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Semaglutide guide: Weight loss, side effects and tips for use

How this active ingredient, found in Wegovy and Ozempic, works.

Semaglutide Injection: How It Works for Weight Loss | Juniper

Semaglutide and weight loss — you've probably heard these terms used in conjunction over the last few months. Semaglutide is a breakthrough drug treatment used for overweight or obesity management due to its effective results in producing significant weight loss results.

But how exactly does semaglutide for weight loss work? If you're just starting your weight loss journey or you've been at it for some time and can't seem to find something that works, you've come to the right place.

We're diving deep into everything you need to know about this new medication and how it can help with both weight loss and weight management.

What is semaglutide?

Semaglutide is a weight loss and chronic weight management medication that can be used in conjunction with lifestyle interventions.

This medication is the active ingredient in Ozempic, which is licensed to treat diabetes in the UK, and Wegovy, which is used to treat obesity. Semaglutide is a glucagon-like peptide 1 (GLP-1) which mimics the naturally occurring hormone that works to increase insulin secretion, reduce blood sugar levels and slows down gastric emptying [1].

How does semaglutide work?

Semaglutide mimics a natural hormone produced in the body called glucagon-like peptide 1, which is produced by the digestive system after eating food and acts on the brain to regulate the feeling of fullness after meals [2].

The GLP-1 hormone regulates insulin secretion in the body after eating meals, which helps your body better control blood sugar. Semaglutide can lower blood sugar levels and helps to suppress appetite by signalling to the brain that you've eaten a meal.

Semaglutide is administered via an injection with a pre-filled dosing pen once a week. The medication is injected under the skin into subcutaneous fat, with areas like the stomach, upper thigh and upper arm the best injection sites.

Semaglutide injection instructions

Semaglutide has been structurally modified to be a longer-lasting form of GLP-1, which delays your digestive process allowing you to feel fuller for longer, after a smaller-than-usual amount of food.

In practical terms, your brain's ‘hunger trigger' feels satisfied so you're less likely to consume snacks and larger meals, eating fewer calories overall. This decreased appetite and better insulin control of your blood sugar levels help with weight loss.

By targeting the receptors in the brain that control your appetite, semaglutide works to lower your body's ‘set point', which is the weight your body fights to maintain on a biological level.

Who can take semaglutide for weight loss?

Using semaglutide as a weight loss injection is suitable for those who:

  • Have a BMI of 30 or more, indicating obesity
  • Have a BMI of 27or higher and weight-related health complications such as high blood pressure, heart disease, cardiovascular disease or type 2 diabetes [3]

Semaglutide injections are not usually suitable for those who are/have:

  • Under 18 or over 75 years of age
  • Pregnant, breastfeeding, or trying for a baby
  • Type 1 diabetes
  • Thyroid cancer or family members with, or history of thyroid cancers
  • Multiple Endocrine Neoplasia type 2 (MEN2)
  • Liver disease
  • Kidney problems
  • Previous pancreatitis
  • Diabetic eye disease

Semaglutide for diabetics

GLP-1 reduces blood glucose levels by stimulating insulin secretion, which means it only works when blood glucose is high. It also lowers the secretion of glucagon (a hormone that increases blood glucose) when blood glucose is high.

Semaglutide in the form of Ozempic is used in the treatment for diabetes, while semaglutide in the form of Wegovy is used to treat obesity in the UK.

Is semaglutide safe?

Semaglutide is a safe and effective treatment when prescribed by a suitably qualified clinician. It was approved in the EU specifically by the European Medicines Agency and accepted for approval directly by the UK Medicines and Healthcare Regulatory Agency (MHRA) following Brexit.

This medication needs to be used in accordance with instructions given by your prescriber. As with all prescription medication, it can be harmful if it isn't used according to the instructions given by your prescriber or if it's taken by someone who it wasn't prescribed for. This can lead to serious side effects and risk of harm.

It's important to always follow the dosage and timetable of injections given by your prescriber and to keep the medication safely stored away.

How much weight can you lose on semaglutide injections?

Every weight loss journey is different. Some people will experience weight loss in their first week of taking semaglutide, while others begin to notice results a few weeks into treatment. Plus, we can't forget that losing weight with semaglutide also depends on the lifestyle changes you're making, like your nutrition, exercising regularly and even the dosage of medication you're taking.

But there have also been quite a few clinical trials into semaglutide and its effects on weight loss, so let's take a look at what the research says.

One study of 2,000 obese patients compared 2 groups: those who used semaglutide in combination with a diet and exercise program and those who made the same lifestyle changes but didn't use semaglutide [4].

After 68 weeks, participants in the semaglutide group lost 15% of their body weight and nearly a third lost 20%. On the other hand, those who didn't use semaglutide lost 2.4% of their body weight.

