who treats adults with type 1 and type 2 diabetes at Columbia’s Naomi Berrie Diabetes Center. “If you are at risk of diabetes, it may be useful to monitor periodically, to learn how glucose responds to different foods and activities.”

Dr. Lonier explains glucose, how these OTC monitors work, and when to speak to a doctor.

What is glucose?

Glucose is a type of sugar and the body’s main energy source.

What is a glucose monitor?

A glucose monitor—officially known as a continuous glucose monitor—is a medical device that tracks blood glucose levels on an ongoing basis.

The device has a tiny sensor that is inserted under the skin. It measures the glucose level in the fluid between the body’s cells, which is called interstitial fluid. A transmitter on top of the skin is attached to the sensor and wirelessly sends the glucose data to a smartphone app or other receiver device.

Can an OTC glucose monitor do everything other continuous glucose monitors can?

No. The continuous glucose monitor approved for over-the-counter sale is not meant for people who use insulin to manage their diabetes. This device does not have the option to set up alarms that would notify the user of dangerously low or high blood glucose levels, and it cannot be integrated with automated insulin delivery systems.

Who needs a glucose monitor?

Continuous glucose monitors are lifesaving devices for people with type 1 diabetes who must take insulin continuously to regulate blood glucose levels and prevent diabetic ketoacidosis. These people use continuous glucose monitors to track their glucose trends and adjust their medication doses.

People with type 1 diabetes may use insulin pumps that are integrated with continuous glucose monitors. These devices are called hybrid closed-loop or automated insulin delivery systems. They’re programmed with algorithms that use the glucose data to make automatic adjustments to insulin delivery for the person using the device.

Why were glucose monitors not available over the counter until recently?

For the health and safety of people who need them. A continuous glucose monitor should be used with guidance from a healthcare professional.

People with diabetes use these devices with the guidance of their diabetes care team to properly interpret the data and make safe adjustments to medications and doses. It may seem straightforward to read number on a screen, but treatment decisions are complex and must be individualized.

Who should use OTC glucose monitors, and who should not?

An OTC glucose monitor may be a good option for people with type 2 diabetes who do not use insulin.

It also may be useful to people at high risk for type 2 diabetes who want to learn more about their blood glucose patterns and how their glucose responds to different foods and activities.The data may also be helpful when meeting with a doctor.

In someone without diabetes and who is not at high risk for diabetes—the general public—there is not much useful information to be gleaned from the sensor data. Glucose will go up after eating carbs, but it will return to baseline very quickly.

What do you want everyone to know about monitoring glucose?

Blood glucose levels fluctuate in response to food intake, exercise, and stress in people with and without diabetes. People without diabetes who use one of these devices should discuss any concerns about their observed glucose levels with their physician.