Side-by-Side Comparison

Factor	Mounjaro	Zepbound
Active Ingredient	Tirzepatide	Tirzepatide
Manufacturer	Eli Lilly	Eli Lilly
FDA Approval Year	2022	2023
FDA Indication	T2D primary	Obesity / chronic weight management
Formulation	Weekly subcutaneous injection	Weekly subcutaneous injection
Dosing Frequency	Weekly	Weekly
Starting Dose	2.5 mg	2.5 mg
Maximum Dose	15 mg	15 mg
Weight Loss (key trial)	~15–21% body weight in SURPASS trials (T2D); up to 22.5% in SURMOUNT-1 (obesity label/Zepbound)	22.5% mean body weight reduction at 15 mg (SURMOUNT-1, 72 weeks)
Key Trial	SURPASS-2	SURMOUNT-1
Cash Price (est. Q1 2026)	$1,000–$1,100/month	$1,000–$1,100/month
CVD Outcome Benefit	No / Not established	No / Not established

Cost estimates based on Q1 2026 data. Weight loss from named pivotal trials. Individual results vary. Verify current pricing with your pharmacy.

Which Is Right for You?

The "better" medication depends entirely on your individual medical history, insurance coverage, treatment goals, and tolerability. Here are key decision scenarios:

★ Primary goal is maximum weight loss

Based on clinical trial data, Zepbound has demonstrated higher percentage weight loss in pivotal trials. Discuss whether the magnitude of difference is clinically meaningful for your situation with your prescriber.

★ You have type 2 diabetes as primary concern

Mounjaro is FDA-approved for T2D management. Your prescriber will consider HbA1c targets, cardiovascular risk, renal function, and cost when choosing between them.

★ Cost is a primary factor

Cash prices differ significantly between medications. Mounjaro costs approximately $1,000–$1,100/month/month without insurance; Zepbound costs approximately $1,000–$1,100/month/month. Both manufacturers offer savings programs for commercially insured patients. Use our Cost Estimator → to compare your specific situation.

★ You are already taking one of these medications

Since Mounjaro and Zepbound contain the same active ingredient (Tirzepatide), switching between them involves changing the indication and dose — not the molecule. Your prescriber may transition you based on insurance coverage or clinical goals with minimal pharmacological adjustment.

Side Effect Comparison

Mounjaro Common Side Effects

•Nausea
•Diarrhea
•Vomiting
•Constipation
•Abdominal Pain
•Injection Site Reaction
•Fatigue

Zepbound Common Side Effects

•Nausea
•Diarrhea
•Vomiting
•Constipation
•Abdominal Pain
•Injection Site Reaction
•Fatigue

Both medications share GI-related side effects as the most common adverse events. The profile is very similar because both belong to the GLP-1 receptor agonist class (or include GLP-1 agonism). Differences in tolerability are individual and cannot be predicted in advance.

Cost Comparison

Scenario	Mounjaro	Zepbound
Cash pay / no insurance	$1,000–$1,100/month/mo	$1,000–$1,100/month/mo
Commercial insurance	$25/month with Eli Lilly savings card for eligible commercially insured patients	$25/month with Eli Lilly savings card for eligible commercially insured patients
Mfr. savings program	Eli Lilly Mounjaro Savings Card	Eli Lilly Zepbound Savings Card

Estimated based on Q1 2026 data. Always verify with your pharmacy or plan.

💰 Estimate your personalized monthly cost →

Switching Guidance

If switching between Mounjaro and Zepbound, consult your prescriber about the transition protocol. Key considerations include:

Whether to allow a washout period or transition directly
Starting dose for the new medication (may not match your current dose)
Insurance prior authorization requirements for the new medication
Monitoring frequency during transition

See our drug conversion calculator → for dose equivalency guidance.

Mounjaro vs Zepbound: Which Is Better for Weight Loss in 2026?