When Will Tirzepatide Go Generic? Generic Makers Filed on the First Day the Law Allowed

There is no generic tirzepatide, and no public document says when there will be. But the question is not a guess either. FDA publishes the patent dates, the exclusivity dates and — less often read — a list of every generic application that has challenged a patent, with the date it was filed. Read together, they show that generic manufacturers have already lined up, and exactly how early they did it.

Everything below comes from three FDA files: the Orange Book data files (product, patent and exclusivity tables, dated 11 September 2026), the Paragraph IV Patent Certifications list (dated 14 September 2026), and the regulation that governs generic timing, 21 CFR 314.107 and 314.108. All were downloaded and read on 4 October 2026.

First: tirzepatide is the generic name

Much of the search for "Zepbound generic name" or "Mounjaro generic" is a vocabulary question. Tirzepatide is the non-proprietary name of the molecule, and it is the same molecule in both brands:

All 48 listed products belong to Eli Lilly. None is an abbreviated application — the type a generic manufacturer files. A generic name is on every box; a generic drug does not yet exist. How the two brands differ beyond the label is on Mounjaro vs Zepbound, and the brand itself on what is Zepbound.

The patent dates

The Orange Book lists ten distinct patents against tirzepatide products. Grouped by expiry:

Three things in that table matter.

The molecule patent ends on 13 May 2036 — fourteen years to the day after Mounjaro's approval. Fourteen years after approval is the ceiling the patent-term restoration law places on a drug patent's remaining life (35 U.S.C. 156(c)(3)). The Orange Book records the expiry but not how it was reached, so we do not state that an extension produced it; the coincidence of dates is what the record shows.

The later patents are mostly not on the molecule. Only US 9,474,780 carries the drug-substance flag on every product; one 2039 patent, US 11,357,820, carries it on the six Mounjaro vials alone and as a drug-product patent elsewhere. The rest cover formulations, devices and methods of use, which a generic manufacturer can try to design around, challenge or wait out.

The two brands end on different dates. The latest patent listed against Zepbound expires on 22 July 2039; Mounjaro carries one more, to 30 December 2041. FDA's Paragraph IV list gives exactly those two dates as the "expiration date of last qualifying patent" for each brand.

The challenge file: 13 May 2026

This is the record almost nobody reports. FDA's Paragraph IV list shows when generic applications that challenge a listed patent were first submitted, and how many arrived that day. For tirzepatide:

FDA, Paragraph IV Patent Certifications list, as of 14 September 2026. One application can cover several strengths, so the counts are per row and must not be added together. FDA does not name the applicants on this list.

13 May 2026 was the earliest day any of these could have been filed. The regulation reads that for a new chemical entity "no person may submit" a generic application "for a period of 5 years from the date of approval of the first approved NDA, except that the … ANDA may be submitted after 4 years if it contains a certification of patent invalidity or noninfringement" (21 CFR 314.108(b)(2)). Mounjaro was approved on 13 May 2022. Four years later, to the day, at least a dozen applications arrived against the single-dose pens.

For comparison, the same list records seven applications against Ozempic's first pens, filed on 6 December 2021 — four years after Ozempic's December 2017 approval. The pattern is the same: in this class, generic makers file on the first permitted day. Ozempic's own dates are on when will Ozempic go generic.

What the dates allow — and what they do not

Putting the files and the regulation together gives a set of floors, not a forecast:

The 2029 row is arithmetic, and it is conditional: it applies only if Lilly sued the applicants within the statutory window, and a court ruling or a settlement can move entry in either direction. Neither lawsuit filings nor any settlement appear in the FDA files, so this page does not say whether either has happened. Nothing in the public record fixes a launch date. What it does show is that generic tirzepatide is no longer a distant, untested question: the challenges were filed in May 2026 and the process now runs through patent litigation.

The exclusivity file also carries shorter, later entries for each brand — Zepbound's last ends on 20 December 2027 (code I-958) and Mounjaro's on 19 December 2028 (code NPP). Those attach to specific later approvals and protect them, not the molecule; the compound patent outlasts every one of them.

Why this matters for cost — and its limits

A generic is the usual route by which a drug's price falls, and the liraglutide record shows how it plays out in this class: eleven generic liraglutide applications were approved from December 2024, eight against Victoza and three against Saxenda (the register is on which drugs are GLP-1s). Nothing similar can happen for tirzepatide before 2027 at the very earliest.

Until then, the price of tirzepatide is the price Lilly sets, through insurance, its savings programmes and its own pharmacy. Those routes are documented on the Zepbound savings card, LillyDirect and what Zepbound costs. Products sold online as "tirzepatide" outside those routes are not generics — they are compounded or unapproved, and the difference is set out on the compounded-versus-branded record.

What this page will not tell you

It does not name the generic applicants (FDA's list does not), predict the outcome of any patent case, or forecast a price. The Orange Book is republished monthly and the Paragraph IV list as filings change; a patent can be added, delisted or invalidated and a settlement can set a date years ahead of any expiry. The files used here are dated 11 and 14 September 2026 and were read on 4 October 2026.

Sources

FDA Orange Book data files (products.txt, patent.txt, exclusivity.txt), file date 11 September 2026, downloaded and parsed 4 October 2026 · FDA, Paragraph IV Patent Certifications (PPIV) list as of 14 September 2026, Excel version, read 4 October 2026 · 21 CFR 314.107 and 314.108 (eCFR, version of 1 September 2026) · 35 U.S.C. 156(c)(3).