What It Is
Semaglutide is a synthetic analog of glucagon-like peptide-1 (GLP-1), an incretin hormone involved in glucose regulation and appetite.[1] Structural modifications, including a fatty-acid side chain that promotes albumin binding and resistance to enzymatic breakdown, extend its half-life and support once-weekly dosing for approved injectable products.[7]
FDA-approved semaglutide products include Ozempic, Rybelsus, and Wegovy, each with product- and indication-specific labeling.[2][3][4] By 2026, Wegovy labeling included multiple injection presentations, an oral tablet presentation, cardiovascular-risk reduction, and an accelerated-approval indication for specified adults with noncirrhotic MASH and F2–F3 fibrosis; Wegovy HD added a 7.2 mg injection presentation.[3][23][24] None of this makes an unverified research powder equivalent to an approved product.
How It Works
Semaglutide activates GLP-1 receptors involved in glucose-dependent insulin secretion, glucagon regulation, gastric emptying, appetite, and food intake.[8] Hypoglycemia risk rises when semaglutide is combined with insulin or insulin secretagogues; exact risks and instructions vary by product and indication.[2][3][4]
What the Research Shows
Semaglutide has a large human evidence base across diabetes, weight management, and cardiovascular outcomes. STEP 1 found greater mean weight reduction with semaglutide 2.4 mg than placebo over 68 weeks, while SELECT found fewer major adverse cardiovascular events in adults with established cardiovascular disease and overweight or obesity without diabetes.[9][13]
SUSTAIN-6 reported fewer cardiovascular events in people with type 2 diabetes at high cardiovascular risk.[11] Results remain population-, formulation-, and dose-specific, and a randomized withdrawal study found weight regain after semaglutide discontinuation.[22]
Safety & Side Effects
Gastrointestinal adverse effects such as nausea, vomiting, diarrhea, constipation, and abdominal pain are common across semaglutide labels. Current labeling also addresses pancreatitis, gallbladder disease, acute kidney injury due to volume depletion, severe gastrointestinal reactions, and a boxed warning about thyroid C-cell tumors observed in rodents.[2][3][4]
Contraindications, interactions, pregnancy guidance, and administration instructions vary by product. A summary cannot replace the current prescribing information.
Regulatory Status
Semaglutide approval is product-, presentation-, and indication-specific. Current U.S. sources should be checked because labeling changed materially through 2026, including new Wegovy presentations and indications.[2][3][4][23][24] The European Medicines Agency separately authorizes defined products and indications in Europe.[19] Approval does not extend automatically to a different formulation, dose, manufacturer, or off-label population.
Compounded & Grey-Market Semaglutide
FDA has warned about dosing errors with compounded injectable semaglutide and about products using salt forms that differ from the active ingredient in approved products.[5][20] In April 2026, FDA proposed excluding semaglutide, tirzepatide, and liraglutide from the 503B bulks list after finding no clinical need for outsourcing facilities to compound them from bulk substances; the proposal remained subject to the regulatory process described by FDA.[25]
A product marketed as semaglutide is not thereby equivalent to an approved medicine. Compounded drugs are not FDA-approved, and unverified online research vials add separate identity, purity, concentration, sterility, and dosing risks.