The most widely prescribed GLP-1 agonist for weight loss and type 2 diabetes.
Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist developed by Novo Nordisk. It works by mimicking the incretin hormone GLP-1, which is naturally released after eating. By activating GLP-1 receptors in the pancreas, brain, and gastrointestinal tract, semaglutide increases insulin secretion, reduces glucagon, slows gastric emptying, and creates a powerful sensation of fullness.
Originally approved for type 2 diabetes (as Ozempic, 2017), semaglutide gained FDA approval for chronic weight management (as Wegovy, 2.4 mg weekly) in 2021. Rybelsus is an oral formulation approved for diabetes. It was the first oral GLP-1 approved in the US. The drug works centrally — affecting appetite centers in the hypothalamus — which distinguishes it from earlier weight-loss interventions.
Compounded semaglutide became widespread during the shortage of branded products (2022–2024). The FDA declared branded semaglutide shortage resolution in early 2024, raising compliance questions for compounding pharmacies. Patients should understand whether they are receiving FDA-approved Ozempic/Wegovy or a compounded version — these are not clinically equivalent.
The STEP clinical trial program (STEP 1-4, 2021) demonstrated 15–17% average body weight reduction over 68 weeks with 2.4 mg weekly semaglutide. The SELECT trial (2023) demonstrated a 20% reduction in major cardiovascular events in people with obesity and established heart disease — a landmark finding that led to a new FDA indication.
The SCALE trial program for the diabetes indication showed robust HbA1c reductions. Semaglutide is among the most thoroughly studied peptides with over 50 registered clinical trials and robust real-world evidence from millions of patient-years of use worldwide.
📚 Key Reference: PMID: 34403163 (STEP 1), PMID: 37633507 (SELECT trial)
Common side effects include nausea, vomiting, diarrhea, and constipation — especially during dose escalation. Rare but serious risks include pancreatitis, gallbladder disease, and potential thyroid C-cell tumors (seen in rodents; human risk unknown). Contraindicated in personal or family history of medullary thyroid carcinoma or MEN-2 syndrome. Hypoglycemia risk is low as monotherapy but increases when combined with insulin or sulfonylureas. Always consult your provider about your full medication list before starting.
Semaglutide is FDA-approved under multiple branded products: Ozempic (diabetes, Novo Nordisk), Wegovy (weight management, Novo Nordisk), and Rybelsus (oral diabetes, Novo Nordisk). Compounded semaglutide was permitted during FDA-declared shortage periods but faces ongoing regulatory scrutiny as the shortage has been resolved. The FDA has warned about illegally marketed semaglutide products.