What is Wegovy (Semaglutide) weight loss injections?

Dr Babak Ashrafi

Medically reviewed by

Dr Babak Ashrafi

Last reviewed: 14 Aug 2023

Wegovy is a prescription weight loss treatment that will be available to order online from ZAVA soon. It can help reduce your appetite, making it easier to lose weight as part of a diet and exercise plan.

Dr. Babak Ashrafi

“Wegovy is a medication adapted from an existing weight loss treatment, Ozempic (semaglutide). It’s useful for people who need help losing weight as part of an overall weight management plan. It’s approved for use in Ireland, but not available just yet as the manufacturers need more time to get it ready. We’re ready to add Wegovy to our weight loss service as soon as we can.”

Dr Babak Ashrafi, Clinical Lead for Service Expansion at ZAVA

What is Wegovy


  • is a weight loss treatment
  • works by reducing your appetite to stop you from overeating
  • is an injection used once a week
  • is a prescription-only medication
  • is for people with a BMI of over 30, or over 27 in some cases
  • is effective in over 80% of users
  • can lead to weight loss of over 20%
  • is safe to use if prescribed by a doctor
  • is coming to Ireland soon

Wegovy is a prescription-only weight loss injection treatment for people who are overweight. The active ingredient in Wegovy is a man-made hormone called semaglutide. It works by reducing your appetite like your hormones do naturally, making weight loss easier as you less hungry while you diet.

Who it’s for

Wegovy is a weight loss treatment for people who are overweight. This means someone who has a BMI of over 30, or over 27 if they have a weight-related health problem. A doctor can’t prescribe it to someone who doesn’t meet these criteria, even if they want to lose weight anyway.

Can I get it without a prescription?

No. Wegovy is a prescription medication because a doctor needs to make sure it’s safe and likely to be effective for you to use. You can’t get it over-the-counter or buy it online legally without a doctor being involved.

Once Wegovy is available in Ireland, ZAVA can help you find out if you can be prescribed Wegovy by doing an assessment when you place your order.

No results found.

No results found.
Please check your spelling or try another treatment name.

How to use it

It only needs to be used once a week for it to be effective and works best as part of a weight loss plan that includes diet and exercise. If you’re prescribed Wegovy, you’ll start on a lower dose for your first month and it will be increased each month afterwards, until month 5 of your treatment (see available dosages section below for more details).

How to take a dose

Before starting treatment, carefully read the instructions in the patient information leaflet that comes with Wegovy and follow any instructions from your doctor. When you’re ready to try your first dose, follow the steps below:

  1. Wash your hands.
  2. Decide on where you want to inject your first dose. You can choose from your lower abdomen, thigh, or upper arm. Once you’ve decided, wash the area you’re going to inject with an alcohol swab or soap and water.
  3. Remove the pen cap. Only do this once you’re ready to do your injection.
  4. Push the pen cap against your skin and keep pressing until the yellow bar has stopped moving. If the yellow bar doesn’t move, push harder.
  5. Safely throw away your used Wegovy pen.

Some extra advice:

  • Store your injections in the fridge.
  • Check your pen before using it in case it’s been broken.
  • 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 it over a longer period of time and 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 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.

How Wegovy works

The active ingredient in Wegovy is semaglutide. Semaglutide is an artificial version of something your body already uses to manage appetite. It works by reducing your appetite, just like your body naturally does after you’ve eaten. This is how Wegovy helps you feel full after eating less food than normal and helps you avoid overeating or snacking, making it easier to stick to your diet plan.

How quickly can you see results?

After you start 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 don’t see any change after 6 weeks, you might want to think about changing treatment to an alternative like Saxenda or Ozempic.

Available dosages

There are 5 different doses of Wegovy:

  • 0.25mg
  • 0.5mg
  • 1mg
  • 1.7mg
  • 2.4mg

You’ll be started on the lowest dose in the first month and move up 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. Wegovy is an effective treatment at the normal doses listed above, when used properly.

If you are prescribed Wegovy, your doctor will give you clear instructions on how to get the best safest treatment possible. Wegovy can take up to 2 months to leave your system completely after your last dose.

