A board-certified internist explains the GLP-1 mechanism, what the landmark STEP 1 trial showed, who qualifies, and what to expect month by month.
By Dr. Teja V. Surapaneni, MD, MS • Board-Certified Internal Medicine (ABIM) • Licensed NV, WA, OR, WI • May 2026
Semaglutide belongs to a class of medications called GLP-1 receptor agonists. GLP-1 stands for glucagon-like peptide-1, a naturally occurring hormone your intestine releases after you eat. When GLP-1 is released, it does several things simultaneously: it signals your pancreas to release insulin (lowering blood sugar), slows the rate at which food leaves your stomach (prolonging the sensation of fullness), and signals the hunger centers in your brain to reduce appetite.
Semaglutide mimics this hormone but with much greater potency and a much longer duration of action. A single weekly injection maintains elevated GLP-1 activity throughout the week, producing a sustained reduction in appetite and caloric intake that patients cannot achieve through willpower alone.
The clinical evidence for semaglutide in weight management is among the strongest ever generated for an obesity medication. In the STEP 1 trial — a landmark Phase 3 study published in the New England Journal of Medicine — adults treated with semaglutide 2.4 mg weekly lost an average of 14.9% of their body weight over 68 weeks, compared to 2.4% in the placebo group.
To put that in practical terms: a 220-pound person would be expected to lose approximately 33 pounds on average. Beyond weight loss, participants saw meaningful improvements in blood pressure, blood sugar, cholesterol, and waist circumference — all major cardiovascular risk factors.
FDA-approved weight management indications for semaglutide include adults with:
Semaglutide is contraindicated in patients with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia type 2 (MEN2). Patients with a history of pancreatitis, severe gastrointestinal disease, or certain other conditions should discuss their full history with their physician.
Semaglutide is initiated at a low dose and titrated upward over several months. This titration period is designed to minimize side effects — primarily nausea, which is the most common complaint — and to give your body time to adjust. Most patients notice reduced appetite within the first few weeks. Weight loss typically accelerates as the dose increases through months 2–5.
Physician check-ins throughout the program allow your provider to optimize your dose and address any side effects. The medication must be used alongside dietary changes for best results; the appetite suppression semaglutide provides makes this significantly more achievable.
Both are weekly injectables in the GLP-1 class, but tirzepatide (Zepbound) adds a second hormone receptor mechanism (GIP) that produces greater average weight loss — approximately 20–22% versus semaglutide’s 14–15%. The right choice depends on your health history, your physician’s assessment, and practical factors like insurance and cost. Our physicians discuss both options during consultation.
Our weight management program includes a physician consultation with a board-certified internal medicine MD, personalized dosing protocol, and ongoing monthly check-ins. We route GLP-1 prescriptions to FDA-approved branded medications through manufacturer pharmacy programs, ensuring authenticity and supply chain integrity.
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Medical disclaimer: This article is for educational purposes only and does not constitute medical advice. Consult a qualified physician before starting any prescription medication. Page medically reviewed by Teja V. Surapaneni, MD, MS — Board-Certified Internal Medicine (NV, WA, OR, WI). Last reviewed: May 2026.