What are weight loss injections and are they safe?

What are weight loss injections?

You may have seen celebrities such as Gemma Collins take to social media to promote weight loss injections and praise the "skinny jab". It may be tempting to think of these injections as a quick and easy fix to your weight problem, but in truth, they can only work if you make the necessary lifestyle changes too.

If you're considering weight loss injections, it's important to understand that this treatment is designed to address weight-related health issues. According to The National Institute for Health and Care Excellence (NICE)¹, this medicine is only right for you if all of the following applies:

• You have a BMI (body mass index) of 35 or more - classified as obese.

• You have non-diabetic hyperglycaemia - blood sugar that is above normal but below those needed to diagnose diabetes.

• You are at high risk of other weight-related conditions such as strokes and heart attacks, because of other factors such as high blood pressure and high cholesterol.

When it comes to weight loss, one size certainly doesn't fit all. If you don't meet these criteria but are unhappy with your size, speak to your GP about losing weight safely. This will always involve healthy eating and regular exercise, but there are various support services that can make your weight loss journey that little bit easier.

How do weight loss injections work?

Saxenda

Saxenda - also known as liraglutide - is a weight loss medicine that you inject once a day to make you feel more full and less hungry.

This drug emulates a natural hormone found in the body that regulates your appetite, which can help you to consume fewer calories and lose weight. As with any weight loss treatment, this injection will only work if you also stick to a healthy diet and exercise plan. Studies show that Saxenda can lead to 4-6 kg of weight loss².

Wegovy

In 2023, Wegovy - also called semaglutide - joined Saxenda and became the second injectable drug available on the NHS in England. In March 2023, NICE approved this popular US drug for the UK, concluding that it is a safe and effective weight loss treatment.

Like Saxenda, Wegovy makes you feel fuller for longer by mimicking an intestinal hormone. But while Saxenda is injected daily, Wegovy is injected weekly. There's also evidence that Wegovy may be more effective for weight loss than Saxenda⁴. According to NICE, the new drug may help people reduce their weight by more than 10%, so long as they follow their diet and exercise plans⁵.

Aqualyx

There are other weight loss injections available in private practices, one of which, Aqualyx is a fat-dissolving injection that's widely available in the UK and is generally considered safe⁶, so long as it's administered by a trained healthcare professional.

A non-surgical alternative to liposuction, Aqualyx works by attaching to deposits of fat and gradually breaking them down until they are naturally flushed out of your body. As such, this injection can be used in a more targeted way than Saxenda and Wegovy, for example to decrease mass in your upper arms, stomach, or inner thighs.

Mounjaro

November 2023 saw another weight-loss injection receive approval for use in the UK. Mounjaro, also known as tirzeppatide, is now authorised for adults who have diabetes, who are obese, or who are overweight with related health problems such as prediabetes and heart problems⁷.

Like other weight loss drugs, the active ingredient in Mounjari helps you feel fuller for longer by emulating the hormone responsible for appetite. What makes this injection different is that it also alerts the pancreas to stop releasing insulin after eating and signals the liver to release less glucose (blood sugar). This helps regulate blood sugar, making it an effective management tool for diabetes management.

How much do weight loss injections cost?

These injections come with a hefty price tag. Although it varies between health providers, Saxenda pens cost roughly between £45 and £75. The costs quickly ramp up, given that the NHS recommends three months of treatment, and people tend to get through five injectable pens each month. Aqualyx is usually administered by a professional in two to four sessions, each visit costing upwards of £300. The price of Wegovy ranges from around £200 to £300, but is available on the NHS under certain criteria. As of November 2023, the price of Mounjari is yet to be confirmed.

If you meet the criteria, Saxenda and Wegovy are now available through the NHS, and Mounjari will be soon. This is part of the NHS's bid to reduce healthcare costs attributed to weight-related health issues - projected to reach £9.7bn by 2050⁸⁷. However, wait times are likely to be long, and your doctor may only recommend weight loss injections when other weight loss treatments have proven ineffective.

You can also get it on private prescription in high-street pharmacists like Boots and through pharmacies in Patient Access if you meet the criteria.

Are weight loss injections safe?

Saxenda is considered to be safe and is well-tolerated by most people⁹⁸. Several clinical trials have also shown Aqualyx to be safe when administered correctly by a trained professional¹⁰⁹, although there is less research for this drug than Saxenda.

However, like all medicines, there are possible side effects to consider.

Possible side-effects of Saxenda

The most commons side effects¹¹⁰ include:

• Nausea/ vomiting.

• Diarrhoea/ constipation.

• Low blood sugar (hypoglycaemia).

• Headache.

• Tiredness (fatigue).

