Wegovy
Injectable prescription weight loss medication that works by reducing your appetite

Wegovy is a prescription weight loss treatment. It can help reduce your appetite, making it easier to lose weight as part of a diet and exercise plan. The weekly injection is self-administered and only suitable for overweight patients (BMI over 30 or BMI over 27 with weight-related health issues). Wegovy is produced by the danish company Novo Nordisk.



About Wegovy
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Wegovy:
- is for people with a BMI of over 30, or over 27 in some cases
- works by reducing your appetite and stopping you from overeating
- is effective in over 80% of users
- can lead to weight loss of over 20%
- is safe to use if prescribed by a doctor
Wegovy is a prescription-only injection used for weight loss. You take it once a week and it is safe to use long-term.
The active ingredient in Wegovy is semaglutide. Semaglutide is an artificial version of a hormone your body already produces to manage appetite.
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You can get a consultation and prescription for Wegovy online in Ireland from regulated online doctor services like ZAVA. Our doctors provide consultations and prescriptions for weight loss treatments, supported with diet and exercise plans, to help you safely and effectively lose weight.
Can I get Wegovy over the counter?
No, you cannot get Wegovy over the counter. Wegovy is a prescription medication, which means a doctor needs to check that treatment will be safe and appropriate for you.
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Wegovy works by reducing your appetite, just like your body naturally does after you’ve eaten. By doing so, Wegovy helps you feel fuller after eating less food than normal to stop you overeating or snacking, making it easier to stick to a diet plan.
How quickly can you see results?
After you start your treatment, you should feel fuller after eating by the second or third dose. But since people react differently to medications, it might work slightly faster or slower for you. If you have not lost significant weight after 6 months, you should think about changing treatment.
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Wegovy works for the majority of people who use it. Over 80% of Wegovy users can expect to see extra weight loss beyond what they would have achieved without it. You could lose 20% or more weight on this treatment.
A 68-week long study compared people taking Wegovy to a placebo and it showed that:
- 86% lost at least 5% weight
- 69% lost at least 10% weight
- 50% lost at least 15% weight
A different study comparing semaglutide (Wegovy) and liraglutide (Saxenda) found that 37.4% of pateints lost a minimum of 20% of their starting weight after 68 weeks when taking the 2.4mg dosage.
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There are five different doses of Wegovy:
- 0.25mg
- 0.5mg
- 1mg
- 1.7mg
- 2.4mg
Your doctor will supervise your treatment with Wegovy on the lowest dose in the first month and move up, if needed, to the highest dose after 5 months. Each dose step takes at least 4 weeks before moving on to the next one.
A doctor can’t prescribe more Wegovy than is safe to use, so there aren’t higher doses to choose from.
If you are prescribed Wegovy, your doctor will give you clear instructions on how to get the best effect and the safest treatment possible.
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Saxenda
Saxenda works in almost exactly the same way as Wegovy. The only real difference is the active ingredient in Saxenda is another artificial hormone, liraglutide, and is taken once a day. But, both medications still work the same way, which is by reducing your appetite.
You could try either Wegovy or Saxenda first. If you don’t find the treatment is working for you after six weeks, you could think about switching. People react differently to different medications so even though they’re similar, one could work when the other doesn’t. It’s impossible to tell which will work for you, so the only way to know for sure is by trying them out.
Don’t ever take these medications together. If you want to switch from one to the other, get a doctor involved who can help you plan the switch so you don’t end up with both medications in your system at the same time. When switching from semaglutide (Wegovy or Ozempic) to Saxenda, you need to wait 2 months from the time of your last dose before you can start Saxenda. This is to reduce your risk of side effects.
Ozempic
Ozempic is another name for semaglutide (the active ingredient in Wegovy). Wegovy is prescribed for patients with or without diabetes for weight loss but Ozempic is only meant to treat people for type 2 diabetes. The active ingredient in both medications is the same, but the dosages can be different. Ozempic is available in 0.25mg, 0.5mg, or 1mg doses.
