Jabwise

Your first weeks on a GLP-1

Every leaflet and label here starts on a low dose for about a month before the first step up. Mounjaro’s says feeling sick, diarrhoea and being sick are most common when first starting, and decrease over time in most patients. Wegovy’s and Ozempic’s say learn the pen from your doctor or nurse first.

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Starting doses

Each source’s first dose, quoted as written. Rybelsus’s older tablets start on 3mg and its newer ones on 1.5mg, each for one month before the first step up.

MedicineStarts on
MounjaroThe starting dose is 2.5 mg once a week for four weeks.Mounjaro KwikPen patient leaflet
ZepboundThe recommended starting dosage is 2.5 mg injected subcutaneously once weekly for 4 weeks.Zepbound prescribing information
WegovyWhen you first start using wegovy®, the starting dose is 0.25 mg once weekly.Wegovy FlexTouch patient leaflet
OzempicThe starting dose is 0.25 mg once a week for four weeks.Ozempic patient leaflet
RybelsusThe starting dose is one 3 mg tablet once a day for one month.Rybelsus 3, 7 and 14mg patient leaflet

Early on

  • Stomach side effects

    Mounjaro’s leaflet says feeling sick, diarrhoea and being sick are most common at first, then ease in most patients.

  • Fluids

    When starting Mounjaro, its leaflet says, some people lose fluids; it says drink plenty of fluids to avoid dehydration.

  • Dizziness

    Wegovy’s leaflet says some people feel dizzy, mainly in the first 3 months, and not to drive until they feel better.

  • Contraception

    On tirzepatide, the NHS says use extra barrier contraception, like condoms, for 4 weeks after starting and each increase.

Before the first jab

  • Learning the penWegovy’s and Ozempic’s leaflets say your doctor or nurse will show you, or to ask them.
  • What to raise firstThe leaflets list things to tell your doctor first, such as pancreatitis or a slow-emptying stomach.
  • The same day each weekMounjaro, Wegovy and Ozempic ask for the same day each week, where you can.
  • New pens in the fridgeMounjaro’s, Wegovy’s and Ozempic’s leaflets say keep new pens in the fridge, at 2 to 8°C, never frozen.

Questions

Will the side effects last?

Mounjaro’s leaflet says feeling sick, diarrhoea and being sick decrease over time in most patients, and Ozempic’s says feeling sick and diarrhoea usually go away. None gives a timescale.

How long until the level settles?

Mounjaro’s product information says after 4 weeks of weekly doses, and Ozempic’s says 4 to 5. Our guide to how a weekly jab builds up shows it.

What if I miss a dose?

Mounjaro’s leaflet and Zepbound’s label say use it within 4 days, Wegovy’s and Ozempic’s within 5, and otherwise skip it. None covers a missed first dose; your prescriber can advise.

Mood trends

See how your first weeks feel.

Check in morning, afternoon or evening. Mood shows the answer you log most over 7, 30 or 90 days, and once one part of the day leads, when you feel best.

Jabwise Mood: Good is the most logged answer over 30 days, usually best in the evening

Sources

General information, not medical advice. Follow your prescriber’s guidance.

Getting real advice

We’re not doctors. This page sums up what the NHS and the official medicine information say, and can’t tell you what’s right for your body: your prescriber’s instructions and the leaflet in your box come first. More in our terms.

  • Quoted from official sources, each one linked
  • Sources checked 12 October 2026
  • No dosing advice; your prescriber comes first