Best weight loss injections

Weight loss injections have become increasingly popular as effective, medically supervised treatments for obesity management. In this guide, we compare four leading weight loss injections available in the UK: Wegovy, Mounjaro, Ozempic, and Saxenda.

Learn about their active ingredients, mechanisms of action, weight loss potential, dosing schedules, common side effects, and pricing to help you choose the best option for your needs.

Comparing the best weight loss injections

Injection

Wegovy

Mounjaro

Saxenda

Ozempic

Active Ingredient

Semaglutide

Tirzepatide

Liraglutide

Semaglutide

Manufacturer

Novo Nordisk

Eli Lilly

Novo Nordisk

Average Weight Loss

21%¹

20.2%²

7.7%⁴

7%⁶
(off-label use)

Indications

Weight loss for adults with BMI ≥30 or ≥27 with comorbidities

Weight loss and type 2 diabetes management for adults with BMI ≥30 or ≥27 with comorbidities

Weight loss for adults with BMI ≥30 or ≥27 with comorbidities

Type 2 diabetes management (off-label for weight loss)

Mechanism of Action

GLP-1 receptor agonist; reduces cravings, delays gastric emptying, stabilises blood sugar, quiets food noise, promotes metabolic efficiency

Dual GLP-1 and GIP receptor agonist; reduces appetite, delays gastric emptying, regulates blood sugar levels

GLP-1 receptor agonist; regulates appetite

Same as Wegovy; lower doses targeted at glycaemic control

Dosing Schedule

Weekly injections; 5 strengths with doses starting at 0.25mg up to 2.4mg

Weekly injections; 6 strengths with doses starting at 2.5mg up to 15mg

Daily injections; 5 strengths with doses starting at 0.6mg up to 3mg

Weekly injections; 4 strengths with doses starting at 0.25mg up to 1mg

Common Side Effects

Nausea, diarrhoea, vomiting, constipation, stomach pain, headache, tiredness, upset stomach, dizziness, feeling bloated, belching, gas, stomach flu, heartburn, and runny nose or sore throat3

Nausea, diarrhoea, decreased appetite, vomiting, constipation, indigestion, and stomach pain2

Nausea, diarrhoea, vomiting, constipation, injection site reaction, low blood sugar, stomach pain, headache, tiredness, upset stomach, dizziness, change in enzyme levels in your blood5

Nausea, diarrhoea, vomiting, constipation, and stomach pain⁷

Which weight loss injection is best for you?

Choosing the best weight loss injection depends on your medical history, lifestyle preferences, and eligibility.

It’s important to always consult a healthcare provider before starting any medication. All of these medications are prescription-only, so you’ll have the opportunity to ask questions and seek more personalised information before you begin treatment.

If you prefer weekly dosing and significant weight loss potential, consider Wegovy or Mounjaro.

For daily dosing or if Wegovy/Mounjaro are unsuitable, Saxenda may be a good alternative.

Ozempic is a cost-effective option for off-label weight loss but is primarily licensed for diabetes and is less effective for weight loss than Mounjaro or Wegovy.

What are the benefits?

Weight loss medication, when prescribed and monitored by a healthcare professional, can be a powerful tool to support people who are struggling with obesity or excess weight. Here are some of the key benefits:

Effective weight reduction

Many people experience significant and sustained weight loss when using approved weight loss injections.⁸

Juniper patients are 4.5x more likely to lose significant weight than people on medication alone.⁹

Appetite control

These medications work by mimicking hormones that regulate hunger, helping to reduce food noise, cravings, and promote a feeling of fullness.⁸

Improved metabolic health

Weight loss medications can improve insulin sensitivity and lower blood sugar levels, which is especially beneficial for those with type 2 diabetes or pre-diabetes.⁸

Cardiovascular benefits

Some weight loss medications have been shown to reduce the risk of heart-related conditions by improving blood pressure, cholesterol levels and overall cardiovascular health.¹⁰

Joint and mobility improvements

As weight decreases, there is less pressure on joints, which can lead to less pain and greater ease of movement.¹¹

What are the risks?

All medications carry the risk of side effects, and we’ve outlined the most common ones in the table above. Other risks of weight loss injections include:

Weight regain

Weight loss injections are highly effective tools to help you lose weight, but if it’s not paired with behaviour change, the risk of regaining the weight is higher.¹²

Gallbladder and pancreatic issues

Rapid weight loss can increase the risk of gallstones and pancreatitis, sometimes requiring surgery.¹³

Body composition shifts

Weight loss injections can increase muscle loss compared to when losing weight through diet and exercise alone.¹⁴ That’s why it’s important to pair any medical treatment with strength training and proper nutrition - particularly focusing on protein.

Financial burden

Relatively high costs and lack of insurance coverage can create barriers to ongoing use, which could lead to abrupt discontinuation of the medication.

Psychological dependence

While rare, the rapid results and injectable administration may foster misuse or addiction-like reliance.¹⁵

Are weight loss injections available on the NHS?

The NHS has deemed tirzepatide, semaglutide and liraglutide safe and effective for weight management.

Wegovy and Saxenda must be prescribed by a specialist weight management service, along with eating a balanced, reduced-calorie diet and regular exercise.