An additional clinical trial over a 2-year period compared patients who took 1mg of semaglutide in combination with lifestyle interventions with those who only implemented lifestyle interventions. The results showed patients taking semaglutide lost 4.9kg, whereas those who didn't use this medication only lost 0.5kg [5].

Looking at the Juniper Weight Reset Programme specifically, most people will lose at least 5% of their body weight in the first 20 weeks, and 1 in 4 will lose more than 10%. The effectiveness of our programme is down to combining medication with long-term lifestyle changes, rather than simply being a diet.

We help you better understand healthy eating, exercise and other habits that can help you lose weight and keep it off for good. You're supported every step of the way by healthcare professionals.

If you're not losing weight while taking semaglutide, be sure to reach out to your prescriber for support.

When do you start losing weight with semaglutide?

Everyone reacts to a new medication differently and the speed at which you can achieve weight loss will differ for everybody.

But, clinical trials evaluating weight loss outcomes as a result of taking semaglutide have shown that patients taking the 2.4mg dose achieved a weight loss of 6% by week 12 and by week 28, 12% of weight loss was achieved [6].

In another clinical trial over 12 weeks, patients taking the 1mg dose lost 4% of weight, and patients taking the 2.4 mg dose achieved 5% of weight loss. Weight loss at 28 weeks was 7% for those taking the 1mg dose and 9.6% for those taking the 2.4mg dose [6].

Essentially, within approximately 2-7 months, you can expect to achieve significant weight loss. The key is to make sure you're taking semaglutide in combination with making the necessary lifestyle changes like following a reduced-calorie diet and increasing your physical activity.

Semaglutide injection dosages

It's important to remember that semaglutide is a prescription medicine, meaning that you'll need to follow the dosage period given to you by your prescriber.

Over the duration of the treatment, your prescriber will increase your dose until you reach your therapeutic dose. Wegovy, which is a semaglutide medication, comes in a number of strengths: 0.25 mg, 0.5 mg, 1.0 mg, 1.7 mg, and 2.4 mg.

  • Starting dose: When using Wegovy injections, you'll start with the lowest dose of 0.25mg for a period of 4 weeks. This will give your body a chance to adjust to the medicine and reduce the risk of side effects. This dosage is intended for treatment initiation and isn't usually super effective, so don't worry if you don't start losing weight immediately.
  • Maintenance dose: Your prescriber at Juniper will usually titrate your dose upwards every 4 weeks as your body gets used to the treatment. During this time, you'll keep in touch with your prescriber at Juniper to determine when is best to increase your dosage. After 4 weeks of using a 0.25mg pen every week, you'll usually increase to a 0.5mg dose. Your dosage may then increase further over the coming weeks, up to 2.4mg.

How long can I use semaglutide?

Semaglutide medication Wegovy has been developed for long-term use but the length of time you need to take it will differ from person to person. It is important to discuss the long-term use of Wegovy with a healthcare professional to determine if it is the right option for you and to discuss potential risks and benefits.

It's also important to find support for making additional lifestyle changes, such as consuming a reduced-calorie diet and increased physical activity. You can work with your prescriber to find a duration that works for you.

How do I stop taking semaglutide?

After you stop taking Wegovy, it can take your body around 5-7 weeks to fully clear the medication from your system [7]. This means that you may still experience some of the effects of Wegovy during this period.

You'll need to maintain the healthy nutritional and lifestyle habits that you developed during the Juniper Weight Reset Programme in order to sustain your achieved weight loss.

What are the side effects of semaglutide?

As with most prescription medications, semaglutide can cause some side effects or allergic reactions. Mild and temporary symptoms are expected in 1 in 10 patients.

Common side effects of semaglutide, for the minority of patients that experience them, include:

  • Loss of appetite
  • Mild nausea (feeling sick)
  • Vomiting (being sick)
  • Dizziness
  • Fatigue
  • Headache
  • Abdominal pain or stomach cramps
  • Acid reflux/heartburn
  • Diarrhoea, constipation or upset stomach
  • Burping and flatulence

Many of these side effects are caused by knock-on impacts rather than the medication itself. For example, vomiting can lead to dehydration, which presents itself as a headache and fatigue. It's important to make sure you stay hydrated and eat a balanced diet with regular meals throughout the day whilst taking Ozempic.

If you do experience any of these side effects whilst on the Juniper Weight Reset Programme, our team is here to help you. Contact us at hello@myjuniper.co.uk and we'll advise you on how to mitigate your symptoms or arrange a consultation with your clinician to review your treatment plan.

