Glucagon-like peptide-1 (GLP-1) is produced by the gut, and in a glucose-dependent manner stimulates insulin secretion while inhibiting glucagon secretion, reduces appetite and energy intake, and delays gastric emptying. The GLP-1R agonist semaglutide has recently been registered to treat type 2 diabetes. Area covered: This review is of semaglutide in type 2 diabetes, and considers which properties of this GLP-1R agonist, may be responsible for its clinical outcome benefits . Expert opinion: The pharmacokinetics of semaglutide make it ideal for once-weekly dosing. SUSTAIN 6 (Trial to Evaluate Cardiovascular and Other Long-term Outcomes With Semaglutide in Subjects With Type 2 Diabetes) showed that semaglutide 0.5 or 1 mg subcutaneously once-weekly reduced cardiovascular outcomes in subjects with type 2 diabetes and cardiovascular disease or risk, mean age 65 years, baseline HbA1c 8.7% and mean body weight of 92 kg. Although, semaglutide may be a useful drug in this population, it increased retinopathy to a small extent and this needs further investigation. Also, it is not known whether semaglutide will improve cardiovascular outcomes in other populations including those with lower ages, HbA1c values, and body weights similar to those included in the unsuccessful clinical outcome trials with the GLP-1R agonists, lixisenatide and exenatide.