Yes, Zepbound is FDA approved. It received its first approval on November 8, 2023, for chronic weight management in adults with obesity or overweight with at least one weight-related health condition. It then received a second approval on December 20, 2024, making it the first medication ever approved for moderate to severe obstructive sleep apnea in adults with obesity.
Zepbound is made by Eli Lilly and contains the active ingredient tirzepatide, a once-weekly injection. Here’s what you should know about who qualifies, how well it works, and what to expect.
What Zepbound Is Approved to Treat
Zepbound currently has two FDA-approved uses. The first is chronic weight management in adults who meet specific BMI thresholds: a BMI of 30 or greater (obesity), or a BMI of 27 or greater (overweight) along with at least one weight-related condition such as high blood pressure, high cholesterol, type 2 diabetes, sleep apnea, or cardiovascular disease. Both approvals require that the medication be used alongside a reduced-calorie diet and increased physical activity.
The second approval covers moderate to severe obstructive sleep apnea in adults with obesity. This made Zepbound the first drug the FDA has ever approved specifically for that condition, which affects millions of people who experience repeated breathing interruptions during sleep.
How Zepbound Differs From Mounjaro
Zepbound and Mounjaro are molecularly identical medications. Both contain tirzepatide, and both are manufactured by Eli Lilly. The difference is entirely in their FDA-approved uses and how they’re marketed. Mounjaro is approved for type 2 diabetes. Zepbound is approved for weight management and sleep apnea. This distinction matters primarily for insurance coverage, since insurers typically cover a drug only for its approved indication.
How It Works
Tirzepatide activates two gut hormone receptors at once: GIP and GLP-1. These hormones are naturally released after eating and play roles in blood sugar regulation, appetite, and how quickly food moves through your digestive system. Most other medications in this class target only the GLP-1 receptor. By hitting both receptors simultaneously, tirzepatide produces a stronger combined effect on insulin response and appetite suppression than activating either one alone.
The drug is engineered with a fatty acid chain that lets it bind to a protein in your blood called albumin, which slows its breakdown and extends its active life to about five days. That’s what makes once-weekly dosing possible.
Weight Loss Results From Clinical Trials
In the SURMOUNT-1 trial, which studied adults with obesity or overweight over 72 weeks (about a year and a half), weight loss was substantial and dose-dependent. Participants on the 5 mg dose lost an average of 15% of their body weight. Those on 10 mg lost 19.5%, and the 15 mg group lost 20.9%. For context, a person weighing 250 pounds on the highest dose would lose roughly 52 pounds on average over that period.
These results placed tirzepatide among the most effective weight-loss medications studied to date, though individual results vary and the trials required participants to follow a reduced-calorie diet alongside the medication.
Dosing and How It’s Taken
Zepbound is a subcutaneous injection, meaning you inject it just under the skin, typically in the abdomen, thigh, or upper arm. The starting dose is 2.5 mg once per week for the first four weeks. That initial dose is not a treatment dose. It exists solely to let your body adjust and reduce the likelihood of side effects.
After four weeks, the dose increases to 5 mg weekly. From there, your doctor may increase it in 2.5 mg steps, waiting at least four weeks between each increase, up to a maximum of 15 mg per week. The gradual ramp-up is important because jumping to higher doses too quickly tends to worsen gastrointestinal side effects.
Side Effects and Safety Warnings
The most common side effects are gastrointestinal: nausea, diarrhea, vomiting, and constipation. These tend to be worst during the early weeks and after dose increases, then improve as your body adjusts.
Zepbound carries the FDA’s most serious label warning, a boxed warning, regarding the risk of thyroid C-cell tumors. In animal studies, tirzepatide caused these tumors in rodents. Whether this translates to humans isn’t fully established, but as a precaution, Zepbound is contraindicated for anyone with a personal or family history of medullary thyroid carcinoma or a condition called Multiple Endocrine Neoplasia syndrome type 2. It’s also contraindicated for anyone who has had a serious allergic reaction to tirzepatide, as cases of anaphylaxis and severe swelling have been reported.
Current Availability
Zepbound experienced significant supply shortages after its launch, making it difficult for many patients to fill prescriptions. The FDA added tirzepatide products to its drug shortage list, which temporarily opened the door for compounding pharmacies to produce custom versions. However, the FDA determined that the shortage was resolved as of October 2024, with Eli Lilly confirming it can meet or exceed demand for all dose strengths of Zepbound in the United States. The company has also built up finished product reserves and scheduled additional production to stay ahead of demand. Zepbound vial products were never on the shortage list.
Even with supply stabilized, cost remains a barrier. Without insurance coverage, Zepbound’s list price is over $1,000 per month. Coverage varies widely by insurer, and many plans still exclude weight-loss medications or impose strict prior authorization requirements.