Peptide Pulse - April 2026

Eli Lilly's Phase 3 TRIUMPH program for retatrutide (LY3437943) - a triple GIP/GLP-1/glucagon receptor agonist - has completed enrollment across its major obesity cohorts. Phase 2 data published in the NEJM demonstrated a mean body weight reduction of up to 24.2% at 48 weeks, outperforming semaglutide and tirzepatide comparators in head-to-head analyses.

A 2025 preclinical study published in Peptides examined the systemic bioavailability of orally administered BPC-157 in rodent models. The researchers found measurable serum concentrations following oral gavage, with some evidence of mucosal absorption in the stomach - consistent with BPC-157's known gastric origin as a fragment of gastric juice protein.

A pharmacokinetics review of Thymosin Beta-4 fragments, including TB-500 (the synthetic Ac-SDKP fragment), confirms a plasma half-life of approximately 1.2–1.5 hours following subcutaneous injection in preclinical models. However, the authors note that tissue concentrations - particularly in muscle, connective tissue, and bone - appear to remain elevated for significantly longer, supporting a once-weekly injection frequency during loading phases.