Zepbound approval splits tirzepatide search demand across two brand names

The Food and Drug Administration approved Zepbound, Eli Lilly's tirzepatide injection, on Nov. 8, 2023, under new drug application 217806 ^[1]. The action was handled as a priority review, according to the FDA's approval history for the application ^[1].

The approval matters beyond the drug itself because tirzepatide was already on the US market under a different brand name, Mounjaro. One molecule now carries two brand identities, each with its own application, its own label and its own approved use. That split is the reason "are Mounjaro and Zepbound the same" has become one of the most-searched questions in the GLP-1 category.

What the FDA record actually shows

The Drugs@FDA entry for NDA 217806 lists Eli Lilly and Co as the applicant and shows a single original approval dated 11/08/2023, with the approval letter, the original label and the FDA review posted to the record ^[1].

The product listing under that application covers 24 entries, all tirzepatide solution for subcutaneous injection ^[1]. Six single-dose strengths appear at 2.5 mg/0.5 mL, 5 mg/0.5 mL, 7.5 mg/0.5 mL, 10 mg/0.5 mL, 12.5 mg/0.5 mL and 15 mg/0.5 mL, with a matching set listed under "Zepbound (Autoinjector)" ^[1]. A separate multi-dose format, the Zepbound KwikPen, is listed at 10 mg/2.4 mL, 20 mg/2.4 mL, 30 mg/2.4 mL, 40 mg/2.4 mL, 50 mg/2.4 mL and 60 mg/2.4 mL ^[1]. All are prescription-only, and none carry a therapeutic equivalence code, meaning no generic substitute is rated interchangeable with them in this record ^[1].

One detail in the FDA file underscores how closely the two brands are linked administratively: a later approval letter posted to the Zepbound record is a combined document covering both application 217806 and application 215866 ^[1]. The two brands are separate applications that Lilly manages in parallel.

What the FDA record does not contain is pricing, insurance coverage rules, or a side-by-side comparison of the Zepbound and Mounjaro labels. Those details are not in this source, so any claim about cost differences between the two brands is not established here.

Why it matters for patients

The practical effect of a two-brand structure is that the brand name on a prescription, not the molecule, usually drives what happens at the pharmacy counter. Insurers build formularies around brand-specific National Drug Codes and approved indications, so a plan can cover one tirzepatide brand and exclude the other even though the active ingredient is identical ^[1]. Prior authorization paperwork, manufacturer savings programs and pharmacy stock are all organized the same way.

The device options also differ by format rather than by dose alone. A person using a 10 mg dose could receive it as a 10 mg/0.5 mL single-dose product or through a KwikPen listed at 10 mg/2.4 mL, which is a different concentration in a multi-dose pen ^[1]. Anyone switching formats has a reason to confirm with a pharmacist which device they have been given.

For readers comparing the two brands, the single most useful fact is the one in the FDA record: Zepbound and Mounjaro contain the same active ingredient, tirzepatide, but they are approved under separate applications ^[1]. Whether a given plan treats them as interchangeable is a coverage question, not a chemistry question.

What happens next

The FDA record for NDA 217806 shows the label continued to change after the original approval. Supplements posted to the file include labeling updates on 03/28/2024 and 10/18/2024, an efficacy supplement for a new indication dated 12/20/2024, further labeling revisions on 02/07/2025 and 09/25/2025, and a manufacturing formulation supplement dated 01/07/2026 ^[1]. The specific content of each change is in the posted labels and letters rather than in the summary table ^[1].

This story reflects only the FDA application record for Zepbound. It is not medical advice.