Semaglutide vs. tirzepatide: a plain-language GLP-1 comparison
Semaglutide and tirzepatide are the two most widely prescribed weekly injections for weight management. They work on overlapping hormone pathways, follow similar dose schedules, and share most side effects — but they are not identical. Here is how they compare, and how a Connect Med provider decides which one fits you.
Side-by-side comparison
| Semaglutide | Tirzepatide | |
|---|---|---|
| How it works | GLP-1 receptor agonist — mimics one gut hormone that slows stomach emptying and reduces appetite. | Dual GIP and GLP-1 receptor agonist — acts on two hormone pathways involved in appetite and blood sugar. |
| Average weight reduction in trials | About 15% of body weight at 68 weeks at the 2.4 mg weekly dose (STEP 1 trial), alongside diet and activity changes. | About 20% of body weight at 72 weeks at the 15 mg weekly dose (SURMOUNT-1 trial), alongside diet and activity changes. |
| How it's taken | Once-weekly subcutaneous injection; oral tablet options also exist. | Once-weekly subcutaneous injection. |
| Dose escalation | Started low and increased gradually over several months to limit nausea. | Started low and increased gradually over several months to limit nausea. |
| Most common side effects | Nausea, constipation, diarrhea, reflux — usually strongest after a dose increase. | Nausea, constipation, diarrhea, reduced appetite — usually strongest after a dose increase. |
| Not appropriate if | Personal or family history of medullary thyroid carcinoma, MEN 2, prior serious reaction to a GLP-1, or pregnancy. | Personal or family history of medullary thyroid carcinoma, MEN 2, prior serious reaction to a GLP-1, or pregnancy. |
Trial figures reference the published STEP 1 (semaglutide 2.4 mg) and SURMOUNT-1 (tirzepatide 15 mg) results. Individual results vary and are not guaranteed.
How your provider chooses
- Medical history. Thyroid cancer history, pancreatitis, gallbladder disease, diabetes, and pregnancy plans all change the recommendation.
- Current medications. Insulin, sulfonylureas, and some oral medications need timing or dose adjustments.
- Side-effect tolerance. If nausea has been a problem before, your provider may escalate more slowly or start with the other option.
- Goals and timeline. Larger targeted reductions and metabolic goals may point toward the dual-pathway option.
- Availability and cost. Supply and pricing differ by formulation, and your provider will review what is realistic to stay on long term.
What a GLP-1 will not do on its own
These medications reduce appetite; they do not replace protein intake, resistance training, or sleep. Losing weight quickly without adequate protein and strength work costs lean muscle, which makes maintenance harder later. Every Connect Med weight program pairs medication with coaching, check-ins, and dose adjustments.
Common questions
- Which one loses more weight?
- In separate clinical trials, tirzepatide produced a larger average reduction in body weight than semaglutide. Averages are not predictions — your response depends on dose tolerance, starting weight, medical history, nutrition, and activity.
- How fast do results show up?
- Most people notice reduced appetite within the first few weeks, while meaningful weight change is typically measured over three to six months as the dose is increased.
- Do I have to stay on it?
- Both medications treat weight as an ongoing condition. Weight regain is common after stopping, so your provider will discuss a long-term plan, including maintenance dosing or a taper.
- What happens if side effects are hard to tolerate?
- Your care team can slow the escalation schedule, hold a dose, or switch medications. Message your provider rather than stopping on your own.
See which option you qualify for
Complete a short medical intake and a U.S. licensed provider will review your history and recommend a plan — or explain why a GLP-1 isn't appropriate for you.
This page is general health information, not medical advice, and does not create a patient-provider relationship. Prescription decisions are made by a licensed clinician after review of your medical history. Seek emergency care for severe abdominal pain, persistent vomiting, or signs of an allergic reaction.