How does Ozempic Work for Weight Loss

Dr Crystal Wyllie

Medically reviewed by

Dr Crystal Wyllie

Last reviewed: 28 Jan 2025

Ozempic is an injectable medication designed to treat type 2 diabetes which can also be effective for weight loss.

This article will help you find out what you need to know about Ozempic for weight loss (when taken as a diabetic medication): how it works,how effective it is, its side effects, if it’s available to you, and if not, alternative medications that are available for weight loss.

Contents
 

What is Ozempic?

You may have heard about Ozempic for weight loss and might be wondering what it is.

Ozempic contains the active ingredient semaglutide, which mimics a hormone that tells your brain you feel full and works to suppress your appetite. For this reason, Ozempic has gained popularity as a weight loss treatment.

Despite this, Ozempic is not actually approved for weight loss in the UK, it is only licensed to treat those with type 2 diabetes. There is a medication with the same active ingredient that is approved for weight loss in the UK, called Wegovy.

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How does Ozempic work for weight loss?

Ozempic can work for weight loss because one of its effects is to reduce your appetite. This means it makes you feel fuller after eating less food, helping you to avoid snacking between meals, and as a result helping you lose weight. Ozempic also works to support weight loss by regulating blood sugar levels and slowing down digestion.

After eating, our bodies release a hormone called a glucagon-like peptide or a ‘GLP-1’. This hormone has several roles including stimulating insulin release, slowing the emptying of the stomach, and sending signals to the area of the brain that is responsible for feelings of hunger and fullness. Ozempic belongs to a class of medications called glucagon-like peptide-1 agonists meaning it is able to mimic the naturally occurring GLP-1 hormone, leading to weight loss in many cases.” — Dr Crystal Wyllie

Explore more information on the ways Ozempic works for weight loss and how it:

Decreases appetite

You may find that you want or need to eat less on Ozempic, which can result in weight loss. The GLP-1 hormone affects the areas of your brain that deal with feelings of hunger and fullness. Ozempic replicates this hormone helping to reduce hunger, making you feel fuller more quickly, and to also stay fuller for longer. Having a smaller appetite and feeling less hungry should make you eat less which can be very effective for weight loss, alongside following a healthy diet and regular exercise.

Regulates blood sugar

Ozempic is a treatment developed for type 2 diabetes, a condition where insulin production is lower than it should be. Ozempic helps to encourage the release of insulin from your pancreas when your body needs it. Improved insulin production while on Ozempic has a positive impact on the body and its metabolism which can also promote weight loss because it:

  • helps improve insulin sensitivity or ‘insulin resistance’. This term refers to how well your liver and fat cells are able to respond to insulin as they should and take glucose (sugar) from the blood. When insulin is released properly it lowers your blood sugar levels.
  • reduces glucose levels in the blood, which can indirectly impact fat storage because, when insulin resistance is improved, your body is able to use fat stores for energy, rather than for glucose.

Slows digestion

Ozempic can slow down how quickly the stomach digests and empties. This is because as a GLP-1 agonist, Ozempic reduces the amount of glucose (sugar) that the liver makes and slows digestion of food in the stomach.

In terms of weight loss, this means that glucose from the food you eat is released into the bloodstream more slowly, controlling blood sugar levels and making you feel full for longer. As a result, you should want to eat less which can contribute to weight loss.

How long does Ozempic take to work?

When taking Ozempic for weight loss, you may find your appetite is lower after your very first dose but it can take up to a few weeks to notice a difference. When it comes to actually losing weight, it can take longer to see results.

Wegovy is an effective medication for weight loss with the same active ingredient (semaglutide), unlike Ozempic, it is licensed for patient use for weight loss in the UK. Wegovy is an effective weight loss treatment, with clinical trials showing patients to lose at least 5% of their starting weight after taking the 2.4mg (maximum maintenance dosage) titrated over 28 weeks of treatment. If you have not lost at least 5% of your starting weight after 6 months, your doctor may suggest alternative treatment.

Weight loss on Ozempic may take longer than on Wegovy because Wegovy has a higher maximum dosage than Ozempic.

How long do you have to take Ozempic?

Semaglutide is meant to be used as a long-term weight loss treatment under the guidance of your doctor. When you have reached your weight loss goals, your doctor will recommend stopping treatment. However, to maintain your results you should aim to continue following a healthy diet with smaller portions alongside regular exercise.

Effectiveness of Ozempic for weight loss

The effectiveness of Ozempic for weight loss has gained lots of attention in recent years. It is true that Ozempic can result in weight loss, however, Ozempic is only licensed to treat people with type 2 diabetes in the UK, and it is not yet an approved treatment for weight loss.

The effectiveness of Ozempic for weight loss in type 2 diabetes

Studies show that on the highest dosage of Ozempic (1mg) after one year:

  • up to 62% of patients lost 5% or more of their starting weight
  • up to 24% of patients lost 10% or more of their starting weight

People with type 2 diabetes who take Ozempic to help regulate their blood sugar often also see weight loss because the treatment suppresses appetite and improves blood sugar control.

The effectiveness of Ozempic for weight loss with or without type 2 diabetes

Studies show that when taking semaglutide ( the active ingredient in Ozempic), is used by people with or without diabetes to support weight loss in the form of Wegovy:

  • 83.5% of patients lost 5% or more of their starting weight
  • 66.1% of patients lost 10% or more of their starting weight
  • 47.9% of patients lost 15% or more of their starting weight
  • 30.2% of patients lost 20% or more of their starting weight

Weight loss results are higher for patients taking Wegovy than for patients taking Ozempic for diabetes. This may be because Wegovy has a higher maximum dose than Ozempic, and because Wegovy is only licensed for people who are overweight whereas Ozempic can be used by people with diabetes who are not overweight.

