A once-weekly injection makes a missed dose an easy mistake and an awkward one: the next dose is days away, and the question is whether the late one still belongs to this week or should be dropped. Each of the four US GLP-1 labels answers it, and they do not answer it the same way. This page sets the four rules side by side, reports the June 2026 change to the Wegovy restart wording that most summaries still quote in its older form, and works out how far drug levels fall during a gap, using the half-lives the labels themselves state (labels read 2026-10-20). It reports what the documents say; it does not say what anyone should do.
The time-of-day and day-change rules are covered on the GLP-1 injection timing page; the dose ladders are on the Wegovy dose chart and the Zepbound dose chart.
The four labels' rules, side by side
| Label (version read) | Missed-dose window | Past the window | Minimum gap between two doses | Two or more missed weeks |
|---|---|---|---|---|
| MOUNJARO (tirzepatide), effective 2026-07-29 | As soon as possible within 4 days (96 h) | Skip; next dose on the regular day | 3 days (72 h) | No rule stated |
| ZEPBOUND (tirzepatide), effective 2026-08-28 | As soon as possible within 4 days (96 h) | Skip; next dose on the regular day | 3 days (72 h) | No rule stated |
| OZEMPIC injection (semaglutide), effective 2026-07-30 | As soon as possible within 5 days | Skip; next dose on the regular day | 2 days (more than 48 h) | No rule stated |
| WEGOVY injection (semaglutide), published 2026-06-30 | Given only if the next dose is more than 2 days (48 h) away | Skip if the next dose is less than 2 days away | 2 days, stated in the Medication Guide (the day may change if the last dose was 2 or more days before) | Reinitiate escalation at a lower dosage |
| WEGOVY tablets; OZEMPIC/RYBELSUS tablets | Daily tablet | Skip; next tablet the following day | — | — |
Two things stand out. The tirzepatide and Ozempic rules count forward from the missed day; the Wegovy rule counts backward from the next one. For an ordinary weekly schedule they come out close — a Wegovy dose missed by up to 5 days still has more than 48 hours before the next — but the wording differs, and a summary that quotes "5 days" for Wegovy is quoting Ozempic. And only one label of the four says anything about a gap longer than a week.
The Wegovy restart wording changed in 2026
The WEGOVY injection label still listed on DailyMed under a repackager (A-S Medication Solutions, set f5e548d0, version of April 2024) states that after two or more consecutive missed doses, dosing is resumed "as scheduled or, if needed", escalation is reinitiated. The Novo Nordisk label published on 2026-06-30 (set ee06186f), the one that added the 7.2 mg WEGOVY HD dose and the tablets, replaced that with a single instruction: reinitiate dose escalation "at a lower dosage", citing the risk of gastrointestinal adverse reactions. The Medication Guide in the same document puts it as contacting the healthcare provider about how to restart.
Neither tirzepatide label has an equivalent sentence. That is an absence, not a permission: the MOUNJARO and ZEPBOUND labels state the 4-day window and the 72-hour gap and stop there. Nothing in them says what happens after two missed weeks, and this page does not fill the gap.
What a missed week does to drug levels
Both drugs are long-acting, which is why a weekly schedule works at all. The labels give the half-lives this site's pages already report: tirzepatide about 5 days on MOUNJARO and 5 to 6 days on ZEPBOUND (tirzepatide half-life), semaglutide about one week on every Novo Nordisk label (semaglutide half-life). In a one-compartment model — a simplification that ignores absorption, and a model, not a measurement — the level on the day a dose was due falls by the same fraction for every week without one.
| Weeks without a dose | Tirzepatide, 5-day half-life | Tirzepatide, 6-day half-life | Semaglutide, 7-day half-life |
|---|---|---|---|
| 1 missed dose (14 days after the last) | 37.9% of the usual pre-dose level | 44.5% | 50.0% |
| 2 missed doses (21 days) | 14.4% | 19.8% | 25.0% |
| 3 missed doses (28 days) | 5.4% | 8.8% | 12.5% |
The same arithmetic explains the windows. A tirzepatide dose given 4 days late follows a level that has fallen to 57.4% of the usual pre-dose figure at a 5-day half-life; an Ozempic dose 5 days late follows 61.0% at one week. And the minimum gaps keep two doses from stacking too closely: 72 hours after a tirzepatide dose, 66.0% of it is still present at 5 days' half-life; 48 hours after a semaglutide dose, 82.0%.
The restart rule on the Wegovy label reads more naturally against the table. After two missed weeks a quarter of the usual level remains, which is closer to the start of treatment than to steady state — and the label's stated reason for restarting lower is tolerability, not efficacy.
Compounded vials have no window
Compounded tirzepatide and semaglutide are not FDA-approved products, so they come with no approved labeling and no missed-dose rule of their own. FDA's statement on unapproved GLP-1 drugs, current as of 2026-10-01, does not address timing at all. The adverse events it describes "may be related to dosing errors" that "resulted from patients measuring and self-administering incorrect doses of the drug" and from health care professionals "miscalculating doses". The documented hazard with a vial is the amount drawn, which is what the tirzepatide units page and the mg to units page work through.
What the half-life arithmetic says applies to the molecule, not the product: a vial of tirzepatide is cleared at the same rate as a pen. What it cannot supply is a rule. The 4-day and 5-day windows belong to specific labels; the vial arithmetic for any amount is in the tirzepatide calculator.
What this page does not do
It does not say whether a late dose should be given, how a schedule should be rebuilt, or at what dose anyone should restart. It reports each label's wording with its version and date and works the decay arithmetic from the labels' own half-lives. Medibact's tirzepatide guide and semaglutide guide cover the compounds; the injection procedure is on the tirzepatide injection page. Decisions about a missed or restarted dose belong with the prescriber.
Sources and dates
Opened 2026-10-20: openFDA drug label records for MOUNJARO (effective 2026-07-29), ZEPBOUND (effective 2026-08-28), OZEMPIC injection (effective 2026-07-30) and the OZEMPIC/RYBELSUS tablets (effective 2026-01-30), sections 2 and 10; DailyMed SPL ee06186f-2aa3-4990-a760-757579d8f77b (WEGOVY injection and tablets, Novo Nordisk, published 2026-06-30; section 2.4 and the Medication Guide) and f5e548d0-cc79-4c34-a3f5-e20a5b8b6564 (WEGOVY, A-S Medication Solutions, April 2024); FDA, "FDA's concerns with unapproved GLP-1 drugs used for weight loss" (content current as of 2026-10-01). Half-lives from this site's half-life pages (labels read 2026-09-25 and 2026-09-26). Decay and level arithmetic by this site. Corrections go to the contact page.