If you are switching to Wegovy from Mounjaro, Ozempic, or another GLP 1 medicine, you may come across online guides that suggest calculating your dose by counting pen clicks. However, there is no verified, manufacturer approved formula for converting Wegovy pen clicks into a specific dose. The Wegovy instructions tell you to use the dose shown on the pen and not to set or judge your dose by counting clicks.
This is particularly important when switching between medicines. Your Wegovy starting dose is not simply calculated from the dose of your previous medicine. Your prescriber will consider your treatment history and individual circumstances when deciding how and when to start Wegovy.
This page explains why click counting is not a reliable way to calculate a Wegovy dose and what a clinical switch between GLP 1 medicines may involve.
Key things to know
- Official Wegovy product information advises against setting or judging your dose by counting audible clicks
- There is no reliable, manufacturer verified "clicks per mg" conversion for Wegovy
- Any specific click count figures you see online should not be treated as official dosing guidance
- Switching from Mounjaro, Ozempic or another GLP 1 medicine to Wegovy is not a mg for mg calculation
- Your Wegovy starting dose should be decided by your prescriber based on your individual circumstances
- If you need a different Wegovy dose, you should use the pen prescribed for that dose rather than trying to adjust your current pen by counting clicks
What the Click on Your Wegovy Pen Actually Means
Standard Wegovy FlexTouch pens supplied in the UK are pre filled, multi dose pens with a specific strength, such as 0.25mg, 0.5mg, 1mg, 1.7mg or 2.4mg. The pen has a dose counter and dose selector that are used according to the instructions supplied with the pen.
The click you hear while using the pen is not a measurement that you should use to calculate a different dose. The official instructions explain how to select and give the prescribed dose. You should follow these instructions rather than trying to work out a dose from the number of clicks.
Wegovy FlexTouch pens contain 4 doses of the labelled strength. Each injection should be given using the prescribed dose and the correct instructions for your specific pen.
Why Switching Is Not a Click Calculation or a Dose Conversion Formula
If you are switching to Wegovy (semaglutide) from Mounjaro (tirzepatide), it is important to understand that these medicines contain different active ingredients and work in different ways. There is no established mg for mg conversion between tirzepatide and semaglutide.
Your appropriate Wegovy starting dose depends on factors such as your previous treatment, current dose, response, tolerability and other relevant health information. Your prescriber can use this information to decide where to start and how to manage your treatment.
The same principle applies when switching from Ozempic. Although Ozempic and Wegovy both contain semaglutide, they have different licensed uses and dosing schedules. A switch should therefore be discussed with your prescriber rather than treated as a simple dose for dose swap.
Why Counting Clicks to Calculate a Dose Is Not Recommended
- Click counts are not a validated method for measuring the amount of medicine in a Wegovy pen
- Trying to use clicks to create a smaller or different dose can result in you receiving an amount that is different from the dose prescribed for you
- It can make it harder for your prescriber to know exactly how much medicine you are taking
- It is not the way the pen is intended to be used or the way the prescribed dose is identified
- Online click charts or calculators are not a substitute for the dosing instructions supplied with your pen
Wegovy pens are designed to deliver the labelled dose selected according to the product instructions. They are not intended to be used as a DIY method for micro dosing or converting one GLP 1 medicine into another.
If you are unsure how to select or use your dose, speak to your pharmacist or prescriber before injecting.
What a Genuine Switch Involves
Switching between GLP 1 medicines involves more than comparing the numbers on two medicine pens.
Your prescriber may review your current medicine, dose, how long you have been taking it, how you have responded to treatment, any side effects and other medicines you take. They can then decide whether Wegovy is appropriate and what starting dose and timing may be suitable for you.
The timing of your first Wegovy dose can also matter when changing from another medicine. Your prescriber can advise you on when to start based on your treatment history.
People may consider changing medicines for different reasons. These can include side effects, cost, availability or a preference for another treatment. Whatever your reason, it is worth discussing it with your prescriber so that any change can be planned around your individual circumstances.