There are a few documented cases of long-term and severe adverse reactions. These include:

• Inflammation of the pancreas (pancreatitis).

• Gallbladder problems.

• Liver or kidney problems.

• Increased heart rate.

• Depression/ suicidal thoughts.

• Serious allergic reactions - symptoms may include swelling of your face, lips, tongue, or throat and a very quick heartbeat, breathing or swallowing difficulties, or a severe rash. At worst, anaphylaxis.

It is not known if this medication can cause thyroid tumours or thyroid cancer, but medicines that work like Saxenda have caused these conditions in studies with rats. For this reason, you shouldn’t take this injection if you or someone in your family has ever had medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2)¹⁰.

There are several other health conditions and medications that can make the Saxenda weight loss injection unsafe for you to take. Your healthcare expert will be able to advise if this is the case.

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Possible side-effects of Wegovy

The most commons side effects¹¹ include:

• Nausea/ vomiting.

• Diarrhoea/ constipation.

• Stomach pain.

• Headache.

• Tiredness (fatigue).

• Bloating, belching and wind.

• Stomach flu.

• Heartburn.

There are a few documented cases of long-term and severe adverse reactions. These include:

• Inflammation of the pancreas (pancreatitis).

• Gallbladder problems.

• Kidney problems.

• Increased heart rate.

• Depression/ suicidal thoughts.

• Serious allergic reactions - symptoms may include swelling of your face, lips, tongue, or throat and a very quick heartbeat, breathing or swallowing difficulties, or a severe rash. At worst, anaphylaxis.

• For people with type 2 diabetes - there are additional risks of low blood sugar and changes in vision.

As with Saxenda, it is not known if Wegovy causes thyroid tumours or thyroid cancer, and so avoid this drug if you or someone in your family has ever had MTC or MEN 2. As other health conditions and medications may make Wegovy unsafe for you, always follow your healthcare expert’s advice.

Possible side-effects of Aqualyx

The most common side effects usually clear within a few days. These include¹²:

• Redness of the skin.

• Bruising.

• Swelling.

• Skin lumps - usually associated with incorrect application.

The only serious adverse effects that have been reported are scarring and skin necrosis - where skin tissue dies resulting in a permanent visible dark mark¹³. These cases are very rare, but it should be noted that experts believe we need more studies of Aqualyx to fully understand exactly how safe and effective this drug is.

Three key safety tips

1. Don't neglect diet and exercise

Remember, weight loss injections aren't miracle drugs - only by reducing your calorie intake, following a nutritious diet, and increasing your physical activity will you achieve a healthy body weight. It's these major lifestyle changes that will help you to keep the weight off and reduce your risk of weight-related health conditions.

2. Choose a trusted healthcare provider

In the UK, there have been reports of unregulated imports of weight loss injections and non-medically qualified practitioners. This weight management technique is only safe if carried out by a qualified and trained professional. The new government pilot to make Wegovy available outside hospitals, although a less closely regulated approach, will look at using other healthcare professionals - like GPs - and doesn't condone administration by non-medical practitioners.

What to look for in a provider:

• Medically qualified clinicians - for example, doctors or dentists have done extensive studies in anatomy and physiology.

• Additional specialist training in aesthetics.

• Reputable products - when asked where they source this medication, your provider should be able to name a trustworthy UK pharmacy.

• Suitable insurance - your provider should have insurance specific to carrying out aesthetic procedures.

3. Disclose your medical history

A trustworthy provider should always do a thorough check of your medical record and ask questions to determine if weight loss injections are a suitable and safe treatment path for you. You should disclose any current or previous medical conditions and medications that you have taken.

Further reading

1. NICE: New treatment recommendation.

2. A. Talathi and P. Talathi: Fat busters: lipolysis for face and neck.

3. GOV.UK: New drugs pilot to tackly obesity and cut NHS waiting lists.

4. NICE: Semaglutide for managing overweight and obesity.

5. NICE: NICE recommended weight-loss drug to be made available in specialist NHS services.

6. Mlosek: Lipoma removal using a high-frequency ultrasound-guided injection of a Class III CE-marked device-Empirical findings.

7. GOV.UK: MHRA authorises diabetes drug Mounjaro (tirzepatide) for weight management and weight loss.

8. Public Health England: Health matters: obesity and the food environment.

9. Ponzani: Long-term effectiveness and safety of liraglutide in clinical practice.

10. Hoffmann, Injection lipolysis.

11. Saxenda: Indication and important safety information.

12. Wegovy: Side effects.

13. Aqualyx: Treatment information.

14. Toro and Rauso: Skin necrosis following adipocitolitic solution injections.