Tirzepatide vs Semaglutide 2026

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At a glance

	Semaglutide	Tirzepatide
Drug class	GLP-1 receptor agonist	Dual GIP + GLP-1 agonist
Brand names	Ozempic® (diabetes), Wegovy® (weight)	Mounjaro® (diabetes), Zepbound® (weight)
Avg. weight loss (branded, in trials)	~14.9% (STEP-1, 68 wk)	~20.9% at max dose (SURMOUNT-1, 72 wk)
Head-to-head (SURMOUNT-5, 72 wk)	~13.7%	~20.2%
Dosing	Once weekly; max 2.4 mg (Wegovy®)	Once weekly; max 15 mg (Zepbound®)
Common side effects	Nausea ~44% (label)	Nausea ~24–33% (label)
Cardiovascular-outcomes trial	SELECT — published (NEJM 2023)	SURMOUNT-MMO — ongoing
Boxed warning	Thyroid C-cell tumors	Thyroid C-cell tumors
FDA approval (weight loss)	Wegovy® — yes	Zepbound® — yes
Compounded version (not FDA-approved)	Yes (patient-specific, 503A pharmacies)	Yes (patient-specific, 503A pharmacies)

Figures are from clinical trials of the FDA-approved branded medications and are population averages, not individual guarantees or predictions for any compounded product. Prices are as of June 2026 and change frequently.

How they work: the mechanism difference

Tirzepatide vs semaglutide starts with a real biological difference, not just a brand one. Semaglutide is a GLP-1 receptor agonist: it mimics glucagon-like peptide-1, the gut hormone released after eating. GLP-1 receptor activation reduces appetite, slows gastric emptying, stimulates insulin release when blood sugar is high, and suppresses glucagon. All GLP-1 agonists share this pathway.

Tirzepatide is a dual GIP/GLP-1 agonist — a single molecule engineered to activate both the GLP-1 receptor and the GIP receptor (glucose-dependent insulinotropic polypeptide). GIP is a second gut hormone that also influences insulin secretion, fat metabolism, and possibly satiety signaling. The two receptors are expressed in different tissues, and activating both together appears to have effects on body weight that go beyond what either target alone produces. The exact contribution of GIP activity in humans remains an area of active study, and individual responses vary.

In practical terms, the dual mechanism is the leading hypothesis for why tirzepatide has produced consistently higher average weight-loss numbers than semaglutide in clinical trials — but mechanism alone does not predict how any individual will respond. A clinician will weigh your full medical profile, not just the headline trial numbers.

Head-to-head: what SURMOUNT-5 actually showed

For years, clinicians and patients had to compare these two molecules using separate trials with different patient populations, different protocols, and different durations — an imperfect approach. SURMOUNT-5 (published in the New England Journal of Medicine, 2025) was the first randomized controlled trial to place tirzepatide and semaglutide head-to-head in adults with obesity but without type 2 diabetes, at maximum tolerated doses, over 72 weeks.

The result: participants on the FDA-approved tirzepatide lost approximately 20.2% of body weight on average, compared with approximately 13.7% for the FDA-approved semaglutide — a roughly 6.5-percentage-point gap favoring tirzepatide. A higher proportion of tirzepatide participants also reached the ≥20% weight-loss threshold.

Notably, the rate of GI side effects leading to trial discontinuation was slightly lower in the tirzepatide arm in that study, though both were broadly similar in GI tolerability profile.

Important framing: these numbers describe the branded, FDA-approved medications studied in that specific trial — they are not outcomes for any compounded version of these drugs, and they are population averages, not individual guarantees. Individual results vary considerably based on dose, adherence, baseline characteristics, and other factors.

