Semaglutide has become one of the most widely used medications for weight management. Originally developed for type 2 diabetes, it is now well established for weight loss as well. Here is a clear look at how it works, what the evidence shows, and what to know about safety.
What is semaglutide?
Semaglutide is a GLP-1 (glucagon-like peptide-1) receptor agonist. GLP-1 is a natural gut hormone that helps regulate appetite, insulin, and blood sugar. Semaglutide mimics that hormone but is engineered to last far longer, which allows once-weekly dosing.
How it works
- Appetite suppression. Semaglutide activates GLP-1 receptors in the brain regions that govern hunger and fullness, so you feel satisfied with less food.
- Slower gastric emptying. It slows how quickly the stomach empties, prolonging fullness after meals and reducing overall intake.
- Glucose-dependent insulin release. It prompts insulin release when blood sugar is high, improving glycemic control, which is especially relevant in type 2 diabetes.
- Reduced glucagon. It lowers glucagon, the hormone that raises blood sugar, helping keep levels stable.
What the evidence shows
In the STEP-1 trial, adults with obesity or overweight lost an average of 14.9% of their body weight over 68 weeks on semaglutide 2.4 mg, compared with 2.4% on placebo.[1] In SURMOUNT-5, the first head-to-head trial against tirzepatide, semaglutide produced an average 13.7% reduction versus 20.2% for tirzepatide over 72 weeks.[2] Both are effective; the difference matters when choosing between them, which our guide on semaglutide vs. tirzepatide covers.
Pharmacokinetics in brief
Semaglutide is given as a subcutaneous injection and has a long half-life of about one week, which supports once-weekly dosing and steady blood levels. It is metabolized slowly and cleared over time, contributing to its prolonged, consistent effect.
Safety and side effects
- Common: nausea, vomiting, diarrhea, and constipation, most often during dose increases and usually easing as the body adjusts.
- Less common but serious: pancreatitis and gallbladder problems can occur; report severe or persistent abdominal pain to your clinician.
- Contraindications: semaglutide is not recommended for people with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2.
Review the full semaglutide safety information and share your complete medical history with your clinician before starting.
Using semaglutide well
Semaglutide works best alongside sustainable changes to diet and activity, and with clinician oversight to manage side effects and adjust your dose. At IVUSE+, compounded semaglutide is prescribed and managed through async telehealth by licensed clinicians.
References
- Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP-1). New England Journal of Medicine. 2021;384:989-1002.
- Aronne LJ, et al. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (SURMOUNT-5). New England Journal of Medicine. 2025;392:2225-2237.
This article is for general education and is not medical advice. Compounded medications are not FDA-approved. A telehealth consultation with a licensed clinician is required before any prescription is issued.
