Metformin May Help People With Type 1 Diabetes Use Less Insulin, New Trial Finds

Can Metformin Really Help in Type 1 Diabetes?

Metformin has been the cornerstone of type 2 diabetes treatment for decades, prescribed to hundreds of millions of people worldwide. Its mechanism of action — primarily reducing glucose production in the liver and improving insulin sensitivity in peripheral tissues — has long made researchers wonder whether it could also benefit people with type 1 diabetes, an autoimmune condition where the pancreas produces little or no insulin.

While previous smaller studies explored metformin as an adjunct therapy in type 1 diabetes with mixed results, new clinical trial data suggests the drug may meaningfully reduce the amount of insulin people with type 1 diabetes need to inject. This is significant because excessive insulin use can lead to weight gain, increased risk of hypoglycemia, and higher treatment costs — all of which affect quality of life for patients managing this lifelong condition.

How Does Metformin Work Alongside Insulin Therapy?

In type 1 diabetes, the immune system destroys the insulin-producing beta cells of the pancreas, making external insulin essential for survival. However, many people with type 1 diabetes also develop insulin resistance over time — particularly those who are overweight or have a family history of type 2 diabetes. This means they may need progressively higher insulin doses, a phenomenon sometimes informally called "double diabetes."

Metformin addresses this by working through a different pathway than insulin. It activates an enzyme called AMP-activated protein kinase (AMPK), which helps cells take up glucose more efficiently and signals the liver to produce less glucose. By tackling insulin resistance at its source, metformin could allow the injected insulin to work more effectively, meaning less is needed overall. The drug's established safety profile — it has been in clinical use since the 1950s and is on the WHO's List of Essential Medicines — makes it a particularly attractive option for repurposing.

What Could This Mean for Patients and Healthcare Costs?

The cost of insulin remains a major barrier for people with type 1 diabetes worldwide. In the United States, insulin prices have been a subject of intense public debate, and even with recent price caps, many patients struggle with the financial burden of a medication they cannot live without. Metformin, by contrast, is available as a generic drug costing just pennies per dose in many countries.

If larger confirmatory trials validate these findings, adding metformin to the standard insulin regimen for appropriate type 1 diabetes patients could represent a simple, cost-effective way to improve glycemic control while potentially reducing insulin-related side effects such as weight gain and hypoglycemic episodes. Researchers caution, however, that metformin is not a replacement for insulin in type 1 diabetes — it would serve as a complementary therapy. Patients should not adjust their insulin doses without medical supervision.