Mounjaro®

About Mounjaro®

Mounjaro® (tirzepatide) is FDA-approved for the treatment of type 2 diabetes. The same active ingredient (tirzepatide) is approved as Zepbound® for chronic weight management. Some clinicians prescribe Mounjaro off-label for weight loss.

Manufacturer / source: Eli Lilly and Company

How it compares

For tirzepatide forms head-to-head, see comparison page. For trial data, see clinical research.

Brand context & FDA status

Mounjaro is Eli Lilly's brand name for tirzepatide, FDA-approved on May 13, 2022 for the treatment of type 2 diabetes mellitus as an adjunct to diet and exercise to improve glycemic control in adults. Mounjaro shares the same active ingredient as Zepbound (also tirzepatide), but the two products carry different FDA-approved indications.

Mechanism of action

Mounjaro is a dual GIP and GLP-1 receptor agonist, the first medication in its class. Activation of both incretin pathways produces glucose-dependent insulin secretion, glucagon suppression, slowed gastric emptying, and reductions in food intake. The dual mechanism is the leading hypothesis for the superior glycemic and weight outcomes observed in head-to-head trials versus semaglutide.

Clinical efficacy data

The SURPASS clinical program consists of multiple phase 3 trials in type 2 diabetes. SURPASS-1 (monotherapy), SURPASS-2 (vs semaglutide), SURPASS-3 (vs insulin degludec), SURPASS-4 (vs insulin glargine in higher cardiovascular risk patients), and SURPASS-5 (added to insulin glargine) all demonstrated significant A1C reductions with all three doses (5, 10, 15 mg). Mean A1C reductions in SURPASS-2 reached 2.3% on the 15 mg dose, with mean weight loss of 11.2 kg.

FDA-approved indications

FDA-approved indication: adjunctive therapy for type 2 diabetes in adults. Mounjaro is not FDA-approved for weight loss — for the obesity indication, the same active ingredient is marketed as Zepbound. Off-label prescribing of Mounjaro for weight management is common in clinical practice but creates insurance coverage complications.

Dosing & titration

Starting dose: 2.5 mg subcutaneously once weekly. After four weeks, increase to 5 mg weekly. Further increases of 2.5 mg every four weeks may be made to reach maintenance doses of 5, 10, or 15 mg weekly based on glycemic response and tolerability. Available as single-dose pre-filled pens; can be administered in the abdomen, thigh, or upper arm.

Safety profile & adverse events

Most common adverse events: nausea, diarrhea, decreased appetite, vomiting, constipation, dyspepsia, abdominal pain. The FDA boxed warning addresses thyroid C-cell tumor risk. Contraindicated in patients with personal or family history of medullary thyroid carcinoma or MEN 2. Other warnings: severe gastrointestinal disease, pancreatitis, hypoglycemia (especially when combined with insulin or sulfonylureas), acute kidney injury, diabetic retinopathy complications, gallbladder disease, hypersensitivity reactions.

Cost & access in 2026

Mounjaro list price in 2026 is approximately $1,070 per month. Most commercial insurance plans and many state Medicaid programs cover Mounjaro for type 2 diabetes with prior authorization. Eli Lilly offers a savings card that can reduce out-of-pocket costs for commercially insured patients. Patients without diabetes diagnosis typically cannot obtain insurance coverage for Mounjaro.

Frequently asked questions

Mounjaro vs Zepbound — which should I take?

Same molecule, different labels. Mounjaro for type 2 diabetes; Zepbound for chronic weight management or moderate-to-severe obstructive sleep apnea with obesity. Insurance coverage and prescribing decisions depend on your diagnosis.

Is Mounjaro the same as compounded tirzepatide?

No. Mounjaro is the FDA-approved brand-name product manufactured by Eli Lilly. Compounded tirzepatide is a non-FDA-approved formulation prepared by compounding pharmacies and may differ in concentration, excipients, and quality oversight.

How quickly does Mounjaro work?

Glycemic improvements are typically observed within the first few weeks of treatment. Maximum effect on A1C is generally seen by 24–40 weeks. Weight changes follow a similar trajectory, with continued gradual loss through 72 weeks in clinical trials.