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You need to take Wegovy once a week for it to be effective and it works best as part of a weight loss plan that includes a healthy diet and exercise as well. If you’re prescribed Wegovy, you’ll be started on a lower dose in your first month and your dose will be increased each month afterwards, until month 5 of your treatment.
How to take a dose
Before starting treatment, carefully read the instructions in the patient information leaflet that comes with your Wegovy and follow any instructions from your doctor as well. When you’re ready to try your first dose, follow the steps below:
- Check your pen is safe to use. You can see the Wegovy injection liquid through the pen window, check that Wegovy is clear and doesn’t have a colour. If it’s not, use a new pen. You also need a new needle for each injection. Check the needle for signs of damage and dispose if unsealed or bent.
- Wash your hands with lukewarm water and soap. Use an alcohol wipe to clean the area you will be injecting (abdomen, upper legs, or upper arms).
- Attach the needle to your pen, take its cap off and put it aside for later. Then, check the flow by turning the dose selector to flow check (two dots and a line). Point the needle up and press the dose button until it hits 0. You should then see a small amount of medication at the tip. This shows that it is read to use. If this doesn't work try a new needle or pen.
- Set your dose, ensuring the lines match up with the dose pointer.
- Remove the inner cap on the needle and save the outer cap for later. Make sure you can see the dose window when you inject then insert the needle into your injection site, hold the button down until it reaches 0 and count to 6 before removing. You should hear a click when the injection starts and also during.
- Once you have injected, safely remove the pen from your skin and a small drop of medication may be released from the tip of the needle, this is normal. Then, gently press the area with a cotton pad or tissue if ou have bled. Safely get rid of the needle by attaching the needle cap you saved from before. Dispose of your needle in a sharps bin, and safely store your Wegovy pen.
Some extra advice:
- Store your injections in the fridge.
- Check your pen before using it in case it’s been broken, like if it’s been dropped.
- Avoid injecting into areas that are bruised, sore, hard, or scarred. Also, be careful not to inject into your muscles or veins.
- Don’t touch the needle cover to avoid accidentally pricking yourself.
- Don’t try and stop the injection halfway through because the needle locks once it starts.
- Make sure you switch up where you inject your Wegovy after each dose.
Missing doses
If you miss a dose by less than 5 days, you can take that dose, and then your next one will be a week after this delayed dose.
If you miss a dose and it’s more than 5 days, then wait (i.e. skip this dose) and take your next dose on the usual day, at the usual time.
If you want to change the day of the week you use Wegovy to better suit your needs, you can do so as long as there is more than 3 days between doses.
If the last dose you took was more than 2 weeks ago, you need to restart at the lowest strength dose of 0.25mg weekly, and start again.
Using it long-term
It’s fine to use Wegovy long-term to help you manage your weight. There are no extra side effects from using Wegovy as long as it is beneficial to you. There’s no risk of addiction when it comes to stopping your treatment. Be aware that your appetite will increase to normal levels once you stop using Wegovy, so you need to account for this in your plan to maintain your lower weight.
Drinking on Wegovy
Alcohol doesn’t react with Wegovy, but since they both lower your blood sugar you should watch out for dizziness. Plus, alcohol has a lot of extra calories and can increase your appetite for unhealthy foods, so if you can, try to drink less during treatment.
Driving on Wegovy
You can also drive on Wegovy, but it’s a good idea to pay attention to how you feel after your first few doses to make sure Wegovy doesn’t affect your ability to drive safely.
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Wegovy should be safe for you to take as long as a doctor has prescribed it for you.
Who can use Wegovy?
Wegovy isn’t right for everyone, which is a why a doctor won’t prescribe treatment if you:
- you’re pregnant or planning to get pregnant
- you’re seriously allergic to any of Wegovy’s ingredients
In order to make sure Wegovy is safe for you, a doctor will ask about:
- any pancreas or heart problems
- whether you’re pregnant, planning to become pregnant or breastfeeding
What are the side effects of Wegovy?
