Quick Verdict
Tirzepatide delivers about 6 percentage points more weight loss than semaglutide at maximum doses (20.9% vs 14.9%). Semaglutide has a longer safety record and proven cardiovascular benefits. For most patients focused on weight loss alone, tirzepatide has the stronger clinical data. For patients who also need cardiovascular protection, semaglutide has the edge.
| Feature | Semaglutide | Tirzepatide |
|---|---|---|
| Active Ingredient | Semaglutide | Tirzepatide |
| Drug Class | GLP-1 receptor agonist | Dual GIP/GLP-1 receptor agonist |
| FDA Approved For | Weight loss (Wegovy), Diabetes (Ozempic) | Weight loss (Zepbound), Diabetes (Mounjaro) |
| Average Weight Loss | 14.9% (STEP-1[3], 68 weeks) | 20.9% (SURMOUNT-1[4], 72 weeks, 15mg) |
| Monthly Cost (Brand) | $1,350/mo (Wegovy) | $1,060/mo (Zepbound) |
| Monthly Cost (Compounded) | $199 to $399/mo | $149 to $399/mo |
| Dosing Frequency | Once weekly injection | Once weekly injection |
| Dose Steps | 5 (0.25, 0.5, 1.0, 1.7, 2.4 mg) | 6 (2.5, 5, 7.5, 10, 12.5, 15 mg) |
| Cardiovascular Benefit | Proven (SELECT trial, 20% MACE reduction) | Under investigation (SURPASS-CVOT) |
| Common Side Effects | Nausea, diarrhea, vomiting, constipation | Nausea, diarrhea, vomiting, constipation |
How Do Weight Loss Results Compare Between Semaglutide and Tirzepatide?
Tirzepatide consistently outperforms semaglutide in clinical trials. The SURMOUNT-1 trial showed tirzepatide 15mg produced 20.9% body weight loss over 72 weeks, while STEP-1 showed semaglutide 2.4mg produced 14.9% over 68 weeks. That gap of roughly 6 percentage points translates to about 15 extra pounds lost for a 250-pound starting weight.
The only direct head-to-head trial (SURPASS-2) compared tirzepatide doses against semaglutide 1mg in patients with type 2 diabetes. All three tirzepatide dose groups lost significantly more weight. Patients on 15mg tirzepatide lost an average of 27 pounds compared to 14 pounds on semaglutide 1mg over 40 weeks.
One important caveat: the SURPASS-2 trial used semaglutide at 1mg, not the full 2.4mg weight loss dose. A true head-to-head at maximum approved doses for obesity hasn't been completed. Still, cross-trial comparisons consistently favor tirzepatide across every dose level.
Trial-by-Trial Weight Loss Breakdown
| Trial | Medication / Dose | Weight Loss (%) | Duration |
|---|---|---|---|
| STEP-1 | Semaglutide 2.4mg | 14.9% | 68 weeks |
| SURMOUNT-1 | Tirzepatide 5mg | 15.0% | 72 weeks |
| SURMOUNT-1 | Tirzepatide 10mg | 19.5% | 72 weeks |
| SURMOUNT-1 | Tirzepatide 15mg | 20.9% | 72 weeks |
| SURPASS-2 (T2D) | Semaglutide 1mg | ~5.7% | 40 weeks |
| SURPASS-2 (T2D) | Tirzepatide 15mg | ~11.2% | 40 weeks |
What Are the Side Effects of Each Medication?
Side effect profiles are remarkably similar because both drugs share the GLP-1 mechanism. The most common complaints are gastrointestinal: nausea, diarrhea, vomiting, and constipation. These typically peak during dose titration and fade within 4 to 8 weeks at a stable dose. For a complete cost breakdown, see our best tirzepatide compounding pharmacies.
View data table
| Category | Overall Value Score | Detail |
|---|---|---|
| FormBlends | 92 | From $299/mo, physician-led |
| Hims/Hers | 78 | Consumer brand, varies |
| Ro | 75 | Telehealth platform |
| Calibrate | 70 | Metabolic health focus |
Nausea affects 20 to 44% of semaglutide patients and 24 to 33% of tirzepatide patients in clinical trials. Vomiting is somewhat more common with semaglutide (5 to 24%) than tirzepatide (5 to 12%). Constipation rates are similar for both, running 10 to 24%.
Discontinuation rates due to side effects are nearly identical: about 4 to 7% for both drugs in their respective weight loss trials. Both carry warnings for pancreatitis, gallbladder disease, and thyroid C-cell tumors in animal studies. Neither should be used by patients with personal or family history of medullary thyroid carcinoma or MEN2.
Side-by-Side Side Effect Rates
| Side Effect | Semaglutide | Tirzepatide |
|---|---|---|
| Nausea | 20 to 44% | 24 to 33% |
| Diarrhea | 15 to 30% | 15 to 25% |
| Vomiting | 5 to 24% | 5 to 12% |
| Constipation | 10 to 24% | 10 to 24% |
| Injection Site Reaction | Mild, infrequent | Mild, infrequent |
| Discontinuation Rate | 4 to 7% | 4 to 7% |
How Does Cost Compare Between Brand and Compounded Options?
Brand-name pricing puts both medications out of reach for most patients paying out of pocket. Wegovy (semaglutide) lists at about $1,350 per month. Zepbound (tirzepatide) lists at about $1,060 per month. Insurance coverage is inconsistent and many plans exclude weight loss medications entirely.
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Take the Assessment →Compounded versions offer a dramatically cheaper alternative. Compounded semaglutide typically runs $199 to $399 per month depending on dose and provider. Compounded tirzepatide starts around $149 to $399 per month. These formulations use compounded formulations of the active ingredient prepared by licensed 503B compounding pharmacies.
