Researchers at Karolinska Institutet have created an experimental pill that increases fat burning and improves blood sugar control by activating metabolism in skeletal muscle, rather than reducing hunger like current weight loss medications. The approach represents a fundamentally different strategy for treating type 2 diabetes and obesity, with early human trials showing the treatment was well tolerated in 73 participants.

How Does This New Drug Work Differently From GLP-1 Medications?

The new experimental treatment takes an entirely different approach than popular injectable weight loss drugs like Ozempic and Wegovy, which contain semaglutide, or Mounjaro and Zepbound, which contain tirzepatide. Instead of signaling the brain to reduce hunger, the pill activates metabolism directly inside skeletal muscle cells. This distinction matters because it targets the root cause of weight gain in a new way.

The drug is built around a laboratory-engineered molecule called a beta-2 agonist. Researchers redesigned this compound to activate important signaling pathways in muscle tissue without overstimulating the heart, a problem that has historically limited the use of similar drugs. The treatment is taken as a tablet rather than an injection, which may appeal to people who prefer oral medications.

What Are the Key Advantages Over Current Weight Loss Medications?

The most significant potential benefit is what the drug does not do. Unlike GLP-1 medications, which work by suppressing appetite, the new pill appears to preserve muscle mass while promoting fat loss. This distinction is crucial because muscle tissue plays a vital role in metabolic health, blood sugar regulation, and longevity.

Early research also suggests the treatment avoids several side effects commonly associated with GLP-1 drugs, including appetite suppression, muscle loss, and digestive issues. A Phase I clinical trial involving 48 healthy volunteers and 25 people with type 2 diabetes showed that participants tolerated the treatment well.

"Our results point to a future where we can improve metabolic health without losing muscle mass. Muscles are important in both type 2 diabetes and obesity, and muscle mass is also directly correlated with life expectancy," said Tore Bengtsson, professor at the Department of Molecular Bioscience, Wenner-Gren Institute at Stockholm University.

Tore Bengtsson, Professor at the Department of Molecular Bioscience, Wenner-Gren Institute, Stockholm University

How to Understand the Potential Benefits of Muscle-Focused Weight Loss

• Metabolic Health: By activating metabolism in skeletal muscle, the drug helps lower blood sugar levels and increase fat burning without reducing appetite or causing digestive problems.
• Body Composition: The treatment preserves muscle mass while promoting fat loss, which is important because muscle tissue burns more calories at rest and supports overall physical function.
• Combination Therapy: Because the new drug works through a completely different mechanism than GLP-1 medications, researchers believe it could be used alone or alongside existing weight loss drugs for potentially greater benefit.

The research team, which included scientists from Karolinska Institutet, Stockholm University, Uppsala University, the University of Copenhagen, Monash University, and the University of Queensland, published their findings in the journal Cell in 2025.

"This drug represents a completely new type of treatment and has the potential to be of great importance for patients with type 2 diabetes and obesity. Our substance appears to promote healthy weight loss and, in addition, patients do not have to take injections," explained Shane C. Wright, assistant professor at the Department of Physiology and Pharmacology at Karolinska Institutet.

Shane C. Wright, Assistant Professor at the Department of Physiology and Pharmacology, Karolinska Institutet

What Happens Next in the Development Process?

The next phase of research will involve a larger Phase II clinical trial led by Atrogi AB, the company developing the drug. Researchers hope to determine whether the benefits observed in early studies can be replicated in larger groups of people living with type 2 diabetes or obesity. The funding for this research came from several organizations, including the Swedish Research Council, the Swedish Society for Medical Research, and the Novo Nordisk Foundation.

While the results are promising, it is important to note that this treatment is still experimental and not yet available to patients. The early Phase I trial involved a relatively small group, and larger studies will be needed to confirm safety and effectiveness before the drug could potentially be approved for widespread use. For now, people seeking weight loss treatment should continue working with their healthcare providers to explore currently available options, which include GLP-1 medications, lifestyle changes, and other evidence-based approaches.