Are SGLT2 inhibitors safe for type 1 diabetes?

SGLT2 inhibitors have transformed care for people with type 2 diabetes. They not only lower blood sugar but also reduce cardiovascular events and slow the progression of kidney disease. Given these successes, many have asked whether the same benefits extend to people with type 1 diabetes (T1D).

The answer is not straightforward. In T1D, SGLT2 inhibitors remain off-label, and the biggest concern is the increased risk of diabetic ketoacidosis (DKA). Still, emerging evidence continues to show potential benefits, especially in select patients.

Glycemic and metabolic effects

Large trials have tested SGLT2 inhibitors in T1D, including DEPICT-1 and 2 (dapagliflozin) and inTandem 1–3 (sotagliflozin). These studies found:

HbA1c reduction of about 0.3–0.4 percent
6–15 percent lower insulin requirements
2–3 kg of weight loss
Less glycemic variability

For patients, these improvements can mean smoother glucose control and modest weight benefit. However, DKA risk was three to four times higher, especially in pump users or in those who reduced insulin doses too quickly. This remains the central safety issue.

Kidney protection: Early clues

One of the most exciting possibilities is kidney protection in T1D, similar to what has been proven in type 2.

In pooled analyses, dapagliflozin slowed progression of albuminuria and preserved eGFR.
Small real-world studies suggest stabilization of kidney function in patients with T1D and microalbuminuria.

The proposed mechanisms include lowering intraglomerular pressure and improving tubuloglomerular feedback. Still, definitive proof is lacking.

A major trial to watch is the SUGARNSALT study, which is evaluating sotagliflozin in T1D with a focus on kidney outcomes. Results are expected in 2028, and the study includes a DKA prevention program.

Continuous ketone monitoring: A safety innovation

The biggest challenge with SGLT2 use in T1D is preventing DKA, which can occur even when glucose is not very high. Detecting this early has been difficult.

Continuous ketone monitoring (CKM) may offer a solution. Like continuous glucose monitors (CGMs), CKMs track beta-hydroxybutyrate in real time and can provide alerts when ketones begin to rise.

Pilot studies suggest CKMs are accurate and help patients adjust behavior, such as taking corrective insulin earlier or holding the SGLT2 drug when needed. Large trials are not yet available, but FDA clearance of the first CKM systems is anticipated in late 2025 or early 2026. Integration with CGMs and insulin pumps may follow.

If proven effective, CKMs could provide the safety net that makes SGLT2 use in T1D more practical.

Current regulatory status and practical use

For now, SGLT2 inhibitors are not FDA-approved for T1D, and the ADA does not recommend their use outside of research.

Still, some endocrinologists prescribe them off-label for carefully selected patients, such as those who:

Are overweight or insulin-resistant
Have early kidney disease with preserved eGFR
Have higher cardiovascular risk

Key safety principles if used off-label

When considered in practice, SGLT2 use in T1D should follow strict precautions:

Start with the lowest dose available
Provide thorough education on ketone testing and sick-day rules
Encourage daily or real-time ketone checks
Stop the medication during illness, fasting, or surgery
Avoid use in underweight patients, restrictive eaters, or anyone with recurrent DKA

The bottom line

SGLT2 inhibitors offer potential benefits for people with type 1 diabetes, particularly in glycemic control and kidney protection. But the increased risk of DKA remains a major barrier.

The development of continuous ketone monitoring may change this landscape within the next year or two. Until then, SGLT2 inhibitors in T1D should remain a specialist-driven decision, reserved for select patients and closely monitored.

For general physicians, the safest path is to defer prescribing decisions to endocrinology specialists and stay current with professional guidance. In July 2025, the American College of Diabetology announced that Diabetology has received a formal taxonomy classification. This milestone highlights the growing recognition of focused diabetes care and helps clarify the role of specialists as the field evolves.

Zehra Haider is an internal medicine physician.