Very common side effects that affect more than 10% of users include:
- headache
- feeling sick
- throwing up
- diarrhoea
- constipation
- stomach pain
- feeling weak or tired
Common side effects that affect up to 10% of users include:
- dizziness
- stomach and digestion problems
- burping
- gas
- bloating
- inflamed stomach
- acid reflux
- gallstone
- hair loss
- reactions where the injection was used
- low blood sugar for people with diabetes
Uncommon side effects that affect up to 1% of users include:
- fast heartbeat
- increased pancreatic enzymes in blood tests
For full safety information on Wegovy, please see this medication guide.
Signs of serious side effects and what to do
Stop using Wegovy and contact a doctor if you experiences any of the following:
- severe stomach pain that doesn’t go away, even if you throw up
- signs of gallbladder problems, including pain in the upper abdomen, fever, yellow skin or eyes, or clay-coloured poo
- signs of low blood sugar, if you have type 2 diabetes, including dizziness or light-headedness, sweating, shakiness, blurred vision, slurred speech, weakness, anxiety, hunger, headache, feeling irritable or mood swings, confusion or drowsiness, fast heartbeat, or feeling jittery
- kidney problems
- changes to your eyesight, if you have type 2 diabetes
- increased heart rate
- depression or suicidal thoughts
For full safety information on Wegovy, please see this medication guide.
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Frequently asked questions
Is it available now in Ireland?
Yes. Wegovy is now available to request for a prescription.
How much does it cost?
As it hasn’t been made available yet in Ireland we can’t quote a price. Please check back often as we will publish pricing information as soon as we have it.
Is Wegovy the same as Ozempic?
Ozempic is another name for semaglutide, the same active ingredient that is in Wegovy. Wegovy is meant for patients with or without diabetes but Ozempic is only meant for people with type 2 diabetes. The active ingredient in both medications is the same, but the dosages can be different. Ozempic is available in 0.25mg, 0.5mg, or 1mg doses.
Is Wegovy stronger than Saxenda?
Neither treatment is ‘stronger’ than the other. Although, Wegovy tends to be more effective overall.
People using Wegovy have a:
- 86% chance of losing at least 5% weight
- 71% chance of losing at least 10% weight
- 56% chance of losing at least 15% weight
- 39% chance of losing at least 20% weight
People using Saxenda have a:
- 56% chance of losing at least 5% weight
- 26% chance of losing at least 10% weight
- 12% chance of losing at least 15% weight
- 6% chance of losing at least 20% weight
Does Wegovy burn fat?
No. Wegovy makes it easier to eat less food. When you eat less calories that you use during the day, your body burns fat to make up the difference.
Do you have to exercise on Wegovy?
Yes. Wegovy does not cause weight loss by itself, you need to combine it with a diet and exercise plan. Exercise can be a great way to improve weight loss and Wegovy can help you feel less hungry after you exercise.
Does Wegovy cause hair loss?
Hair loss is a possible side effect of Wegovy.
Some people can get temporary hair loss from losing weight, which is known as ‘telogen effluvium’. It usually goes away after about 6 months because your body adapts to your new weight.
Does Wegovy cause mood changes?
Wegovy would only cause mood swings if you’re experiencing low blood sugar as a side effect. Low blood sugar can be a serious side effect of Wegovy, so if you’re having mood swings or any other signs of low blood sugar, contact a doctor.
What happens when you stop using Wegovy?
Shortly after you stop your Wegovy treatment your appetite will increase back to normal levels. If you’re having any side effects, they should also go away after the Wegovy in your body is removed. Wegovy can take about up to 2 months to leave your system completely after your last dose.
Do you gain weight back after stopping Wegovy?
The fact that your appetite will come back when you stop Wegovy means you need to put in the effort to maintain your new weight. But, if you continue to stick to your diet and exercise plan you can avoid putting the weight back on.

Sophie has worked as a GP both in France and in the UK. She moved to online medicine in 2016 and finds this new way of practising very rewarding. Sophie appreciates how practical digital healthcare is for patients, and believes it's a very good way to address issues that can be embarrassing for patients to talk about in-person.
Meet our doctorsArticle created: 14 Aug 2023
Last reviewed: 28 Mar 2025
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https://www2.hse.ie/conditions/obesity/ [accessed April 2025]
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IMC-Number: 429637

IMC-Number: 425122