The FDA has allowed compounding of both semaglutide and tirzepatide during documented shortages. As of early 2026, the regulatory space around compounded GLP-1 medications continues to evolve. FormBlends works exclusively with pharmacies that maintain full cGMP compliance and third-party testing protocols.
Which Medication Has Better Cardiovascular Evidence?
Semaglutide has a clear advantage here. The landmark SELECT trial demonstrated that semaglutide 2.4mg reduced the risk of major adverse cardiovascular events (heart attack, stroke, cardiovascular death) by 20% in patients with obesity and established cardiovascular disease, even without diabetes. This was the first time a weight loss medication showed cardiovascular risk reduction in a dedicated outcomes trial.
Tirzepatide doesn't yet have comparable cardiovascular outcomes data. The SURPASS-CVOT trial is underway but results aren't expected until 2027. Early signals from metabolic data are encouraging, but no hard endpoint data exists yet.
For patients whose primary concern is heart health alongside weight management, semaglutide currently offers a level of cardiovascular evidence that tirzepatide can't match.
Which Should You Choose? A Decision Framework
The right choice depends on your priorities, medical history, and budget. Neither medication is universally better. Here is a practical framework for thinking through the decision with your provider.
Consider semaglutide if: you have cardiovascular disease or high cardiovascular risk, you want the longest-studied GLP-1 option, you prefer the possibility of an oral formulation (Rybelsus for diabetes), or your insurance covers Wegovy but not Zepbound.
Consider tirzepatide if: maximum weight loss is your top priority, you want the strongest clinical weight loss data available, you have type 2 diabetes and want superior A1C reduction, or the cost difference between brand options matters to you.
Consider compounded versions of either if: you're paying out of pocket and need an affordable entry point, you don't have insurance coverage for brand-name GLP-1 medications, or you want to try the medication before committing to brand-name pricing.
Can You Switch From Semaglutide to Tirzepatide?
Switching between the two medications is common in clinical practice and generally straightforward. Most providers will start tirzepatide at a lower dose (typically 2.5mg) regardless of your previous semaglutide dose, then titrate up based on tolerance and response. The transition usually involves little to no gap in treatment.
Reasons patients switch include hitting a weight loss plateau on semaglutide, wanting to try the potentially stronger tirzepatide option, or cost considerations when one becomes more accessible than the other. The reverse switch (tirzepatide to semaglutide) also happens, often when patients want the cardiovascular protection data or when insurance coverage changes.
At FormBlends, our clinical team manages these transitions regularly. We adjust dosing schedules and monitor for any changes in side effects during the switch period.
What Does the Future Look Like for These Medications?
Both molecules are being studied for uses well beyond weight loss. Semaglutide is in trials for metabolic-associated fatty liver disease (MASLD), Alzheimer's disease, addiction, and kidney disease. Tirzepatide has shown strong results for heart failure with preserved ejection fraction and obstructive sleep apnea.
Next-generation molecules are also entering the picture. Retatrutide, a triple-receptor agonist (GLP-1/GIP/glucagon), showed up to 24% weight loss in Phase 2 trials. CagriSema combines semaglutide with the amylin analogue cagrilintide and has demonstrated roughly 22.7% weight loss. These next-wave drugs suggest that the 20 to 25% weight loss range may become standard within a few years.
For now, semaglutide and tirzepatide remain the two most proven and widely available options. Choosing between them is less about picking a winner and more about matching the right molecule to your specific health profile.
Frequently Asked Questions
Is tirzepatide more effective than semaglutide for weight loss?
Yes. Clinical trials show tirzepatide at its highest dose (15mg) produces about 20.9% body weight loss compared to 14.9% for semaglutide at 2.4mg. Even at the lowest tirzepatide dose (5mg), results match full-dose semaglutide.
Which has fewer side effects, semaglutide or tirzepatide?
Side effect profiles are very similar. Both cause GI issues like nausea, diarrhea, and vomiting. Tirzepatide may cause slightly less vomiting than semaglutide at comparable effectiveness levels. Discontinuation rates are nearly identical at 4 to 7%.
How much does semaglutide cost compared to tirzepatide?
Brand-name Wegovy (semaglutide) runs about $1,350/month. Zepbound (tirzepatide) lists at about $1,060/month. Compounded versions of both are available from $149 to $399/month through licensed pharmacies.
Can you switch from semaglutide to tirzepatide?
Yes. Switching is common and safe under medical supervision. Most providers restart tirzepatide at the lowest dose (2.5mg) and titrate up regardless of your previous semaglutide dose.
Does semaglutide have proven heart benefits that tirzepatide doesn't?
Yes. The SELECT trial showed semaglutide reduced major cardiovascular events by 20% in patients with obesity. Tirzepatide's cardiovascular outcomes trial is still ongoing as of early 2026.
Are compounded versions of semaglutide and tirzepatide safe?
Compounded versions from licensed 503B pharmacies that follow FDA cGMP standards are considered safe. Always verify the pharmacy holds proper state and federal registrations before purchasing.
Which is better for someone with type 2 diabetes?
Both are effective for blood sugar control. Tirzepatide showed superior A1C reduction in the SURPASS-2 head-to-head trial. Semaglutide has the advantage of proven cardiovascular risk reduction, which matters for many diabetes patients.
Medical References
- Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. N Engl J Med. 2023;389(24):2221-2232. [PubMed | ClinicalTrials.gov | DOI]
- Frías JP, Davies MJ, Rosenstock J, et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. N Engl J Med. 2021;385(6):503-515. [PubMed | DOI]
- Wilding JPH, Batterham RL, Calanna S, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021;384(11):989-1002. [PubMed | ClinicalTrials.gov | DOI]
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022;387(3):205-216. [PubMed | ClinicalTrials.gov | DOI]