Earlier single-arm trial data

Before SURMOUNT-5, the most-cited figures came from separate trials. The STEP-1 trial of the FDA-approved branded semaglutide (Wilding et al., NEJM, 2021) showed approximately 14.9% average weight loss over 68 weeks in adults with obesity or overweight with a comorbidity. The SURMOUNT-1 trial of the FDA-approved branded tirzepatide (Jastreboff et al., NEJM, 2022) showed approximately 20.9% average weight loss at the 15 mg dose over 72 weeks — the highest dose studied. These separate trials enrolled different patients under different conditions, so direct comparison was always provisional. SURMOUNT-5 resolved the key uncertainty with a properly controlled head-to-head design.

Side effects and tolerability

Both molecules share a GI-dominant side-effect profile: nausea, diarrhea, constipation, and vomiting are the most common, typically peaking within the first few weeks after each dose increase and improving with time. On the Wegovy® FDA label, nausea is reported in approximately 44% of participants, compared with approximately 24–33% on the Zepbound® label. In SURMOUNT-5, more participants discontinued for GI reasons on semaglutide than on tirzepatide — but cross-trial pooled analyses do not establish tirzepatide as definitively easier to tolerate across all GI endpoints, and tolerability is highly individual.

Both drugs carry the same boxed warning for thyroid C-cell tumors based on animal data, and both are contraindicated with a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2). Additional shared risks include pancreatitis, gallbladder disease, heart rate increase, and kidney injury. Neither is for use during pregnancy. A prescribing clinician will review your full history before recommending either.

Slow, gradual dose titration remains the most reliable strategy for reducing GI side effects on either medication. Do not compare your experience to someone else's based on trial averages.

Cardiovascular and metabolic evidence

This is where semaglutide currently has a meaningful advantage in the published data. The SELECT trial (Lincoff et al., NEJM, 2023) enrolled more than 17,000 adults with established cardiovascular disease and obesity but without diabetes, and found that the FDA-approved branded semaglutide reduced the risk of major adverse cardiovascular events (MACE) by approximately 20% relative to placebo over a median of ~33 months. This was the first large cardiovascular-outcomes trial of a GLP-1 agonist in patients without diabetes, and it strengthened semaglutide's evidence base beyond weight loss.

Tirzepatide does not yet have published cardiovascular-outcomes data. The SURMOUNT-MMO trial — a dedicated cardiovascular-outcomes study — is ongoing. Until those results are published, clinicians treating patients with significant cardiovascular risk may factor SELECT's evidence into the prescribing decision. This does not mean tirzepatide is less safe; it means the long-term cardiovascular data for tirzepatide are still being gathered.

Per NIDDK guidance, all prescription weight-loss medications should be discussed with a clinician in the context of your full health history and individual risk profile.

Who tends to choose which

No clinical guideline mandates one molecule over the other for all patients with obesity. What tends to drive the clinical decision:

• Highest average weight-loss numbers in the trial data: tirzepatide. The SURMOUNT-5 head-to-head advantage (~6.5 percentage points) is meaningful and was achieved in a well-designed trial. For patients whose primary goal is maximal weight loss and who have no contraindications favoring one drug over the other, the current evidence tilts toward tirzepatide.
• Published cardiovascular outcomes data: semaglutide. SELECT gives clinicians treating high-cardiovascular-risk patients an additional piece of evidence that tirzepatide does not yet have. This may tip the clinical calculus for certain patients.
• Tolerability: individual. Some people tolerate one significantly better than the other. The label nausea rates favor tirzepatide, but this does not hold uniformly across individuals or GI endpoints.
• Cost and access: brand self-pay for Wegovy® runs approximately $349/month via NovoCare, and Zepbound® approximately $299–$449/month via LillyDirect (as of June 2026); insurance coverage varies significantly. See our 2026 GLP-1 cost guide for a full breakdown, including how to compare compounded options.

The prescribing decision is a clinician's call based on your full health profile — not a self-service comparison exercise. What this article gives you is the evidence, so you can have an informed conversation.

