GLP-1 tool guide
GLP-1 pen calculator: how long will my pens last and what do they cost?
Written by Harshita Sharma · Reviewed by Dr Himani Nayyar, BHMS · Updated
For people already prescribed GLP-1 medication. Weight Easy does not prescribe, sell or arrange medication; your prescriber is responsible for treatment decisions.
In brief
A multi-dose GLP-1 pen such as the Mounjaro KwikPen or Wegovy FlexTouch holds 4 weekly doses, so one pen lasts 4 weeks. Single-dose pens and vials last 1 week each. Add your doses left and unopened pens to see your run-out date, when to reorder, and your cost per dose, month and year.
Open the free GLP-1 Pen Supply & Cost Calculator →How many doses are in a GLP-1 pen?
It depends on the pen and the country. Always check the box or leaflet, but these are the common formats:
- Mounjaro KwikPen (UK, EU, India and others): 4 weekly doses of one strength.
- Wegovy FlexTouch (UK and EU): 4 weekly doses of one strength.
- Mounjaro and Zepbound single-dose pens and Zepbound vials (US): 1 dose each, usually sold as a 4-pack.
- Wegovy single-dose pens (US): 1 dose each, sold as a 4-pack.
- Ozempic, generic semaglutide (Obeda, Noveltreat, Semaglyn and others) and Yurpeak pens: doses vary by strength, so check the label.
- Trulicity and Bydureon BCise: single-dose pens, 1 per week.
- Saxenda, Victoza and Byetta: daily multi-dose pens; how long one lasts depends on your dose.
- Rybelsus, Wegovy pill and Foundayo: daily tablets; count tablets per pack instead of pens.
Plan your reorder before you run out
Prescriptions, pharmacy stock and delivery can each take days. Missing doses, especially two or more weekly doses in a row, can mean restarting at a lower dose and dealing with side effects again, so reorder at least a week before your last dose.
What GLP-1s cost per month
Your monthly cost is the price per pen divided by doses per pen, times about 4.3 weekly doses a month. Prices change often and differ between pharmacies and countries, so enter what you actually pay. In India, generic semaglutide launched after the patent expired in March 2026, at a fraction of the branded price; compare brands with your doctor before switching.
Don't stretch a pen
Counting clicks or drawing extra doses out of a pen is not part of the label, can give the wrong dose, and can be unsafe. If cost is the problem, ask your prescriber about options such as a different strength, brand or supply route.
Frequently asked questions
FAQ
How many doses are in a Mounjaro KwikPen?
Each Mounjaro KwikPen holds 4 weekly doses of a single strength, so one pen lasts 4 weeks. The instructions say not to use any medicine left in the pen after the fourth dose.
How long does a Wegovy pen last?
A Wegovy FlexTouch pen (UK, EU) holds 4 weekly doses and lasts 4 weeks. US Wegovy pens are single-dose, so one pen covers one week.
When should I reorder my GLP-1 pens?
At least 7 days before your last dose, or longer if your pharmacy or prescription takes more time. The calculator gives you the exact date.
How much does Mounjaro cost per month?
Divide the price per pen by 4 doses, then multiply by about 4.3 weeks. Enter your own pen price above to see your cost per dose, month and year in your currency.
Can I use leftover medication in my pen?
No. Use only the doses the label says the pen delivers. Leftover liquid is there so each dose is accurate.
Sources and limits
- Mounjaro KwikPen, Wegovy FlexTouch, Zepbound and Wegovy single-dose pen instructions for use.
- Cost figures are calculated from the price you enter; we don't store it.
This guide is educational, not a diagnosis, prescription or dose-change instruction. Always follow your medication leaflet and clinician.