Wegovy vs Zepbound: Which GLP-1 Is Right for You?

Wegovy® and Zepbound® are the two FDA-approved medications built specifically for chronic weight management — and for most people choosing between them, it's the single biggest decision in their treatment plan. Both are once-weekly injections. Both suppress appetite. Both have been studied in tens of thousands of patients, including head-to-head. But they're different molecules, made by different manufacturers, produce different amounts of weight loss, and are priced differently.

Here's what the clinical evidence actually shows, side by side.

Quick comparison

Both are FDA-approved, cash-pay through Pallas; not billed to insurance.

How they work

Both medications mimic natural gut hormones released after eating — but Zepbound® mimics two of them, which is why it tends to be more effective.

Wegovy® (semaglutide) is a GLP-1 (glucagon-like peptide-1) receptor agonist. When you eat, your gut releases GLP-1, which signals fullness to your brain, slows stomach emptying, and prompts insulin release. Semaglutide mimics GLP-1 but lasts far longer than the natural hormone — a single weekly injection holds steady levels.

Zepbound® (tirzepatide) is a dual agonist. It activates the same GLP-1 receptor as semaglutide, plus a second receptor called GIP (glucose-dependent insulinotropic polypeptide), another gut hormone involved in fat metabolism and energy balance. Hitting both receptors produces stronger appetite suppression and greater average weight loss.

For a deeper look at the receptor biology behind both, read our explainer on how GLP-1 and GIP work.

Effectiveness: what the trials showed

Each drug has its own pivotal trial, and — unusually — they've also been compared directly.

STEP-1 (Wegovy®, semaglutide 2.4 mg weekly):

• Average weight loss: 14.9% of body weight at 68 weeks
• 50% of participants lost at least 15%
• 32% lost at least 20%

SURMOUNT-1 (Zepbound®, tirzepatide 15 mg weekly):

• Average weight loss: 20.9% of body weight at 72 weeks
• 57% of participants lost at least 20%

SURMOUNT-5 (head-to-head, 2025): In the first direct randomized comparison, participants on tirzepatide 10 mg or 15 mg weekly lost an average of 20.2% of body weight versus 13.7% on semaglutide 1.7 mg or 2.4 mg weekly at 72 weeks — a clear edge for Zepbound® in the same study. That trial capped semaglutide at 2.4 mg, though, and Wegovy®'s maximum dose is now 7.2 mg weekly; in the separate STEP UP trial that dose reached 18.7% at 72 weeks. Separate trials aren't a direct comparison, so read the head-to-head result as applying to the doses SURMOUNT-5 actually studied.

For a 220-lb starting weight, that's roughly 30 lbs on Wegovy® (1.7 mg or 2.4 mg) vs 44 lbs on Zepbound® (10 mg or 15 mg) at the SURMOUNT-5 averages. The weight loss projection calculator will model your specific starting point against either curve. Averages are not guarantees — individual response varies widely, and both are highly effective.

Dosing and titration

Both must start low and increase gradually to minimize side effects — mostly nausea. Titrating too fast is the most common reason people quit in the first month.

Wegovy® titration:

1. Weeks 1–4: 0.25 mg
2. Weeks 5–8: 0.5 mg
3. Weeks 9–12: 1.0 mg
4. Weeks 13–16: 1.7 mg
5. Week 17+: 2.4 mg (maintenance)

Zepbound® titration:

1. Weeks 1–4: 2.5 mg
2. Weeks 5–8: 5 mg
3. Weeks 9–12: 7.5 mg
4. Weeks 13–16: 10 mg
5. Weeks 17–20: 12.5 mg
6. Week 21+: 15 mg (maintenance)

Many patients reach their goal at a lower dose and never need the maximum. Your provider adjusts titration based on how you tolerate each step.

Side effects compared

The profiles are very similar — both share the GLP-1 mechanism. The difference is mostly intensity, since greater weight loss tends to come with greater GI effects.

Most common (both, 20–40% of users in trials):

• Nausea (typically 1–4 weeks after each dose increase)
• Constipation
• Diarrhea
• Vomiting
• Abdominal discomfort

Less common but worth knowing:

• Fatigue (first few weeks)
• Loss of appetite to the point of under-eating (monitor protein)
• Injection-site reactions (minor redness)
• Gallbladder issues (~1–3% of users; risk rises with rapid weight loss)

Rare but serious:

• Pancreatitis
• Severe allergic reactions
• Boxed warning: because of a potential risk of thyroid C-cell tumors, both medications are contraindicated in people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2 (based on animal studies; not conclusively linked in humans)

Most GI side effects resolve within 4–8 weeks of starting or after each titration step. For a deeper look, read our complete guide to GLP-1 side effects.

