Wegovy vs Zepbound: Which Weight Loss Injection Produces Better Results?

You have been living in Phuket for two years. You have a gym routine, you watch what you eat, and your BMI has barely moved. You have read about Wegovy and Zepbound, you know they work differently from older weight loss pills, and now you want one straight comparison before you walk into a clinic.

That is what this is. One head-to-head trial has now directly compared these two drugs. The results are clear enough to act on, with a few things worth understanding before your consultation.

At Takecare Clinic Phuket, a consultation can help match the right option to your specific health history, which matters more than the headline trial numbers alone.

How Each Drug Works: GLP-1 vs Dual GLP-1 and GIP

Wegovy contains semaglutide. It acts on one receptor in the brain and gut, the GLP-1 receptor, which controls appetite and slows stomach emptying. You feel full sooner and stay full longer.

Zepbound contains tirzepatide. It activates two receptors at once: GLP-1 and GIP. The GIP receptor influences fat storage and appears to enhance the appetite effect of GLP-1. Activating both together produces greater weight loss than activating GLP-1 alone.

Both are given as a weekly injection under the skin. Both start at a low dose and increase gradually over several months toward the maximum tolerated dose.

SURMOUNT-5: What the Head-to-Head Trial Actually Found

SURMOUNT-5 was the first trial to compare these two drugs directly in adults with obesity who did not have type 2 diabetes. Participants received either Zepbound or Wegovy at maximum tolerated dose over 72 weeks.

Zepbound produced an average body weight reduction of approximately 20.2%. Wegovy produced approximately 13.7%. Around 31.6% of people on Zepbound lost 25% or more of their body weight, compared with 16.1% on Wegovy.

Those are real differences. Two things are worth knowing before you treat those numbers as settled. The trial was open-label, meaning participants and researchers knew which drug each person was receiving. It was also funded by Eli Lilly, the manufacturer of Zepbound. Neither fact invalidates the results, but both are part of the evidence picture.

Discontinuation due to adverse events occurred in 6.1% of the Zepbound group and 8.0% of the Wegovy group. The trial was not powered to compare safety outcomes, so this difference should not be taken as a definitive finding.

Where Wegovy Still Has the Edge: Cardiovascular Data

If you have existing heart disease, the comparison changes.

The SELECT trial tested semaglutide in obese adults with established cardiovascular disease but without diabetes. It showed a significant reduction in major cardiovascular events: heart attack, stroke, and cardiovascular death. Wegovy received FDA approval specifically for reducing cardiovascular risk in this patient group based on that data.

Zepbound does not yet have this approval. Cardiovascular outcome trials for tirzepatide are ongoing. For a patient with a history of heart attack or significant coronary artery disease, Wegovy’s cardiovascular data is a genuine clinical differentiator right now.

Zepbound holds an FDA approval for obstructive sleep apnea in adults with obesity. If sleep apnea is part of your picture alongside excess weight, that approval is relevant to your conversation with a physician.

Side Effects: What Both Drugs Share and Where They Differ

The side effect profiles of these two medications overlap heavily. Nausea, vomiting, diarrhea, and constipation are the most common complaints for both. They are most likely during dose escalation, the months-long period when your dose is increasing toward the maintenance level.

Most people find these effects manageable. Eating smaller meals, avoiding high-fat foods, and staying well hydrated all help. In Phuket’s heat, hydration matters more than it would at home.

Both drugs share the same serious contraindications. Neither is appropriate if you have a personal or family history of medullary thyroid carcinoma, a rare thyroid cancer, or a condition called MEN2, which affects multiple hormone-producing glands. Both should be avoided in pregnancy. Pancreatitis, inflammation of the pancreas, is a rare but serious risk with both.

Who Should Not Take Either Medication

Beyond the shared contraindications above, a prescribing physician will review several other factors before writing a prescription.

Severe gastroparesis, a condition where the stomach empties too slowly, is a reason to avoid both. Known hypersensitivity to either active ingredient rules out that drug. GLP-1 receptor agonists can slow the absorption of other medications, which matters if you are managing diabetes, blood pressure, or anticoagulation therapy. Kidney function will also be reviewed, as impaired renal function affects tolerability for both drugs.

This is not a checklist you work through yourself. It is why both Wegovy and Zepbound are prescription-only. A physician reviews your full health history, current medications, and relevant blood tests before prescribing.

Long-Term Use, Stopping, and What Happens After

Clinical evidence is consistent on this: most patients regain a significant portion of lost weight within one year of stopping either drug. Both medications suppress appetite through hormonal pathways. When the drug stops, those pathways return to baseline.

This is relevant for anyone in Phuket planning to use either medication for a defined period, whether you are an expat here for two years or a long-stay visitor. Starting one of these drugs without a plan for what happens when you stop is a conversation worth having before your first injection, not after.

Weight regain after stopping reflects the chronic nature of obesity as a condition. For many patients, long-term use is required to maintain results, similar to how blood pressure medication requires ongoing use to control blood pressure.

Getting a Prescription in Phuket: What the Consultation Looks Like

These medications are prescription-only in Thailand. You cannot walk into a pharmacy and buy either one. You need a medical consultation first, and your prescribing physician needs to assess whether you are a suitable candidate, review your medications, and flag any contraindications.

Takecare Clinic Phuket offers walk-in consultations with an English-speaking doctor who can review your health history, discuss which option fits your situation, and advise on monitoring during dose escalation. No appointment needed.

Availability of specific medications can vary in Thailand, as it does globally. The consultation is also the right time to ask about current stock, realistic costs for ongoing treatment, and what monitoring makes sense for your situation. A prescription refill service is available for patients already established on either medication.

If you want baseline blood work before starting, our health check-up service can provide that alongside your consultation. For patients who are not yet sure whether they are a candidate at all, a consultation is the practical starting point.