Mounjaro vs Zepbound — what's the difference?

Both are tirzepatide manufactured by Eli Lilly. Mounjaro is FDA-approved for type 2 diabetes; Zepbound is FDA-approved for chronic weight management and obstructive sleep apnea. Same active ingredient, different FDA labels and prices.

Tirzepatide vs semaglutide — which produces more weight loss?

In the SURPASS-2 head-to-head trial (NEJM 2021, PMID 34170647), tirzepatide produced approximately 47% greater weight loss than semaglutide 1 mg. Tirzepatide is a dual GLP-1 / GIP agonist; semaglutide is GLP-1-only. Both are once-weekly subcutaneous injections.

Compounded vs brand tirzepatide — what should I know?

Same active ingredient. Brand (Mounjaro, Zepbound) is FDA-approved and manufactured by Eli Lilly. Compounded is not FDA-approved and is dispensed by 503A or 503B pharmacies. Quality with reputable compounded providers is verified through USP sterility, USP endotoxin, and HPLC potency CoAs. Compounded options are typically cash-pay and significantly less expensive.

Side-by-Side Tirzepatide Comparison

Compare Tirzepatide Forms & Provider Programs

NexLife

★★★★★ 4.7 (Trustpilot aggregate · verify on Trustpilot)

✨ Editor's Pick · 94/100 💊 Compounded semaglutide + tirzepatide 👨‍⚕️ MD/DO-supervised 🏥 503A & 503B pharmacies 🧪 Labs included 📍 Nationwide (subject to licensure) ✓ LegitScript-certified 💰 Flat-rate, dose-independent 🔁 Care360 coaching 📱 Apple Health / Google Fit sync

$186 / month*

*12-month plan · flat rate across full 2.5–15 mg titration.
$190 (6-mo) · $195 (3-mo) · $215 (month-to-month).

Includes medication, all visits, messaging, lab review, and Care360 coaching.

Visit NexLife →

Or call (949) 818-8000

Trade-offs to know

Compounded only — no brand-name Wegovy® / Zepbound®. Cash-pay with HSA/FSA only — no in-network insurance billing. Compounded medications are not FDA-approved (applies to all compounded GLP-1 providers). Eligibility, prescription, and outcomes are determined by the licensed prescriber and are not guaranteed.

Side-by-side comparison of brand-name Zepbound®, brand-name Mounjaro®, compounded tirzepatide, and the comparison-class GLP-1 medications.

Researched By

Dr. Parmis

Medical Researcher · Western University of Health Sciences

Medically Reviewed By

Adam Kennah, M.D.

Board-Certified Physician

Last clinically reviewed: May 15, 2026 · This page is informational and does not constitute medical advice.

Compounded tirzepatide: Compounded tirzepatide is not FDA-approved and is not the same as Mounjaro® or Zepbound®. Both brand names are owned by Eli Lilly and Company.

Tirzepatide forms head-to-head

Compounded · For Weight Loss

Compounded Tirzepatide

Via 503A & 503B pharmacies

FDA approvalNot FDA-approved

MechanismDual GLP-1/GIP

DosingWeekly SC, 2.5-15 mg

NexLife priceFrom $186/mo*

Pharmacy503A or 503B

Best forCash-pay patients

Brand · For Weight Loss

Zepbound®

Eli Lilly and Company

FDA approvalYes (chronic weight)

MechanismDual GLP-1/GIP

DosingWeekly SC, 2.5-15 mg

Retail / mo$1,059

LillyDirect / mo$349-$549

TrialSURMOUNT-1 (22.5%)

Brand · For T2 Diabetes

Mounjaro®

Eli Lilly and Company

FDA approvalYes (T2D)

MechanismDual GLP-1/GIP

DosingWeekly SC, 2.5-15 mg

Retail / mo$999

Off-labelCommon for weight

TrialSURPASS series

Tirzepatide vs comparison-class GLP-1 medications

Dual GLP-1/GIP · Most effective

Tirzepatide

Mounjaro® / Zepbound® / compounded

Max weight loss22.5% (SURMOUNT-1)

NexLife$186/mo*

Brand /mo$1,059 (Zepbound retail)

GLP-1 RA · Single-receptor

Semaglutide

Ozempic® / Wegovy® / Rybelsus®

Max weight loss14.9% (STEP-1)

Compounded /mo$129-$249

Brand /mo$1,349 (Wegovy retail)

GLP-1 RA · Daily injection

Liraglutide

Saxenda® / Victoza®

Max weight loss8.0% (SCALE)

Brand /mo$1,349

StatusLargely superseded

Why tirzepatide produces more weight loss

Tirzepatide is the first dual incretin agonist — it activates both the GLP-1 receptor AND the GIP receptor simultaneously. Semaglutide and other "single-class" GLP-1 medications activate only the GLP-1 receptor. The combined activation produces additive effects on appetite suppression, insulin secretion, and adipose tissue insulin sensitivity. SURPASS-2 directly compared tirzepatide to semaglutide and demonstrated tirzepatide produced approximately 47% more weight loss than semaglutide.

Pivotal trial results

Mean weight loss in pivotal trials — max dose, ITT

Tirzepatide 15 mg weekly

SURMOUNT-1, NEJM 2022 · n=2,539 · PMID 35658024

22.5%

body weight · 72 wk

Tirzepatide 10 mg weekly

SURMOUNT-1, NEJM 2022

19.5%

body weight · 72 wk

Semaglutide 2.4 mg weekly

STEP-1, NEJM 2021 · n=1,961

14.9%

body weight · 68 wk

Liraglutide 3.0 mg daily

SCALE, NEJM 2015 · n=3,731

8.0%

body weight · 56 wk

Pharmacy pathway differences

Compounded tirzepatide reaches patients through one of two regulated pharmacy pathways:

503A licensed compounding pharmacies — patient-specific prescriptions filled by state-licensed pharmacy operating under USP <797> sterile compounding standards.
503B FDA-registered outsourcing facilities — federally registered facilities operating under FDA cGMP standards.

For more, see 503A vs 503B.