In 2024, continuous glucose monitoring devices hit the shelves for over-the-counter consumer use. Historically, these devices were prescribed for people with type 1 diabetes and, more recently, for those with type 2 diabetes to monitor their glucose levels and adjust insulin dosage. Now, the devices are generating interest in people with prediabetes, obesity, or other conditions, including otherwise healthy people with an interest in wellness. As health tech becomes more common and users gather more data, a Yale-led research team asked: Are continuous glucose monitors helpful for everyone, or just people with diabetes?

A JAMA Internal Medicine paper by Kasia Lipska, MD, MHS, and colleagues reviewed studies evaluating the use of continuous glucose monitoring devices by people other than those with type 1 diabetes.

“There has been an increased interest in monitoring biometrics, glucose levels included,” says Lipska, associate professor of medicine (endocrinology and metabolism). “The assumption seems to be that more information can make us healthy, but we wanted to take a closer look at the research.”

For those who have type 1 diabetes, insulin injections must be administered to allow glucose to be used for energy and prevent it from building up in the bloodstream, where it can cause life-threatening complications. Continuous glucose monitors are placed on the skin and measure glucose levels in the fluid between cells, a level similar to that in the blood, greatly reducing the need for finger-stick testing. For most devices, data is readable in real-time on a mobile phone.

Researchers reviewed pooled analyses of randomized trials published over the past 15 years, investigating whether immediate access to viewing glucose levels improved glycemic control and other patient-reported outcomes for users with type 2 diabetes, prediabetes, overweight, or obesity.

Continuous glucose monitoring devices were most beneficial for those with type 2 diabetes, as they can provide better insight into glucose patterns, including hypoglycemia, and guide medication adjustments, according to the research team. Individuals with type 2 diabetes using the monitors also saw a modest improvement in their hemoglobin A1c levels, which estimate average glucose levels in the bloodstream. These devices can also enable care to be conducted virtually if they are connected to the clinic, adds Lipska.

“I was impressed at the consistency of the positive impact on hemoglobin A1c levels for those with type 2 diabetes,” says Justin Dower, MD, clinical fellow (endocrinology and metabolism), and first author of the paper. “It suggests these devices can be powerful feedback tools about the effects of food, medicine, or exercise on a person’s blood sugar.”

Despite the benefits, researchers also found that continuous glucose monitoring can overload users with data and contribute to anxiety. “It’s easy to get caught up in such tangible data and want to flatten glucose spikes,” says Lipska. Rather than using the feedback to drive behavioral changes, Lipska and the research team note these devices are intended to gather information to discuss with your clinician. “They’re a tool, not a taskmaster,” states Lipska.

Lipska cautions that there is still little to no research on the meaning of glucose spikes in people without diabetes. “If you have diabetes and are taking insulin or other medications, clinicians can adjust dosages based on that data,” says Lipska. “For everyone else, however, there are currently no evidence-based recommendations.”

Because there is currently no evidence that continuous glucose monitoring benefits people without diabetes, Lipska does not recommend its routine use in this population. “Of course, there may be unusual circumstances in which it is worth discussing with a doctor,” she adds.