Emerging preclinical and observational evidence positions semaglutide and tirzepatide — GLP-1 and dual GIP/GLP-1 receptor agonists — as multi-system modulators extending far beyond glucose control. Antitumor activity appears mediated by immune and metabolic reprogramming rather than direct cytotoxicity, with signals in pancreatic, thyroid, breast, and colorectal cancers. In psychiatry, mesolimbic dopamine pathway modulation and GABAergic effects reduce alcohol use disorder and binge-eating behaviors. Reproductive benefits include improved polycystic ovary syndrome outcomes and male fertility markers, while knee osteoarthritis pain shows clinically meaningful improvement.
This review arrives at a pivotal moment: GLP-1 agonists have already reshaped cardiovascular and metabolic medicine, and the field is now mapping their second-order biology. The mechanisms flagged here — particularly immune reprogramming in oncology and reward-circuit modulation in addiction — are mechanistically plausible and align with independent neuroscience and immunometabolism literatures. However, the authors correctly flag a critical evidentiary gap: nearly all findings derive from animal models, observational cohorts, or pharmacoepidemiologic data. No domain yet has adequate randomized controlled trial evidence. For adults currently prescribed these agents, incidental benefits in mood, addictive behavior, or joint pain may be real — but periconception safety concerns are unresolved and warrant caution. This is a well-framed roadmap paper, confirmatory rather than paradigm-shifting, but clinically valuable for identifying which trials to prioritize next.