In very rare cases, should your side effects be acute, or if you have symptoms of a severe allergic reaction (such as swelling of your face, lips or throat, problems breathing or swallowing or a rapid heartbeat), we recommend seeking immediate medical assistance through your GP or nearest A&E emergency room service.

Is Wegovy the same as Ozempic?

Wegovy is an exciting development in the field of weight management. Similar to Ozempic, its active ingredient is semaglutide but the medications are licensed for different uses as well as the dosages they are given in.

Ozempic has been used for several years within the NHS to treat type 2 diabetes, while Wegovy is medically licensed for weight management. When it comes to dosages, Ozempic is provided in dosages up to 1mg weekly which effectively manages blood sugar in diabetic patients. By contrast, Wegovy will go up to 2.4mg weekly for weight loss.

Is Wegovy the same as Saxenda?

Whilst they have a similar effect on our bodies, Wegovy and Saxenda are trade names for 2 different active ingredients. Wegovy contains semaglutide, while Saxenda contains liraglutide.

Both active ingredients are GLP-1s, which act to slow your stomach from emptying and help decrease your appetite.

There are, however, some key differences between the medications:

  • Semaglutide has a longer duration of action and has been proven in clinical trials to be more effective for weight management [8]
  • Wegovy is a weekly injection, versus Saxenda which is a daily injection
  • Clinical trial participants felt side effects for a longer period of time with Saxenda than with Wegovy

Is semaglutide available on the NHS for weight loss?

Semaglutide is available on the NHS, but it's only available for patients with type 2 diabetes. The National Institute for Health and Care Excellence (NICE) recommends taking semaglutide for clinically obese patients or those who are significantly overweight with a weight-related condition

The eligibility criteria for semaglutide in the UK include:

  • You have a body mass index of 30 or more (clinical obesity)
  • You have a body mass index of 27 or more (significantly overweight) and you also have a weight-related condition that is caused or made worse due to excess body weight.

In addition, NICE says semaglutide can only be prescribed as part of a specialised weight management service with multidisciplinary input and for a maximum of 2 years [9].

You can access semaglutide as a weight loss and weight management treatment through Juniper’s Weight Reset Programme — if you're aged between 18 and 75 and meet the baseline characteristics required for treatment.

Plus, we know it's important to look beyond just weight loss medication for reducing body weight and achieving weight loss. That's why Juniper's weight loss and weight management programme takes a holistic approach backed by health coaching, lifestyle changes and diet advice.

Through weight loss medication, we aim to give your body a biological reset that targets areas of the brain that regulates appetite and lowers your body's set point, in turn, helping you kick your weight loss goals.

Our clinical team of healthcare professionals, health coaches and dietitians are also involved in the weight loss journey with you, giving you all the tools and support needed to not only lose weight but keep it off, too. Our health coaches guide you with helpful and actionable advice to help you make the necessary lifestyle changes, like sticking to a reduced-calorie diet and increasing your physical activity levels.

We know losing weight can be really challenging, especially on your own, which is why we connect you with others on the journey to keep you motivated and celebrate your weight loss success.

Weight loss and weight management can be difficult and breakthrough medications like semaglutide can be helpful in tackling these. If you'd like support on your weight loss journey, we can help.

Foods to avoid while on semaglutide

Heavy alcohol use should be avoided while taking GLP-1 medications. While the drug isn't known to interact with alcohol, heavy consumption can lower blood sugar levels and in the long term, it can also increase the chance of pancreatitis, a rare side effect of semaglutide.

If you're taking semaglutide, aim to include fruits, vegetables, whole grains, healthy fats, and protein-rich foods in your diet, while trying to steer clear of refined grains as well as large amounts of added sugar and fried foods.

Is semaglutide worth the risk?

We'll answer in terms of using semaglutide or Wegovy for weight loss. The greatest benefit of taking this medication is that patients can lose a meaningful amount of weight, which has many associated health benefits.

Semaglutide isn't suitable for people with certain health issues, but for those who are eligible, the risk is typically low and the health benefits of losing weight tend to outweigh the potential side effects of taking the medication.


Like with all medications, for certain people, semaglutide should be used with caution. Some precautions include:

  • Diabetic retinopathy
  • Pancreatitis
  • Gallbladder disease
  • Kidney problems
  • Stomach/intestinal disorders (such as gastroparesis and serious digestion problems)

There is limited data on the use of this medication in pregnant women. Women of childbearing potential are recommended to use contraception when treated with semaglutide, so the medication shouldn't be used during pregnancy. If a patient wishes to become pregnant (or pregnancy occurs), semaglutide should be discontinued at least 2 months before a planned pregnancy.

The medication can be excreted in breast milk and as such, shouldn't be used during breastfeeding, as there is no data on safety for breastfed infants.