A new review published in The Lancet outlines how modern incretin-based drugs, including GLP-1 receptor agonists such as semaglutide and tirzepatide, are transforming the management of obesity and type 2 diabetes. The review synthesizes decades of research on these medications and newer multi-receptor agonists, along with emerging oral therapies.
The analysis finds that synthetic GLP-1 medications, initially designed to control blood sugar, now show clinically validated benefits beyond glucose regulation. These drugs provide protection against cardiovascular disease, chronic kidney disease, and metabolic dysfunction-associated steatotic liver disease (MASLD), with improvements noted in both steatosis and fibrosis-related outcomes. The review also highlights research into "next-generation" therapies capable of producing weight loss up to about 24% in clinical trials—a result comparable to some surgical interventions.
Traditionally, type 2 diabetes and obesity were managed separately: diabetes with insulin or metformin, and obesity with lifestyle changes or less effective drugs. Incretin-based therapies changed this by mimicking gut hormones that boost insulin production and suppress appetite. According to the review, “These medications, particularly Glucagon-Like Peptide-1 (GLP-1) receptor agonists such as semaglutide and tirzepatide, have been clinically validated to treat both conditions, triggering metabolic cascades that significantly improve disease outcomes.”
Researchers recognized that people with metabolic diseases often experience multiple complications—such as heart failure, kidney disease, or fatty liver—that single-target drugs did not fully address. Recent efforts have focused on developing new incretin-based medications targeting several metabolic pathways at once.
The review draws from major randomized trials and clinical development programs up through October 2025. It evaluates various drug classes across patient groups including those with established type 2 diabetes, obesity, cardiovascular disease (CVD), or chronic kidney disease (CKD). Rather than conducting a new meta-analysis, the authors synthesize findings from significant randomized clinical trials focusing on glycated hemoglobin levels (HbA1c), body weight reduction, major adverse cardiovascular events (MACE), and kidney function decline.
Safety data are also discussed in the review. It focuses on gastrointestinal side effects and notes emerging concerns like reductions in lean body mass accompanying substantial weight loss.
According to the authors: “The review confirms that incretin-based therapies have not only achieved their intended goal of T2D and obesity management but have also demonstrated clinically meaningful benefits across multiple organ systems.”
In terms of cardiovascular outcomes, the SELECT trial found that semaglutide reduced risk of MACE by 20% among people with obesity but without diabetes; however, several secondary outcomes did not reach statistical significance under hierarchical testing procedures. For kidney health, the FLOW trial showed a 24% reduction in severe kidney outcomes—including kidney failure and death—with semaglutide use.
Newer agents like tirzepatide produced even greater weight loss than semaglutide in head-to-head studies: 20.2% versus 13.7%. In phase 2 trials for retatrutide—a triple agonist—the mean bodyweight reduction reached up to 24.2% over 48 weeks. Oral alternatives such as orforglipron achieved up to an 11.2% weight reduction at 72 weeks.
Beyond weight loss and glycemic control, these drugs are also being studied for their impact on comorbidities. Tirzepatide was shown to significantly reduce sleep apnea severity; based on this evidence “the U.S. Food and Drug Administration has approved obstructive sleep apnea as a new therapeutic indication for tirzepatide.” Both semaglutide and tirzepatide demonstrated potential benefits for MASLD by reducing systemic inflammation and improving liver-related outcomes.
However, individual responses vary widely—patients often regain lost weight if treatment is stopped—highlighting obesity’s chronic nature. The authors write: “The present review elucidates the physiological benefits of synthetic incretin-based medications… highlighting both their unprecedented clinical efficacy against T2D and obesity and their extensive non-target metabolic benefits against heart, kidney, and liver diseases.” They add that advances in triple agonists and oral formulations may further lower barriers to treatment.
Yet challenges remain; significant weight loss can be accompanied by reductions in lean body mass—a concern requiring more research into strategies for preserving muscle during fat loss—and gastrointestinal side effects still need careful management through dose escalation protocols.