To be prescribed Wegovy (semaglutide) you must have health problems due to your weight and a BMI of:
‍

35 or more, or 32.5 or more if you’re of Asian, Chinese, Middle Eastern, Black African or African-Caribbean origin
30 - 34.9, or 27.5 - 32.4 if you’re of Asian, Chinese, Middle Eastern, Black African or African-Caribbean origin, and you meet other criteria to be treated by a specialist weight management service

To be prescribed Saxenda (liraglutide), all of the following must apply:
‍

you have a BMI of 35 or more, or you have a BMI of 32.5 or more and you’re of Asian, Chinese, Middle Eastern, Black African or African-Caribbean origin
you have non-diabetic hyperglycaemia
you’re at high risk of heart problems because you have high blood pressure or high cholesterol

As of June 2025, Mounjaro (tirzepatide) can be prescribed by GPs in England but availability is restricted, with the initial rollout planned to reach 220,000 people over 3 years. As such, officials are advising individuals to refrain from contacting their GPs about the weight loss medication unless they meet the following criteria:
‍

Year 1: BMI ≥ 40 (or ≥ 37.5 for some ethnic groups) and 4 or more weight-related comorbidities (e.g. type 2 diabetes, high blood pressure, sleep apnoea)
Year 2: BMI 35 to 39.9 and still require 4 or more co-morbidities
Year 3: BMI ≥ 40 and 3 or more co-morbidities

A full rollout is planned over 8 further years, eventually covering patients with BMI ≥ 35 and at least one comorbidity. prescribed Saxenda (liraglutide), all of the following must apply:

What will doctors consider?

When evaluating your suitability for weight loss injections doctors will evaluate several clinical and contextual factors to ensure it’s safe for you. These are some of the most common ones, but this is not an exhaustive list.

BMI and weight-related conditions

Typically you will need to have a BMI of at least 30 or a BMI of at least 27 with comorbidities like hypertension, type 2 diabetes or sleep apnoea to be approved for weight loss injections.

Medical history

There are medical conditions (like pancreatitis or severe renal impairment) that may make weight loss injections unsuitable for you. These medications are also contraindicated if you are pregnant or breastfeeding.

Mental health history

Having a history of eating disorders or major depression may mean that weight loss medication is not recommended for you.

Which weight loss injection is best for you?

Weight loss injections offer several advantages compared to traditional methods like diet or exercise alone:

Medical supervision

These treatments are prescribed and you are monitored by healthcare professionals. If you experience any side effects or things aren’t progressing as they should, you’ll be able to get help straight away.

Higher effectiveness

Clinical studies consistently demonstrate greater weight loss compared to lifestyle changes alone.¹⁶

Medical supervision

Weekly or daily injections can be easier to integrate into daily routines than restrictive diets or intensive exercise regimens.

However, other methods like bariatric surgery or lifestyle interventions may be more suitable depending on individual needs and medical history. Combining weight loss medication with healthy eating habits and regular physical activity often provides the best results.

Costs

Juniper offers both Wegovy and Mounjaro as part of our Weight Reset Programme. Wegovy ranges in price from £189 to £299 per month depending on dosage. Mounjaro ranges in price from £189 to £249 per month depending on dosage. Given their lower effectiveness for weight loss, we do not offer Saxenda or Ozempic. However, on average we found Saxenda (6mg/ml) priced from £289 per month and Ozempic priced from £149 per month.

Weight loss injections such as Mounjaro, Wegovy, Ozempic, and Saxenda are innovative solutions for managing obesity when combined with a holistic approach to health.

Each medication offers unique benefits tailored to different needs, making it essential to consult a healthcare provider before starting any treatment. With patience, consistency, and the right support system, lasting weight loss is achievable.

FAQs

Medically reviewed by

Kevin Joshua, BSc (Hons)

Superintendent Pharmacist and Clinical Operations Lead | Juniper

Kevin Joshua

BSc (Hons) Pharmacy, MRSPH (Member of the Royal Society for Public Health)

Kevin Joshua is Juniper’s Clinical Lead and Superintendent Pharmacist. In his role, he designs and delivers specialised support services to help patients access care beyond what the NHS can provide, with a particular focus on weight management and a keen interest in menopause support.

Passionate about achieving the best health and wellbeing outcomes for patients, Kevin is dedicated to delivering a service where every patient feels valued and safe.

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2. https://investor.lilly.com/news-releases/news-release-details/lillys-zepboundr-tirzepatide-superior-wegovyr-semaglutide-head
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4. https://www.novomedlink.com/obesity/products/treatments/saxenda/efficacy-safety/significant-weight-loss.html
5. https://www.saxenda.com/about-saxenda/side-effects.html
6. https://pubmed.ncbi.nlm.nih.gov/33667417/
7. https://www.ozempic.com/how-to-take/side-effects.html
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13. https://www.bhf.org.uk/informationsupport/heart-matters-magazine/news/behind-the-headlines/weight-loss-injections
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16. https://www.nejm.org/doi/10.1056/NEJMoa2032183
17. https://www.nature.com/articles/s41591-023-02597-w
18. https://www.nejm.org/doi/full/10.1056/NEJMoa2032183
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