As appetite for blockbuster weight-loss drugs grows worldwide, scientists are developing the next crop of medications that, they hope, will improve the performance of these drugs and offer benefits beyond weight loss.

“It’s going to be another year where, every week, there’s going to be something really cool,” says Daniel Drucker, an endocrinologist at the University of Toronto in Canada.

New obesity definition sidelines BMI to focus on health

Drug makers are building on the success of medications such as Ozempic and Wegovy, which contain the active ingredient semaglutide, a glucagon-like peptide-1 (GLP-1) receptor agonist. These drugs mimic the hormone GLP-1, helping to regulate blood-sugar levels and appetite.

But most of these medications are costly, require weekly injections and need to be taken long-term to prevent weight regain. These are some of the issues that companies hope alternative drugs will address.

Nature looks at the weight-loss medicines being tested in 2025 and what they have to offer.

Tirzepatide: cuts heart weight and surrounding fat

Tirzepatide — sold as Mounjaro and Zepbound and given by injection — mimics GLP-1 and another hormone called gastric inhibitory polypeptide (GIP), which is involved in fat metabolism. In trial results published in November, it helped participants to lose up to 20%