Zepbound vs Wegovy — and Mounjaro vs Ozempic

If you've been comparing Zepbound® vs Wegovy® or Mounjaro® vs Ozempic®, you are comparing exactly these two molecules. Tirzepatide is marketed as Mounjaro® for type 2 diabetes and Zepbound® for chronic weight management. Semaglutide is marketed as Ozempic® for type 2 diabetes and cardiovascular risk, and Wegovy® for chronic weight management.

The weight-loss context is Zepbound® vs Wegovy®, and the SURMOUNT-5 head-to-head result applies directly: both trials enrolled the weight-management-indicated product at maximum tolerated doses. For the diabetes context (Mounjaro® vs Ozempic®), the evidence picture also includes head-to-head glycemic data, which is a different comparison. See our Mounjaro vs Ozempic breakdown for that detail, and our Ozempic vs Wegovy explainer for what distinguishes the semaglutide formulations from each other.

What about compounded semaglutide and tirzepatide?

Compounded semaglutide and compounded tirzepatide are patient-specific preparations of these active molecules, made by state-licensed 503A compounding pharmacies when a licensed clinician determines it is appropriate for the patient. They are not FDA-approved, not therapeutically equivalent to Wegovy®, Ozempic®, Zepbound®, or Mounjaro®, and were not studied in any of the trials cited in this article. No efficacy or safety number from STEP-1, SURMOUNT-1, SURMOUNT-5, or SELECT applies to any compounded product.

The primary reason patients use compounded versions is cost and access: FDA-approved brand self-pay prices are substantially higher, and insurance coverage is inconsistent. Compounded versions are legally available when prescribed by a licensed clinician as a patient-specific preparation and are not FDA-approved drugs. For a full cost comparison of brand vs compounded options, see our brand vs compounded GLP-1 guide and the compounded semaglutide vs Wegovy comparison. Current compounded program pricing is also tracked in Nouri's open GLP-1 telehealth pricing dataset.

Nouri offers compounded semaglutide and compounded tirzepatide as part of one complete program — clinician-guided treatment (when prescribed) plus a personalized nutrition plan and a movement plan, at one all-inclusive price, any dose. Semaglutide from $120/mo on the 6-month plan ($720 billed every 6 months) or $145/mo on the 3-month plan ($435 every 3 months). Tirzepatide from $175/mo on the 6-month plan ($1,050 billed every 6 months) or $199/mo on the 3-month plan ($597 every 3 months). Medications are prepared by Jungle Jim's Pharmacy (a state-licensed 503A pharmacy in Fairfield, OH) and VialsRX, and shipped discreetly in all 50 states. The program is backed by The Nouri Promise: if you're not satisfied in your first 30 days, you get a full refund — available on 3-month and 6-month plans.

Not all applicants qualify; a U.S.-licensed physician reviews each intake before any medication is prescribed.

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Related comparisons

• Which GLP-1 Is Most Effective for Weight Loss?
• Which GLP-1 Has the Fewest Side Effects?
• Ozempic vs Wegovy: Same Molecule, Different Uses
• Zepbound vs Ozempic
• Mounjaro vs Ozempic
• Compounded Semaglutide vs Wegovy: Cost and Key Differences
• Compounded Tirzepatide vs Zepbound: Cost and Key Differences
• How Much Does a GLP-1 Cost in 2026?

Frequently asked questions

Is tirzepatide better than semaglutide for weight loss?

In the head-to-head SURMOUNT-5 trial of the FDA-approved branded drugs, tirzepatide produced greater average weight loss (~20.2%) than semaglutide (~13.7%) over 72 weeks. Whether it is "better" for any given person depends on tolerability, individual health factors, cardiovascular risk, cost, and clinical judgment. These are trial averages for the branded medications, not outcome guarantees, and they do not apply to compounded versions.

Which has fewer side effects, tirzepatide or semaglutide?

