ADJUST-T1D extension shows glycemic gains fade after stopping semaglutide

A new analysis published in Diabetes, Obesity and Metabolism found that adults with type 1 diabetes who stopped taking semaglutide saw their blood sugar control decline within 12 weeks, compared with those who had been on placebo throughout the original trial ^[1][2].

The study is an extension of ADJUST-T1D, a trial that tested semaglutide as an add-on to automated insulin delivery systems in adults with type 1 diabetes and obesity ^[1]. In the extension phase, researchers tracked continuous glucose monitor data for 16 people who had been randomized to semaglutide and then discontinued it, and 22 people who had been on placebo and did not start any GLP-1 drug during follow-up ^[1][2].

People who stopped semaglutide saw their time in range, the share of hours spent with blood sugar between 70 and 180 mg/dL, fall by a median of 3.6 percentage points. The placebo group's time in range actually rose by 1.5 percentage points over the same period. After statistical adjustment, that gap was significant ^[1][2].

Glucose variability also worsened more in the group that stopped semaglutide. Their glucose standard deviation rose by 6.0 mg/dL versus 1.2 mg/dL in the placebo group, and their coefficient of variation rose by 3.1 percent versus 1.1 percent, both differences reaching statistical significance ^[1][2]. Time spent above range (over 180 mg/dL) increased more in the group that stopped the drug, but that difference did not hold up after statistical adjustment ^[1][2]. Researchers found no meaningful difference between the two groups in measures of low blood sugar, or hypoglycemia ^[1][2].

The researchers note this pattern fits with what has been seen in other GLP-1 discontinuation studies. A four-week follow-up after stopping tirzepatide in the SURPASS-1 trial found A1C rose by about 0.2 percentage points ^[1]. A broader review of GLP-1 discontinuation studies found A1C increases averaging 0.25 percentage points in people with obesity and 0.65 percentage points in people with type 2 diabetes ^[1]. The STEP 1 extension trial found that cardiometabolic gains from semaglutide, including blood sugar improvements, drifted back toward baseline about a year after people stopped the drug ^[1].

The study authors point out an important limit: this analysis only covers people with type 1 diabetes and obesity who were taking semaglutide specifically for weight management alongside insulin pump therapy. They caution the results may not apply to people using semaglutide for other reasons, such as off-label use for insulin resistance without obesity ^[1].

Why it matters for patients

This is a small study, just 38 people combined, but it adds to a growing pattern showing that the glucose benefits of GLP-1 drugs are not guaranteed to last once someone stops taking them. For people with type 1 diabetes who use semaglutide alongside insulin, the findings suggest that stopping the drug could mean spending more hours outside a healthy blood sugar range and dealing with more day-to-day swings in glucose levels, even without a rise in low blood sugar episodes ^[1][2].

Because type 1 diabetes already requires careful insulin dosing, any shift in glucose stability after stopping a medication is something patients and their care teams may want to watch for using continuous glucose monitors. The study does not say how long these effects last beyond 12 weeks, or whether restarting the drug reverses them ^[1][2].

What happens next

The paper was published August 31, 2026 in Diabetes, Obesity and Metabolism ^[1]. The authors do not give a timeline for further follow-up beyond the 12-week extension window studied here, and it is not yet known whether longer-term data on this specific group will be published ^[1][2].