What Happens If You Miss a GLP-1 Shot? (October 2026)

01 · Your next step

What to do if you miss a GLP-1 shot

First, work out which medicine you use and how long ago the dose was due. For Mounjaro (tirzepatide), if you miss a dose, take it as soon as you can within 4 days (96 hours) of the scheduled time, then carry on with your usual day. ¹

If more than 4 days have passed, skip the missed dose entirely and take the next one on your normal day — never take two doses within 3 days of each other. ¹³ Do not try to make up for the lost dose by injecting extra.

02 · Planning

Do you need to change anything?

For most people the answer is no. Take the dose if you are inside the window, or skip it and carry on. If you keep forgetting your day, it may be worth moving it. You can change your weekly injection day if needed, as long as at least 3 days (72 hours) have passed since your last dose.¹

If you are being treated with us, our team can help with dose questions. If you are considering treatment, see the Mounjaro pen prices and consultation page, or our wider weight loss clinic information.

03 · What happens in your body

What happens in your body when you miss a shot

Your appetite control may gradually weaken as the medicine in your system slowly falls. Tirzepatide activates two gut-hormone receptors, GIP and GLP-1, which help regulate appetite, slow how quickly the stomach empties and improve the way the body responds to insulin.¹

With a late or skipped dose, you may notice more hunger between meals, stronger cravings and less of that early fullness.

The medicine also leaves your body slowly. Mounjaro takes roughly four to five weeks to clear after a final dose, so one missed shot does not mean the medicine has gone.¹

04 · Other GLP-1 medicines

Ozempic, Wegovy and other GLP-1 medicines

Each GLP-1 product has its own missed-dose instruction, and you should not assume Mounjaro's rule applies to another medicine.

For Wegovy, read the patient leaflet and the product information.¹⁸ For Ozempic, Saxenda or other products, use your leaflet or ask your pharmacist or prescriber. Ozempic is semaglutide licensed for type 2 diabetes. It is not a UK weight-loss medicine, and prescribing it privately for weight loss is off-label.

If you are weighing up a switch, our Wegovy pen page explains that option.

05 · Longer gaps

Missing several doses or a longer break

A longer gap needs a conversation, not guesswork.

We cover this in more detail in our guides on missing a week of Mounjaro, missing two weeks and whether you can skip two weeks.

Do not shortcut it by taking smaller or spread-out doses.

06 · Holidays and travel

Skipping a shot for a holiday

You rarely need to skip a shot for a holiday, because you can travel with your pen. You can fly with Mounjaro: carry pens in hand luggage, as hold luggage can fall below freezing, ideally in a cool bag with the prescription label or a copy of your prescription.¹³

Once in use, a pen can be kept out of the fridge at a temperature not above 30°C for up to 30 days after first use, and must then be thrown away.¹ Most holidays need no special arrangements, though hot climates call for an insulated pouch.

Check destination rules for travelling with prescription injectables before you fly. If a holiday means your usual day is awkward, changing day is possible within the rule above.

07 · Avoiding missed doses

How to avoid missing a shot

The simplest fix is routine. There is no best time of day: Mounjaro works the same morning or evening, with or without food, so what matters is the same day each week.¹ Many people choose a weekend morning so early side effects fall on days off.

Set a recurring phone alarm and keep your pen somewhere you will see it. A tracking app helps too; our free GLPTrackr companion app is available for iOS and Android. Each KwikPen contains four weekly doses, so it can also help to note when a pen is nearly finished and reorder in good time. Repeat orders re-check suitability, and we do not auto-ship.

A late delivery can also cause a gap, so see what happens if you miss your Mounjaro delivery.

08 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