Retatrutide

Retatrutide is an investigational weight-loss medication that targets three hormones at once — GLP-1, GIP, and glucagon — making it the first “triple agonist” in development. In clinical trials, patients taking the highest dose lost an average of over 24% of their body weight in 48 weeks, rivalling the results of bariatric surgery. It is administered as a once-weekly injection and is not yet approved for general use as of 2026.

Retatrutide (LY3437943) is a single peptide with triple agonist activity at the GLP-1, GIP, and glucagon receptors, designed to maximise weight loss through complementary mechanisms: GLP-1 suppresses appetite and delays gastric emptying, GIP enhances insulin sensitivity and lipid buffering, and glucagon increases energy expenditure via hepatic lipolysis and thermogenesis. Phase 2 trial data (NEJM, 2023) demonstrated dose-dependent mean weight reductions of up to 24.2% at 48 weeks in participants with obesity, with a safety profile comparable to selective GLP-1 agonists. Phase 3 TRIUMPH trials are ongoing as of 2026.

Retatrutide represents the next frontier of medical weight loss — Dr. Wang monitors emerging therapies like this to offer patients the most advanced treatment options as they become available.