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If you've been researching weight loss medications, you've almost certainly come across two names: semaglutide and tirzepatide. These are the active ingredients behind Ozempic, Wegovy, Mounjaro, and Zepbound — some of the most talked-about medications of the past five years.
Both belong to a class of drugs called GLP-1 receptor agonists, and both have produced weight loss results that would have seemed impossible just a decade ago. But they're not identical. Here's everything you need to know. (For a deeper dive into the biology, check out our guide on how GLP-1 medications actually work.)
How They Work: One Hormone vs. Two
Semaglutide (Ozempic, Wegovy) is a GLP-1 receptor agonist. It mimics a single gut hormone called glucagon-like peptide-1, which signals your brain that you're full, slows digestion, and helps regulate blood sugar. Semaglutide is engineered to last about a week in your body, compared to the natural hormone's two-minute lifespan.
Tirzepatide (Mounjaro, Zepbound) takes things further as a dual GLP-1/GIP receptor agonist — mimicking two gut hormones. The combination amplifies the metabolic effects.
Key difference: Semaglutide targets one hormone pathway (GLP-1). Tirzepatide targets two (GLP-1 + GIP). Both reduce appetite and slow digestion, but the dual mechanism tends to produce more weight loss.
Weight Loss Results From Clinical Trials
| Metric | Semaglutide (Wegovy) | Tirzepatide (Zepbound) |
|---|---|---|
| Trial | STEP trials | SURMOUNT trials |
| Average weight loss | ~15% body weight | ~20–22.5% body weight |
| Duration | 68 weeks | 72 weeks |
| % losing ≥20% | ~33% of participants | ~50%+ at highest dose |
| Example: 230 lb person | ~35 lbs lost | ~46–52 lbs lost |
These are averages. Individual results vary — some people respond better to one than the other. And the benefits go well beyond the scale: emerging research shows GLP-1 medications also protect the heart, kidneys, and liver.
Side Effects Compared
Nausea is the most commonly reported side effect for both, particularly during dose escalation. Other common effects include vomiting, diarrhea, constipation, and decreased appetite. Both use gradual dose-titration to minimize these — you start low and increase slowly.
Serious side effects are rare but can include pancreatitis and gallbladder issues. Both carry a boxed warning about medullary thyroid carcinoma risk from animal studies. Your doctor will review your full medical history before prescribing. For a week-by-week look at what adjustment is really like, see our guide on what to expect your first month on a GLP-1.
Cost and Availability in 2026
| Factor | Semaglutide | Tirzepatide |
|---|---|---|
| Self-pay price | $149–$499/mo (pill vs injectable) | $499–$1,300+/mo |
| Oral option | Yes — Wegovy pill (launched Jan 2026) | Not yet |
| Insurance | Expanding — check your plan | Expanding — check your plan |
| Savings programs | As low as $25/mo with insurance | Zepbound savings card available |
A major development: the Wegovy pill launched in January 2026 starting around $149/month self-pay. No needles, no refrigeration. For a full cost breakdown including savings tips, see our complete GLP-1 pricing guide.
Ready to explore your options? Compare vetted telehealth providers offering GLP-1 prescriptions — with licensed physicians and home delivery.
Compare Top Providers →Dosing Schedules
Semaglutide (injectable): Once-weekly injection, starting at 0.25 mg, titrated over 16–20 weeks to 2.4 mg. The oral pill is taken daily, starting at 1.5 mg up to 25 mg.
Tirzepatide: Once-weekly injection, starting at 2.5 mg, titrated to 5–15 mg maintenance.
Which One Is Right for You?
You might lean toward semaglutide if: you prefer a daily pill over a weekly injection, the lower self-pay price matters, or your insurance covers Wegovy.
You might lean toward tirzepatide if: you want maximum weight loss potential, you've tried semaglutide and plateaued, or your insurance covers Zepbound.
The most important step is talking to a licensed physician. Many telehealth providers offer consultations specifically for GLP-1 prescriptions. And if you're still unsure about these medications overall, our article on 7 myths about weight loss medications separates the facts from the fiction.
Compare the top-rated telehealth platforms for GLP-1 weight loss prescriptions.
Compare Top Providers →Bottom line: Both semaglutide and tirzepatide represent a genuine breakthrough — 15–22% average body weight reduction in clinical trials. The best one for you is the one your doctor recommends based on your unique health picture.