How Long Has Zepbound Been Around? FDA Approval Timeline

Zepbound (tirzepatide) is one of the newest medications approved for chronic weight management in the United States. The FDA approved Zepbound on November 8, 2023, making it approximately one to two years old as of early 2025. This dual GIP/GLP-1 receptor agonist represents a significant advancement in obesity pharmacotherapy, offering a once-weekly subcutaneous injection for adults with obesity or overweight with weight-related comorbidities. In late 2024, the FDA expanded its indication to include obstructive sleep apnea treatment in adults with obesity, further broadening its clinical applications.

We offer compounded medications and Zepbound®. Compounded medications are prepared by licensed pharmacies and are not FDA-approved. References to Wegovy®, Ozempic®, Rybelsus®, Mounjaro®, or Saxenda®, or other GLP-1 brands, are informational only. Compounded and FDA-approved medications are not interchangeable.

Zepbound FDA Approval Timeline and Market Introduction

Zepbound (tirzepatide) is a relatively new medication in the weight management landscape. The US Food and Drug Administration (FDA) approved Zepbound on November 8, 2023, specifically for chronic weight management in adults with obesity or overweight with at least one weight-related comorbid condition. This makes Zepbound approximately one to two years old as of early 2025, representing one of the newer pharmacologic options available for weight loss in the United States.

The medication became commercially available in US pharmacies shortly after FDA approval in late 2023. Zepbound is manufactured by Eli Lilly and Company and is administered as a once-weekly subcutaneous injection. The approval was granted under the brand name Zepbound to distinguish it from tirzepatide's earlier indication—the same active ingredient was previously approved as Mounjaro for type 2 diabetes mellitus in May 2022.

In late 2024, the FDA expanded Zepbound's label to include treatment of obstructive sleep apnea (OSA) in adults with obesity, broadening its approved uses. Since its introduction, Zepbound has represented a significant addition to obesity pharmacotherapy as a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist specifically labeled for weight management. The medication is part of the evolving class of incretin-based therapies that have been introduced for both diabetes and obesity management over the past several years.

Development History of Tirzepatide for Weight Management

The development of tirzepatide as a weight management agent began well before Zepbound's 2023 approval, with research into dual GIP/GLP-1 receptor agonism dating back several years. Eli Lilly initiated the tirzepatide development program in the early 2010s, initially focusing on glycemic control in type 2 diabetes. However, researchers observed substantial weight loss as a consistent secondary outcome in diabetes trials, prompting dedicated investigation into tirzepatide's potential as an obesity treatment.

The pivotal moment came with the SURMOUNT clinical trial program, which was specifically designed to evaluate tirzepatide for chronic weight management in adults without diabetes. These Phase 3 trials began enrolling participants in 2019 and 2020, representing a strategic expansion of tirzepatide's therapeutic applications beyond glucose control. The decision to pursue a separate weight management indication reflected both the magnitude of weight loss observed and the recognition of obesity as a chronic disease requiring dedicated pharmacologic intervention.

Tirzepatide's mechanism of action—dual agonism at both GIP and GLP-1 receptors—distinguishes it from earlier incretin-based therapies that targeted only GLP-1 receptors. This approach was studied to determine its metabolic effects, including weight reduction. The development pathway involved extensive preclinical research, dose-finding studies, and ultimately the large-scale SURMOUNT trials that would provide the evidence base for FDA approval. The approximately four-year journey from trial initiation to regulatory approval represents a relatively standard timeline in pharmaceutical development for a medication addressing a significant medical need in obesity treatment.

Clinical Trials Leading to Zepbound's Approval

The FDA approval of Zepbound was primarily based on data from the SURMOUNT clinical trial program, which included multiple Phase 3 randomized controlled trials evaluating tirzepatide in adults with obesity or overweight. The landmark SURMOUNT-1 trial, published in The New England Journal of Medicine in 2022, enrolled 2,539 adults without diabetes and demonstrated that tirzepatide produced substantial weight loss compared to placebo over 72 weeks. Participants receiving the highest dose (15 mg weekly) achieved an average weight reduction of approximately 20.9% from baseline, significantly exceeding placebo and establishing tirzepatide as one of the most effective weight loss medications studied to date.

SURMOUNT-2, published in The Lancet in 2023, specifically evaluated tirzepatide in adults with both obesity and type 2 diabetes, demonstrating dual benefits of weight loss and glycemic improvement. SURMOUNT-OSA assessed tirzepatide in patients with obstructive sleep apnea, providing data that later supported the 2024 label expansion.

Separately, the SUMMIT program (not part of SURMOUNT) has evaluated tirzepatide in patients with heart failure with preserved ejection fraction. These various trials collectively enrolled thousands of participants across multiple countries, providing robust safety and efficacy data across demographic groups.

The clinical trial program revealed a dose-dependent response, with higher tirzepatide doses (10 mg and 15 mg weekly) producing greater weight loss than lower doses (5 mg). Common adverse effects included gastrointestinal symptoms such as nausea, diarrhea, vomiting, and constipation, typically mild to moderate in severity and decreasing over time. Serious adverse events were uncommon. According to the FDA label, important safety considerations include potential thyroid C-cell tumor risk (based on rodent studies) and contraindications in patients with personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2.

Current Availability and Prescribing Information

As of 2025, Zepbound is available by prescription in the United States for chronic weight management in adults with a body mass index (BMI) of 30 kg/m² or greater (obesity), or 27 kg/m² or greater (overweight) with at least one weight-related comorbid condition such as hypertension, type 2 diabetes, or dyslipidemia. The medication is also indicated for adults with obesity and obstructive sleep apnea. Zepbound is supplied as single-dose prefilled pens in six strengths: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg for once-weekly subcutaneous injection.

Prescribing clinicians typically initiate treatment at 2.5 mg weekly for four weeks, then escalate to 5 mg weekly, with potential further increases by 2.5 mg every 4 weeks as tolerated up to a maximum of 15 mg based on individual response and tolerability.

Zepbound requires a prescription from a licensed healthcare provider and is not available over-the-counter. Insurance coverage varies considerably, with some commercial plans covering the medication while others exclude weight management drugs from formularies. Patient assistance programs are available through the manufacturer for eligible individuals. Clinicians should verify insurance coverage prior to prescribing, as out-of-pocket costs can be substantial without coverage.

Prescribing information includes important contraindications and warnings. Zepbound is contraindicated in patients with personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2. The FDA label includes a boxed warning regarding thyroid C-cell tumors observed in rodent studies, though relevance to humans remains uncertain. Additional warnings address risks of pancreatitis, gallbladder disease, and acute kidney injury.

Zepbound may delay gastric emptying, potentially reducing the effectiveness of oral contraceptives. Women using oral contraceptives are advised to switch to a non-oral method or add a barrier method for 4 weeks after initiating Zepbound and after each dose escalation. The medication is not recommended during pregnancy due to potential fetal risk. Patients should not use Zepbound concurrently with other tirzepatide-containing products (such as Mounjaro), and safety with other weight-loss medications has not been established.

Patients should be counseled on proper injection technique, gastrointestinal side effects, and the importance of lifestyle modifications including reduced-calorie diet and increased physical activity as adjuncts to pharmacotherapy. Clinicians should monitor patients regularly for adverse effects and weight loss progress, adjusting treatment as clinically indicated.

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