What Fully Closed Loop Insulin Systems Could Mean for Type 1 Diabetes Management

If you use an automated insulin pump today, you likely still need to tell it when you're eating or exercising. These systems—called hybrid closed loop—do much of the work automatically, but they still need your input to work best.

Fully closed loop (FCL) systems aim to change that. They would manage insulin delivery entirely on their own, without requiring announcements from you. Researchers and clinicians are now working to make this a reality, but first they needed to agree on what 'fully closed loop' actually means and how to measure success.

A group of experts—including doctors, researchers, and people living with Type 1 diabetes—came together to create a unified definition of what fully closed loop systems should achieve. This matters because multiple new technologies are in development, including systems using artificial intelligence, delivering more than one hormone, or tracking more than one blood marker.

Without a clear standard, it would be hard to compare these different approaches or know which ones truly work better. The new framework provides that benchmark.

The expert group identified three core goals for FCL systems. First, they should keep your blood sugar in a tight, healthy range (70–140 mg/dL) as much of the time as possible. Second, they should prevent dangerous lows. Third, they should reduce the work you do to manage your diabetes and improve your day-to-day quality of life.

The framework sets specific targets depending on how advanced the system is. Basic systems should keep blood sugar in the tight range at least 50% of the time. More advanced systems aim for 70% or higher. The most advanced systems target over 90% of the time, with proven ability to prevent low blood sugars even during exercise—when the risk is highest.

Importantly, the new definition recognizes that success isn't measured by blood sugar alone. Fully closed loop systems must also be shown to improve how people actually feel and function—reducing stress, simplifying daily routines, and making diabetes management less of a burden.

This person-centered approach means that future technologies will need to prove they work well in the real world, not just in controlled studies. That includes demonstrating they're safe and effective during everyday activities like eating and exercise.

Source: Diabetes technology & therapeutics. Evidence type: PubMed indexed literature. Type1Cure is an information and intelligence hub, not a medical advice service. This article summarizes published research and does not provide diagnosis, treatment, or personal medical guidance. Always talk to your own care team before changing anything about your Type 1 diabetes management.