Ozempic side effects

Ozempic, like all medications, can cause side effects. However, not everyone will experience side effects.

Ozempic’s most common side effects are usually mild and are not serious but they can be uncomfortable and unpleasant for some people. The majority of Ozempic side effects will get better and go away on their own as you adjust to taking the medication.

Serious side effects are uncommon or rare but they can potentially be life-threatening so you should be aware of them and signs of them.

If you do experience side effects that are serious or that are affecting your daily life, speak to your doctor about adjusting your dosage or changing treatments.

Common side effects of Ozempic

Very common side effects, which will affect more than 1 in 10 people taking Ozempic, include:

  • nausea (feeling sick)
  • diarrhoea

Other common side effects of Ozempic that may affect up to 1 in 10 people include:

  • constipation
  • nausea and vomiting (feeling or being sick)
  • dizziness
  • low blood sugar (hypoglycaemia), when Ozempic is used with other medications to lower blood sugar such as insulin
  • heartburn, reflux, or indigestion (gastrointestinal discomfort)
  • weight loss
  • tiredness
  • injection site itching or soreness

Serious side effects of Ozempic

Ozempic can have some serious side effects. These are uncommon or rare.

Serious Ozempic side effects include:

  • complications of diabetic eye disease (retinopathy), if you experience any changes in your vision or new eye problems while on Ozempic speak to your doctor
  • pancreatitis (this condition is an inflammation of the pancreas, it causes severe abdominal pain that does not go away)
  • a serious allergic reaction (anaphylaxis) signs of this include breathing difficulties (breathlessness or wheezing) or swelling of the mouth, throat, tongue, face or lips

You should seek medical help or advice if you experience any of these side effects. Speak to your doctor if you are concerned or call 111 or 999 in an emergency.

For further information on the side effects of Ozempic, consult the patient information leaflet online or the physical copy that comes with your medication.

Ozempic vs weight loss medications

Ozempic is not the only medication that can help with weight loss. There are medications that are approved to be used safely and specifically for weight loss in the UK that are just as effective as Ozempic.

There are a range of weight loss treatments available in both the oral tablet form and injections that are effective when taken alongside a balanced diet and regular exercise as directed by a doctor.

Here is an overview comparison of weight loss injections available at ASDA Online Doctor:

Weight loss injection comparison guide

Wegovy Mounjaro Liraglutide
Active ingredient Semaglutide Tirzepatide Liraglutide
Effectiveness People lost and maintained weight loss of up to 15% of their starting body weight on the highest dose of 2.4mg in 68 weeks People lost up to 22.5% of their starting body weight on the maintenance dose of 15mg in 52 weeks People lost up to around 8% of their starting body weight on the maintenance dose of 3mg in 56 weeks
Injected daily or weekly Weekly Weekly Daily
Dosages 0.25mg, 0.5mg, 1mg, 1.7mg, 2.4mg 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, 15mg 0.6mg, 1.2mg, 1.8mg, 2.4mg, 3mg
Most common side effects headache, nausea, vomiting, diarrhoea, constipation, stomach pain, tiredness low blood sugar, nausea, vomiting, diarrhoea constipation, stomach pain vomiting, nausea, diarrhoea, constipation, headache
Prescription or over-the-counter Prescription Prescription Prescription

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Weight loss tablets

Most weight loss tablets work differently to Ozempic. Tablets like Xenical, Orlistat and alli are taken orally, usually with food, and are most effective when used alongside diet and lifestyle changes. They work by stopping your body absorbing fat from food you eat.

Mysimba is more similar to Ozempic as it also reduces your appetite and the dosage is gradually increased over time. However, Mysimba’s active ingredients work in the brain to increase feelings of fullness, while Ozempic works mostly in the digestive system to achieve the same outcome.

Here is an overview of key information on weight loss tablets available at ASDA Online Doctor:

Orlistat and Xenical:

  • Prescription-only, oral 120mg tablet
  • Contains active ingredient orlistat
  • Works by preventing your body from absorbing fat from the food you eat
  • Must be taken up to 3 times a day with water, and food containing fat
  • Up to 37% of people can lose more than 5% of starting weight in just 12 weeks
  • Must have a BMI of 30 or more, or a BMI of 28 or above alongside health conditions to take Orlistat

alli

  • available over-the-counter
  • Oral 60mg tablet
  • Must be taken up to 3 times a day with water, and food containing fat
  • Contains the same active ingredient as orlistat (called orlistat), but is a different brand, price and lower dosage
  • Must be taken up to 3 times a day with water, and food containing fat
  • You must have a BMI of 28 or above to take alli
  • Up to 54.6% of people can lose at least 5% of their starting weight over 26 weeks

Mysimba

  • Prescription-only
  • Contains a combination of active ingredients naltrexone hydrochloride (8mg) and bupropion hydrochloride (90mg)
  • Works to reduce appetite and increase the amount of energy the body uses up
  • Taken according to a gradually increasing dosage schedule over 4 weeks
  • You must have a BMI of 30 or more or a BMI of 27 alongside weight-related health conditions to take Mysimba
  • Usually taken with food
  • Up to 50.8% of people can lose at least 5% of their body weight in 16 weeks

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crystal.png
Medically reviewed by:
Dr Crystal Wyllie Online Doctor

Crystal qualified in Medicine at Barts and the London School of Medicine and Dentistry in 2010. She then trained as a GP in London hospitals and practices. She has a particular interest in reproductive, sexual, and women’s health.

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Last reviewed: 28 Jan 2025



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