How effective is Wegovy?

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.

We know this is true because of a 68-week long study done on patients using Wegovy. Compared to people just using a placebo (taking injections that don’t actually have medication in), this study showed that:

  • 86% lost at least 5% weight
  • 69% lost at least 10% weight
  • 50% lost at least 15% weight

What are reviews of Wegovy like?

Wegovy is rated:

Weight loss treatment comparison


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. 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 is another name for semaglutide, but it is not licensed for weight loss. Wegovy is meant 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 0.5mg, 1mg, or 2mg doses.

Other medical weight loss treatments

Other options to think about are:

  • Mysimba (Tablets), similar to Wegovy and Saxenda, it reduces appetite as well
  • Xenical (Tablets), a medication that stops your body from absorbing fat that you eat (Tablets)
  • Orlistat (Tablets), the generic version of Xenical which works in the same way but cost less because it’s not branded (Tablets)
  • Alli, a version of orlistat (Tablets)
  • Weight loss surgeries, like stomach stapling
No results found.

No results found.
Please check your spelling or try another treatment name.

Other weight loss options

Weight loss options that don’t include medical treatments are always a good idea, and they usually can (and should) be used alongside any medical weight loss treatments you’re on. These can include:

  • dieting
  • exercising more
  • joining weight loss groups

Safety information

Wegovy should be safe for you to take as long as a doctor has prescribed it for you. Wegovy isn’t right for everyone, which is why a doctor won’t prescribe certain treatments if:

  • you’re pregnant or planning to get pregnant
  • you’re seriously allergic to any of Wegovy’s ingredients
  • you have a family history of MTC thyroid cancer (medullary thyroid carcinoma)
  • you have multiple endocrine neoplasia syndrome type 2

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

All of these questions will be covered in ZAVA’s online assessment for Wegovy treatment when it’s available.

Possible side effects

Like any medication, Wegovy can cause side effects in some people.

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

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.

Frequently asked questions

Is it available now in Ireland?

Not yet, but hopefully soon. Wegovy is not currently available in Ireland but Novo Nordisk, the manufacturer, is working to make it available soon.

Where can you buy it?

Once Wegovy is available in Ireland and you have a prescription, you should be able to get it filled at most pharmacies. You will also be able to buy Wegovy online using an online doctor service, like ZAVA.

How much does it cost?

As it hasn’t been made available yet in Ireland, we can’t provide a price. Please check back often, as we will publish pricing information as soon as we have it.

Is it available on the NHS?

It isn’t available yet, but it has been approved for NHS weight loss treatment, so it should be provided once it’s supplied to Ireland. Although, it is likely that, like Saxenda, Wegovy will be only be prescribed by a weight management specialist if:

  • you’ve tried weight loss without medication first
  • you’ve tried treatments like orlistat first
  • weight loss surgery isn’t possible for you
  • you’ve a BMI of between 30 kg/m² and 35 kg/m² and a health problem that can affect your weight, such as diabetes
  • you’ve BMI of 35 kg/m² or more, even if you do not have a weight related medical condition

Is it available with a private prescription?

Not yet, but once it’s supplied to Ireland, it should be possible to get a private prescription for Wegovy. Whether you can get it on private health insurance will depend on your insurance provider. ZAVA will be able to offer Wegovy through its online doctor service when it’s ready for Ireland.

What happens when you stop using Wegovy?

Shortly after you stop your Wegovy treatment, your appetite will increase back to normal levels. This is important to keep in mind when you’re trying 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.

Medically reviewed by:
Dr Babak Ashrafi Clinical Lead for Service Expansion

Babak studied medicine at King’s College London and graduated in 2003, having also gained a bachelor’s degree in Physiology during his time there. He completed his general practice (GP) training in East London, where he worked for a number of years as a partner at a large inner-city GP practice. He completed the Royal College of GPs membership exam in 2007.

Meet our doctors

Article created: 14 Aug 2023

Last reviewed: 14 Aug 2023

Our Service