Zepbound is Eli Lilly's brand of tirzepatide for weight management. It was approved in November 2023, gained a second indication — obstructive sleep apnea in adults with obesity — in December 2024, and is the same molecule as Lilly's diabetes brand, Mounjaro, sold under a separate approval with a separate label. It is a once-weekly injection, now in four forms.
This page covers the brand: what the label says it is for and what it is not, how the molecule works, the forms it comes in and how its label has changed. It is built from the current prescribing information (Eli Lilly, DailyMed version effective 28 August 2026) and FDA's approval records, read on 3 October 2026. What it achieved in its trials is on our tirzepatide review; the molecule itself is described in Peptide Lexicon's tirzepatide entry.
What it is approved for
The label's two indications, both "in combination with a reduced-calorie diet and increased physical activity":
- Weight: "to reduce excess body weight and maintain weight reduction long term in adults with obesity or adults with overweight in the presence of at least one weight-related comorbid condition."
- Sleep apnea: "to treat moderate to severe obstructive sleep apnea (OSA) in adults with obesity." The sleep-apnea evidence is on GLP-1s and sleep apnea.
And the label's one limitation of use: Zepbound "contains tirzepatide. Coadministration with other tirzepatide-containing products or with any glucagon-like peptide-1 (GLP-1) receptor agonist is not recommended."
Three things it is not approved for, each a common assumption:
- Type 2 diabetes. That is Mounjaro's indication. People with diabetes were included in a Zepbound weight trial, but treating diabetes is not on Zepbound's label. How the two brands divide — including an age line that runs the opposite way to the semaglutide brands — is on Mounjaro vs Zepbound.
- Children or adolescents. Both indications are for adults.
- Heart protection. Zepbound has no cardiovascular indication — see the label history below.
How it works
The label's mechanism section describes tirzepatide as "a GIP receptor and GLP-1 receptor agonist" — one molecule that acts on the receptors for two gut hormones. In the label's words, GLP-1 "is a physiological regulator of appetite and caloric intake", "nonclinical studies suggest the addition of GIP may further contribute to the regulation of food intake", and in animal studies tirzepatide "distributes to and activates neurons in brain regions involved in regulation of appetite and food intake". It also delays stomach emptying, which is behind several of its side effects.
Structurally, tirzepatide is a 4,813.53-dalton peptide built on the GIP sequence, with two unusual amino acids (aminoisobutyric acid at positions 2 and 13) and a 20-carbon fatty diacid attached by a linker. That fatty chain "enables albumin binding and prolongs the half-life" to about five days, which is what makes once-weekly injection possible. The two hormones are explained on GIP and GLP-1, and the class as a whole on how GLP-1 works.
The four forms it comes in
| Presentation | Doses per unit | Approved |
|---|---|---|
| Single-dose pen | 1 (box of 4) | With the brand, 8 November 2023 |
| Single-dose vial | 1 | Added later; sold singly and in packs of 4 |
| Multi-dose vial | 4 | 7 January 2026 (NDA 217806/S-037) |
| KwikPen | 4 | 20 January 2026 (NDA 217806/S-002) |
Label section 16.1; FDA approval letters. Each comes in the same six strengths, one strength per unit. The multi-dose forms carry a preservative, need a needle and syringe or a pen needle, and are discarded 30 days after first use; the device is described on the Zepbound KwikPen page, and storage for every form on GLP-1 pen storage. The forms also differ in price and in which savings routes apply — set out on Zepbound cost.
How the label has changed
Zepbound's approval file (NDA 217806) records each change FDA has approved. The ones that changed what the label says to a reader:
| Date | Supplement | What changed |
|---|---|---|
| 8 November 2023 | Original | Approved for chronic weight management |
| December 2024 | S-013 | Obstructive sleep apnea indication added (label Recent Major Changes, 12/2024) |
| 25 September 2025 | S-031 | Section 8.2, Lactation, revised |
| 7 January 2026 | S-037 | Multi-dose vial added |
| 20 January 2026 | S-002 | KwikPen added, 797 days after the application |
| 25 February 2026 | S-042 | Class-wide GI warnings added (intestinal obstruction, severe constipation including faecal impaction); suicidal ideation warning removed at FDA's request |
| 26 August 2026 | S-041 | SURPASS-CVOT results added to the diabetic-retinopathy warning |
Drugs@FDA submission history and FDA approval letters for NDA 217806, read 3 October 2026.
Two rows deserve a sentence each.
The suicidal-ideation warning came out at FDA's request, not Lilly's. FDA had opened a safety-signal review of suicidal ideation across the GLP-1 class in July 2023. On 13 January 2026 it asked Lilly to remove the information, and the February 2026 approval took out the former section 5.9, "Suicidal Ideation and Behavior", and the words "depression or thoughts of suicide" from the Medication Guide's list of possible side effects. The approval letter records the request and the removal; it does not publish FDA's reasoning. What the evidence on mood shows is on GLP-1s and depression.
The August 2026 heart-trial update is easy to misread. Tirzepatide's cardiovascular outcomes trial, SURPASS-CVOT, compared it with dulaglutide in adults with type 2 diabetes and established cardiovascular disease. Its results supported a cardiovascular indication for Mounjaro. On Zepbound's label, FDA's letter says the supplement added the trial's information to the warning on diabetic retinopathy and aligned the patient counselling text — no cardiovascular indication was added. (FDA letter, NDA 217806/S-041.) A Zepbound reader who has heard "tirzepatide cuts heart risk" should know that claim belongs to another label and another population.
The warnings
The label carries a boxed warning: tirzepatide caused thyroid C-cell tumours in rats, and the human relevance "has not been determined"; Zepbound is contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN 2. Its other warnings — pancreatitis, gallbladder disease, severe gastrointestinal reactions, kidney injury from dehydration, hypersensitivity, low blood sugar, retinopathy in people with diabetes, aspiration under anaesthesia, and never sharing a KwikPen — and how often each was seen are on Zepbound side effects.
Who makes it, and how people get it
Eli Lilly and Company holds the approval. Zepbound is dispensed at ordinary pharmacies with a prescription and through Lilly's own pharmacy service, LillyDirect. Savings-card terms are on the Zepbound savings card page, and Medicare's temporary route on the Medicare GLP-1 Bridge. How it compares with the nearest rival brand is on Zepbound vs Wegovy, and against the diabetes brand of semaglutide on Zepbound vs Ozempic. Compounded tirzepatide is a different, unapproved product — see compounded tirzepatide vs Zepbound.
This page reports the label and FDA's records. It is not advice on whether Zepbound suits anyone; that decision belongs with a prescriber.
Sources
- Eli Lilly and Company, ZEPBOUND (tirzepatide) injection, prescribing information and Medication Guide, DailyMed set ID 487cd7e7-434c-4925-99fa-aa80b1cc776b, effective 2026-08-28 — Boxed Warning and sections 1, 3, 4, 5, 11, 12.1, 16.1, dailymed.nlm.nih.gov, read 3 October 2026.
- Eli Lilly and Company, ZEPBOUND prescribing information revised 12/2024 (S-013), Recent Major Changes, accessdata.fda.gov, read 3 October 2026.
- US Food and Drug Administration, supplement approval letters for NDA 217806: S-002 (20 January 2026), S-031 (25 September 2025), S-037 (7 January 2026), S-041 (26 August 2026, corrected letter), S-042 (25 February 2026), via accessdata.fda.gov, read 3 October 2026.
- US Food and Drug Administration, Drugs@FDA submission history for NDA 217806 and NDA 215866 (Mounjaro), via open.fda.gov, queried 3 October 2026.