Glucagon-like peptide-1 (GLP-1) receptor agonists have become frontline agents in obesity treatment due to their efficacy. However, there is considerable inter-individual variability in treatment response. Although these agents are primarily degraded by proteolytic enzymes rather than cytochrome P450 (CYP) pathways, pharmacogenomic factors may indirectly influence therapeutic outcomes. This review investigates the role of CYP2D6 polymorphisms in optimizing GLP-1 receptor agonist therapy in obesity. It explores genetic influences on treatment variability and highlights the importance of personalized dosing strategies. A systematic search of PubMed, Embase, and Web of Science (1990-2025) was conducted using terms such as "CYP2D6 polymorphisms," "GLP-1 receptor agonists," "pharmacogenomics," and "personalized medicine." Emphasis was placed on primary experimental studies. While GLP-1RAs are not CYP2D6 substrates, pharmacogenomic factors play a key role through indirect mechanisms. ARRB1 (rs140226575 and Thr370Met) and GLP1R (rs6923761 and Gly168Ser) variants affect glycemic response. CYP2D6 polymorphisms significantly influence metabolism of concomitant medications (e.g., antidepressants and beta-blockers), affecting efficacy and safety. Ethnic variability in CYP2D6 allele frequencies further underscores the need for tailored approaches. Integrating pharmacogenomic data, including CYP2D6 status, can support personalized obesity management and improve clinical outcomes. The primary metabolizers of GLP-1 receptor agonists are proteolytic enzymes; nevertheless, pharmacogenomic heterogeneity influences treatment results via both direct and indirect mechanisms. Variants in CYP2D6 polymorphisms have an indirect impact on treatment outcomes through changed metabolism of concurrent drugs including beta-blockers and antidepressants, while variations in GLP1R and ARRB1 directly affect receptor signaling and weight loss effectiveness.