Cost comparison

Usually the deciding factor for anyone paying out of pocket.

Brand-name pricing (without insurance)

With insurance coverage these can drop to $25–150/month, but weight-loss coverage (non-diabetic indication) is inconsistent. Most commercial plans still don't cover weight-loss GLP-1s, and Medicare is prohibited by law from covering anti-obesity medications. Both manufacturers now run direct self-pay programs that meaningfully lower cash costs at lower doses.

Compounded alternatives

When a licensed clinician determines a brand-name product isn't clinically appropriate for a specific patient, compounded semaglutide and tirzepatide are available through US-licensed compounding pharmacies at lower cost. At Pallas, compounded semaglutide injection is $139 for your first month, then $597 every 12 weeks ($199/mo average). Cancel anytime. Compounded tirzepatide injection is $179 for your first month, then $897 every 12 weeks ($299/mo average). Cancel anytime. All cash-pay, with provider visits, dose adjustments, and shipping included.

Which one should you choose?

There's no universally right answer — but there are patterns.

Zepbound® tends to be the better fit if:

• You have a significant amount of weight to lose (40+ lbs)
• You want the highest average weight loss the evidence supports
• Semaglutide hasn't worked well for you in the past
• A slightly longer titration to maximum dose is fine

Wegovy® tends to be the better fit if:

• Your goal is more moderate (20–30 lbs)
• You want the medication with the longest post-market safety record (approved 2 years earlier)
• You're sensitive to medication effects and prefer fewer titration steps
• Your insurance happens to cover semaglutide but not tirzepatide (or vice versa)

Either works if:

• Your prescriber recommends one based on your health history
• Cost or your specific plan's formulary drives the decision

Ultimately a licensed clinician should make the call with you based on your medical history, goals, and tolerance.

Switching between Wegovy® and Zepbound®

Some patients start on one and move to the other — most often from Wegovy® to Zepbound® after a plateau or a preference for greater average weight loss, though the reverse also happens (cost, insurance formulary, or side-effect tolerance).

A few things to know before asking your provider about a switch:

• It's a clinical decision, not a straight substitution. The two medications aren't interchangeable at "equivalent" doses — there's no dose of Zepbound® that simply replaces a given dose of Wegovy®, since they act on different receptors. Your provider designs a new titration schedule based on your history and tolerance, typically starting Zepbound® at its lowest dose even if you were already at Wegovy®'s maximum.
• Expect your provider to specify timing between stopping one and starting the other, based on your prior dose and how you tolerated it.
• GI side effects can reset. Because Zepbound® activates an additional receptor (GIP) that Wegovy® doesn't, some patients notice a period of nausea or other GI effects similar to when they first started Wegovy®, even after being fully titrated on it.
• Check coverage and cost again. Insurance formularies and cash-pay pricing can differ between the two medications, so it's worth confirming before you switch.

If you're considering it, message your care team — a Pallas provider reviews your history and prescribes the transition plan; this isn't something to do on your own.

References

The trial figures and FDA approvals cited above come from the following primary sources. All efficacy data reflect the FDA-approved branded products at the doses studied and have not been established for compounded preparations.

1. Wilding JPH, Batterham RL, Calanna S, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021;384(11):989–1002.
2. Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med. 2022;387(3):205–216.
3. Aronne LJ, Horn DB, le Roux CW, et al. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (SURMOUNT-5). N Engl J Med. 2025;393(1):26–36.
4. Wharton S, Freitas P, Hjelmesæth J, et al. Once-weekly semaglutide 7·2 mg in adults with obesity (STEP UP). Lancet Diabetes Endocrinol. 2025;13(11):949–963.
5. U.S. Food and Drug Administration. WEGOVY® (semaglutide) prescribing information. 2026.
6. U.S. Food and Drug Administration. ZEPBOUND® (tirzepatide) prescribing information. 2026.

Bottom line: Zepbound® produces more weight loss on average — including head-to-head — while Wegovy® has a longer safety record and a shorter titration. Both are excellent FDA-approved options. The right choice depends on your goals, tolerance, insurance, and your clinician's judgment. It takes about 2 minutes to start the intake.