Triple agonist of the GIP, GLP-1, and glucagon receptors (investigational incretin/metabolic peptide)

Retatrutide

Investigationalaka LY3437943

Retatrutide is a single-molecule 'triple agonist' studied for chronic weight management and type 2 diabetes. In a published Phase 2 obesity trial it produced large dose-dependent weight reductions, and Phase 3 (TRIUMPH) trials are ongoing, with the first positive topline readout reported in late 2025. It remains experimental and is not authorized for clinical use.

Compare

Mechanism

In plain terms, retatrutide mimics several natural gut and pancreatic hormones at once to reduce appetite and food intake while affecting how the body handles glucose and energy. Technically, it is a synthetic peptide that simultaneously agonizes the glucose-dependent insulinotropic polypeptide (GIP) receptor, the glucagon-like peptide-1 (GLP-1) receptor, and the glucagon receptor. GLP-1 and GIP activity promote satiety and glucose-dependent insulin secretion, while glucagon-receptor agonism is thought to increase energy expenditure and lipid metabolism, a combination proposed to drive greater weight loss than single- or dual-incretin agents.

Regulatory Status by Region

  • United States (FDA)Investigational; not approved. Phase 3 TRIUMPH program ongoing, with a first positive topline readout (TRIUMPH-4) reported in December 2025.
  • Australia (TGA)Not entered on the Australian Register of Therapeutic Goods (ARTG); investigational only and not approved for supply.
  • European Union (EMA)Not authorized; investigational, no marketing authorization.
  • WADANot listed on the WADA Prohibited List. As an investigational incretin-class agent it is not a banned substance; the closely related approved GLP-1 agonists are on WADA's monitoring program rather than prohibited.

See the full regulatory status matrix

Key Studies

Related Clinical Trials

Related News & Research

Latest research

See all recent Retatrutide research

Common Questions

What is Retatrutide?
Retatrutide is an investigational once-weekly injectable peptide from Eli Lilly that activates three metabolic hormone receptors (GIP, GLP-1, and glucagon). It is not approved by any regulator as of 2026; it is being evaluated in the Phase 3 TRIUMPH program for obesity, type 2 diabetes, and related conditions.
Is Retatrutide approved for medical use?
Retatrutide is investigational: it is being studied in clinical research and is not an approved medicine. United States (FDA): Investigational; not approved. Phase 3 TRIUMPH program ongoing, with a first positive topline readout (TRIUMPH-4) reported in December 2025. European Union (EMA): Not authorized; investigational, no marketing authorization. Australia (TGA): Not entered on the Australian Register of Therapeutic Goods (ARTG); investigational only and not approved for supply.
How does Retatrutide work?
In plain terms, retatrutide mimics several natural gut and pancreatic hormones at once to reduce appetite and food intake while affecting how the body handles glucose and energy. Technically, it is a synthetic peptide that simultaneously agonizes the glucose-dependent insulinotropic polypeptide (GIP) receptor, the glucagon-like peptide-1 (GLP-1) receptor, and the glucagon receptor.
Is Retatrutide legal in Australia?
Retatrutide in Australia (TGA): Not entered on the Australian Register of Therapeutic Goods (ARTG); investigational only and not approved for supply.
Is Retatrutide banned in sport?
Retatrutide under the World Anti-Doping Agency (WADA) code: Not listed on the WADA Prohibited List. As an investigational incretin-class agent it is not a banned substance; the closely related approved GLP-1 agonists are on WADA's monitoring program rather than prohibited.