Both share the same GI-dominant side-effect class. On the FDA labels, semaglutide's nausea rate (~44%) is higher than tirzepatide's (~24–33%), and in SURMOUNT-5 fewer participants stopped tirzepatide for GI reasons — but pooled analyses across all GI endpoints do not confirm a definitive winner, and tolerability is highly individual. Slow dose titration helps most on either drug.

Can you switch from semaglutide to tirzepatide?

Many patients do, under a clinician's guidance, typically restarting at a low introductory dose of tirzepatide. A licensed provider should manage the transition and determine the appropriate starting dose.

Is Zepbound® the same as tirzepatide, and Wegovy® the same as semaglutide?

Yes. Zepbound® and Mounjaro® are brand names for tirzepatide; Wegovy® and Ozempic® are brand names for semaglutide. "Zepbound® vs Wegovy®" is the branded version of this comparison, and the SURMOUNT-5 head-to-head data applies to it directly.

How much more weight do you lose on tirzepatide vs semaglutide?

In SURMOUNT-5, the FDA-approved tirzepatide produced approximately 20.2% average body-weight loss vs approximately 13.7% for the FDA-approved semaglutide over 72 weeks — roughly a 6.5-percentage-point difference. These are population averages from the branded medications and do not represent a guaranteed result for any individual or for any compounded product.

Does tirzepatide or semaglutide have better cardiovascular evidence?

Semaglutide currently leads on published CV-outcomes data. The SELECT trial (NEJM, 2023) demonstrated a ~20% relative risk reduction in major cardiovascular events for the FDA-approved branded semaglutide in high-risk patients with obesity but without diabetes. Tirzepatide's cardiovascular-outcomes trial (SURMOUNT-MMO) is still running. A clinician can help weigh this when choosing between the two.

Sources & references

1. Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. STEP-1, NEJM 2021 — Tier 1
2. Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity. SURMOUNT-1, NEJM 2022 — Tier 1
3. SURMOUNT-5 head-to-head: tirzepatide vs semaglutide in obesity, NEJM 2025 — Tier 1
4. Lincoff AM et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. SELECT, NEJM 2023 — Tier 1
5. Wegovy® (semaglutide) FDA Prescribing Information, 2026 — Tier 1
6. Zepbound® (tirzepatide) FDA Prescribing Information, 2024 — Tier 1
7. FDA: Human Drug Compounding — Tier 1
8. FDA: Postmarket Drug Safety Information — GLP-1 compounding concerns — Tier 1
9. NIDDK: Prescription Medications to Treat Overweight and Obesity — Tier 1
10. Nouri GLP-1 Telehealth Pricing Dataset 2026 (HuggingFace) — Nouri pricing data

Medically reviewed by Amber Patel, MD · Nouri Editorial Team · Last reviewed June 29, 2026. Nouri content is reviewed by a licensed physician and updated as guidance changes.

This article is general education, not medical advice — talk to a licensed clinician about what is right for you. Ozempic®, Wegovy®, and Rybelsus® (semaglutide) are registered trademarks of Novo Nordisk A/S; Mounjaro® and Zepbound® (tirzepatide) are registered trademarks of Eli Lilly and Company; Nouri is not affiliated with, endorsed by, or sponsored by these companies. Clinical-trial results described here are from published research on the FDA-approved branded medications only; compounded semaglutide and compounded tirzepatide have not been studied in these trials, are not FDA-approved, and are not the same as — or therapeutically equivalent to — the brand-name drugs. Compounded medications are patient-specific preparations prescribed only when a licensed clinician determines they are appropriate for the individual patient; not all applicants qualify. GLP-1 medications carry a boxed warning for thyroid C-cell tumors; are contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2; and carry additional risks including pancreatitis, gallbladder disease, and heart rate increase. They are not for use during pregnancy. Individual results vary. Brand prices cited are approximate self-pay list prices as of June 2026 via NovoCare and LillyDirect and are subject to change. Nouri program prices are as of June 2026; visit joinnouri.com/becoming for current pricing.