Navigating the benefits and harms of GLP-1 and GLP-1/GIP agonists in obesity.
This review paper examines the benefits and harms of GLP-1 receptor agonists (GLP-1 RAs) and dual GLP-1/GIP agonists in the management of obesity. The authors summarize evidence indicating that these drug classes can facilitate significant short-term weight loss and associated improvements in obesity-related conditions, including type 2 diabetes mellitus, cardiovascular disease, and metabolic dysfunction-associated steatotic liver disease. The paper also catalogues a range of adverse effects: common gastrointestinal issues (nausea, vomiting, acute pancreatitis, dehydration, and malnutrition), reduced efficacy of oral contraceptives, allergic reactions, and rarer events such as thyroid cell tumours and non-arteritic anterior ischaemic optic neuropathy. The authors highlight that up to one-third of weight lost may be lean tissue (muscle and bone), discontinuation rates may reach 80% at two years, and subsequent weight regain can account for up to two-thirds of prior loss—often disproportionately as fatty tissue. The paper recommends that GLP-1 RA therapy be initiated alongside supervised exercise and individualised dietary guidance, with ongoing monitoring for cessation, malnutrition, and inappropriate fat regain. A key limitation is that this is a narrative review and does not present original trial data.
Why this grade: This is a narrative review synthesizing existing literature rather than reporting original human trial data, so it is graded as review-level evidence.
Obesity is becoming increasingly common worldwide. Glucagon-like peptide-1 receptor agonist (GLP-1 RA) type drugs have the potential to help patients achieve considerable weight loss. Several benefits have been described in the short term, especially relating to diseases associated with obesity, where rapid weight loss results in undoubted improvements. These conditions include type 2 diabetes mellitus, cardiovascular disease and metabolic dysfunction-associated steatotic liver disease. Known adverse effects include gastrointestinal (nausea, vomiting, acute pancreatitis, dehydration and malnutrition), reduced efficacy of oral contraceptives and allergic reactions. Rarer adverse effects include thyroid cell tumours and non-arteritic anterior ischaemic optic neuropathy. Up to 33% of the weight lost is lean tissue mass (muscle and bone). Discontinuation rates can be up to 80% after 2 years. Subsequent weight regain can be up to two-thirds of prior weight loss. There is a risk of much of this regain being fatty tissue. To avoid this and associated malnutrition, GLP-1 RAs should only be initiated along with a supervised exercise programme and individualised dietetic advice. Subsequent patient monitoring to detect cessation, malnutrition and inappropriate fatty tissue weight gain is recommended.
Educational summary of published research — not medical advice. Full text is shown only where licensing permits.