Semaglutide
The GLP-1 receptor agonist behind Ozempic and Wegovy — an FDA-approved drug with large, high-quality human trials for type 2 diabetes and weight management. A useful contrast to the unproven peptides.
Quick take
- What it is: a GLP-1 receptor agonist — a peptide-based prescription medicine, not a research chemical.
- What it is used for: type 2 diabetes and chronic weight management, with cardiovascular benefits shown in trials.
- What we actually know: backed by large randomized controlled trials (the SUSTAIN and STEP programs).
- Status: FDA-approved and available by prescription under brand names Ozempic, Wegovy and Rybelsus.
What it is
Semaglutide is a GLP-1 receptor agonist — a peptide-based medicine modeled on the natural hormone glucagon-like peptide-1 (GLP-1). It is included here as an important reference point: unlike most peptides covered on this site, semaglutide is an FDA-approved, prescription drug with a large, high-quality human evidence base.1
It is sold under the brand names Ozempic and Rybelsus (for type 2 diabetes) and Wegovy (for chronic weight management).
How it works
GLP-1 is a hormone released after eating that stimulates insulin, suppresses glucagon, slows stomach emptying and reduces appetite. Semaglutide mimics GLP-1 but is modified to last much longer in the body, allowing once-weekly injection (or a daily oral form).1 The result is improved blood-sugar control and reduced appetite and food intake.
What the evidence shows
Semaglutide is supported by large randomized controlled trials. The SUSTAIN program studied it for type 2 diabetes, and the STEP program studied it for weight management, with average weight reductions well beyond what older agents achieved.2,3 A cardiovascular outcomes trial also showed reduced risk of major cardiovascular events in people with diabetes and established heart disease.4
This depth of human evidence is exactly what most peptides marketed online lack, which is why semaglutide is a useful contrast.
Dosages reported in the literature
Informational only. Semaglutide is a prescription medicine. The figures below summarize approved dosing for context; they are not a recommendation. Dosing must be set and supervised by a prescriber.
| Use | Route | Reported / approved range |
|---|---|---|
| Type 2 diabetes (Ozempic) | Subcutaneous, weekly | Titrated, commonly up to ~2 mg weekly |
| Weight management (Wegovy) | Subcutaneous, weekly | Titrated up to 2.4 mg weekly |
| Type 2 diabetes (Rybelsus) | Oral, daily | Tablet, titrated per label |
Doses are started low and increased gradually to reduce side effects.
Safety & side effects
The most common side effects are gastrointestinal — nausea, vomiting, diarrhea and constipation — usually worst when starting or increasing the dose. Labeled warnings include a boxed warning about thyroid C-cell tumors seen in rodents, and cautions around pancreatitis, gallbladder disease and use in certain conditions.1 It is a prescription medicine and is not appropriate for everyone.
Legal & regulatory status
Semaglutide is FDA-approved and available by prescription. Note that compounded or “research” semaglutide sold outside the regulated supply chain does not carry the same quality assurances as the approved products, and has been the subject of FDA safety communications.5
References
- U.S. Food and Drug Administration. OZEMPIC (semaglutide) injection, for subcutaneous use — Full Prescribing Information. Initial U.S. Approval 2017. Reference label NDA 209637. Available at accessdata.fda.gov. [accessdata.fda.gov] (source identified; pending manual verification)
- Sorli C, Harashima S-I, Tsoukas GM, Unger J, Karsbøl JD, Hansen T, Bain SC. Efficacy and safety of once-weekly semaglutide monotherapy versus placebo in patients with type 2 diabetes (SUSTAIN 1): a double-blind, randomised, placebo-controlled, parallel-group, multinational, multicentre phase 3a trial. Lancet Diabetes Endocrinol. 2017 Apr;5(4):251-260. [PMID 28110911, doi:10.1016/S2213-8587(17)30013-X]
- Wilding JPH, Batterham RL, Calanna S, Davies M, Van Gaal LF, Lingvay I, McGowan BM, Rosenstock J, Tran MTD, Wadden TA, Wharton S, Yokote K, Zeuthen N, Kushner RF; STEP 1 Study Group. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021 Mar 18;384(11):989-1002. [PMID 33567185, doi:10.1056/NEJMoa2032183]
- Marso SP, Bain SC, Consoli A, Eliaschewitz FG, Jódar E, Leiter LA, Lingvay I, Rosenstock J, Seufert J, Warren ML, Woo V, Hansen O, Holst AG, Pettersson J, Vilsbøll T; SUSTAIN-6 Investigators. Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes. N Engl J Med. 2016 Nov 10;375(19):1834-1844. [PMID 27633186, doi:10.1056/NEJMoa1607141]
- U.S. Food and Drug Administration. FDA alerts health care providers, compounders and patients of dosing errors associated with compounded injectable semaglutide products. July 26, 2024. [fda.gov]