How They Work Differently
Semaglutide targets a single receptor: GLP-1. Tirzepatide targets two receptors: GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). This dual-agonist mechanism is what sets tirzepatide apart. By activating both pathways simultaneously, tirzepatide provides enhanced appetite suppression, improved insulin sensitivity, and potentially greater metabolic benefits. For a deeper dive into these mechanisms, see our article on how GLP-1 medications work. Think of semaglutide as a focused tool and tirzepatide as a broader one — both are effective, but they take different approaches.
Clinical Trial Results
The SURMOUNT trials for tirzepatide showed average weight loss of up to 22.5% of body weight at the highest dose over 72 weeks. The STEP trials for semaglutide (Wegovy) showed average weight loss of about 15% over 68 weeks. While these numbers come from different trials and direct comparison requires caution, the trend is clear: tirzepatide has consistently shown greater weight loss in clinical research. Both medications significantly outperform older weight loss drugs and lifestyle intervention alone.
Side Effect Profiles
Both medications share similar gastrointestinal side effects — nausea, vomiting, diarrhea, and constipation are common, especially during dose escalation. In clinical trials, tirzepatide's side effect rates were broadly comparable to semaglutide's, with some studies suggesting slightly higher rates of certain GI symptoms at the highest tirzepatide doses. The overall tolerability of both medications is considered acceptable, and side effects typically decrease over time. Read our semaglutide side effects guide for detailed management strategies that apply to both medications.
Cost and Availability
Brand-name versions of both medications are expensive — typically over $1,000 per month at retail price. Semaglutide has been available longer and has more compounded options through telehealth providers, which can significantly reduce cost. Compounded tirzepatide is increasingly available but still less widespread. Insurance coverage varies for both and is often limited for weight loss indications. For a complete pricing breakdown, see our medication cost guide.
What To Know Before Starting GLP-1 Treatment
Before starting GLP-1 treatment, it's important to understand a few key things. These medications require a prescription from a licensed clinician and aren't suitable for everyone. Some people may experience side effects, especially during the first few weeks as the body adjusts.
GLP-1s also tend to work best when combined with basic lifestyle habits like balanced nutrition and regular physical activity.
That's why choosing a provider that offers proper medical screening and ongoing follow-up support is essential for both safety and long-term success.
Dosing Comparison
Semaglutide (Wegovy) titrates from 0.25 mg to a maximum of 2.4 mg weekly over about 16 weeks. Tirzepatide (Mounjaro/Zepbound) starts at 2.5 mg and can go up to 15 mg weekly. Both use gradual dose escalation to minimize side effects. The wider dosing range of tirzepatide gives providers more flexibility in finding the optimal dose. For details on what the first month looks like, see our first month guide.
Can You Switch From Semaglutide to Tirzepatide?
Yes — switching from semaglutide to tirzepatide is common, especially for patients who plateau on semaglutide and want stronger results. Your provider will determine an appropriate starting dose of tirzepatide based on your current semaglutide dose and response. The reverse switch (tirzepatide to semaglutide) also happens, typically for cost reasons since compounded semaglutide is more widely available and less expensive.
Where to Get Either Medication Online
Both medications are available through licensed telehealth providers. Many providers offer both semaglutide and tirzepatide, while some specialize in one. Compare semaglutide providers or tirzepatide providers on our platform. For step-by-step instructions, see our guide on getting GLP-1 medications online.
Which One Is Right for You?
There's no universal answer. Tirzepatide may produce greater weight loss on average, which could be important for patients with more significant weight loss goals. Semaglutide has a longer track record, more real-world data, and broader availability through telehealth providers. Some patients start with semaglutide and transition to tirzepatide if they hit a plateau, while others begin with tirzepatide based on their provider's recommendation. The best choice depends on your health profile, weight loss goals, budget, and provider availability. Take our quiz to find a provider that offers the medication best suited to your needs.