Why Semaglutide and Tirzepatide Are Not Interchangeable by Formula
Semaglutide, the active ingredient in Wegovy and Ozempic, is a GLP 1 receptor agonist. Tirzepatide, the active ingredient in Mounjaro, acts on both GIP and GLP 1 receptors.
Because these medicines have different active ingredients and different dosing schedules, there is no established clinical formula that converts a specific tirzepatide dose into an equivalent semaglutide dose, or vice versa.
This means that a previous dose of Mounjaro should not be used to calculate a Wegovy dose. Your prescriber should decide the appropriate starting point based on your individual circumstances.
The Wegovy Dose Escalation Schedule
| Weeks | Dose |
|---|---|
| 1-4 | 0.25mg |
| 5-8 | 0.5mg |
| 9-12 | 1mg |
| 13-16 | 1.7mg |
| 17 onwards | 2.4mg (maintenance) |
This is the standard Wegovy dose escalation schedule for adults starting treatment. Wegovy is usually started at 0.25mg once a week, with the dose increased every 4 weeks.
The gradual increase is intended to help the body adjust to treatment. Not everyone will follow the schedule in exactly the same way. Your prescriber may recommend delaying an increase or using a different approach depending on how you respond to treatment and whether you experience side effects.
If you are switching from another GLP 1 medicine, do not assume that you should simply start at the dose you were taking with your previous medicine. Your prescriber can advise you on the most appropriate starting point.
Why Cost Comparisons Between Providers Can Be Hard to Verify
You may see Wegovy click calculators or online dosing charts that also claim to show potential savings by using smaller amounts of medicine or making a pen last longer.
Specific savings figures, such as claims of saving over $500 or $800 per year, can be difficult to verify and may depend on factors such as the provider, medicine strength, treatment plan and how the medicine is being used.
Cost can be a reasonable factor to discuss when choosing a treatment, but it should not be used as a reason to change your dose or use a pen differently from its instructions. If cost is a concern, speak to your prescriber about the options available to you.
Common Side Effects When Switching
Wegovy can cause gastrointestinal side effects such as nausea, diarrhoea, constipation, vomiting and stomach discomfort. These effects may be more noticeable when starting treatment or increasing the dose. If you are switching from another GLP 1 medicine, you may still experience side effects even if you previously tolerated your other medicine well.
If side effects are difficult to manage or are affecting your daily activities, speak to your prescriber or pharmacist. They can advise whether your treatment needs to be reviewed.
Severe or persistent abdominal pain needs urgent medical attention because it can be a sign of a serious condition, including pancreatitis. Do not try to manage severe symptoms by changing your dose yourself.
Storing and Using Your Wegovy Pen
Store unopened Wegovy pens in the fridge at 2 to 8°C. Do not freeze the pen or place it next to a freezer compartment.
Once a pen is in use, storage instructions can depend on the specific Wegovy product and pen strength. Check your patient information leaflet for the exact storage period and temperature for your pen.
Before using the pen, check the medicine according to the instructions supplied with it. Do not use it if the solution does not look as described in the product information.
Always follow the instructions supplied with your specific Wegovy pen. If you are unsure how to use it, ask your pharmacist or prescriber for help.
Getting Started with EverydayMeds
Whether you are starting Wegovy for the first time or discussing a switch from another GLP 1 medicine, treatment begins with a free online clinical consultation. Your information is reviewed by our UK registered prescribing team, who can assess your individual circumstances and determine whether treatment is suitable for you.
Our team can also provide support if you have questions about switching medicines, dose timing or how to use your prescribed pen.
All treatment is dispensed by our GPhC registered pharmacy in compliance with MHRA regulations.
Medical Disclaimer
This page provides general information about Wegovy pen use and switching between GLP 1 medicines.
A Wegovy click calculator may ask you to enter information about your pen and then provide an estimated dose based on the number of clicks. However, this does not make the calculation an official dosing method or personalised medical advice.
Do not determine your Wegovy dose by counting clicks or try to convert your dose from another medicine yourself. Always follow the instructions supplied with your prescribed pen and speak to your prescriber or pharmacist before making any change to your treatment.
