Tirzepatide

Tirzepatide is a once-weekly injectable peptide that activates two incretin receptors at once: the glucose-dependent insulinotropic polypeptide (GIP) receptor and the glucagon-like peptide-1 (GLP-1) receptor. It is among the most extensively studied metabolic peptides, supported by the large SURPASS (type 2 diabetes) and SURMOUNT (obesity) phase 3 programs. It is marketed by Eli Lilly as Mounjaro (diabetes) and Zepbound (obesity/sleep apnea). In controlled trials it produced larger average reductions in HbA1c and body weight than the GLP-1-only comparator semaglutide 1 mg, with mean weight reductions of roughly 16-22.5% across the 5-15 mg doses over 72 weeks in SURMOUNT-1. Its effects on appetite, satiety, and metabolic function appear to come from combined action in the pancreas, gut, and appetite-regulating regions of the brain. Beyond glucose and weight, tirzepatide has generated positive phase 3 signals in obstructive sleep apnea (SURMOUNT-OSA, FDA-approved December 2024), heart failure with preserved ejection fraction with obesity (SUMMIT), and metabolic dysfunction-associated steatohepatitis (SYNERGY-NASH). It is a regulator-approved prescription medicine in several major markets; any non-prescription or 'research' acquisition raises significant legal, purity, and safety concerns.