What are weight-loss jabs like Mounjaro and how do they work?

Hailed as a miracle weight-loss treatment, drugs such as Wegovy and Mounjaro have helped more than 500,000 people shed the extra pounds.

The medications, known as semaglutides, are available on the NHS or via private providers for adults with a high body mass index (BMI).

An online seller of these drugs, Simple Online Pharmacy, estimated that half a million people are currently either taking Mounjaro or Wegovy and expect to lose up to 20 per cent of their body weight in a matter of months.

The drugs can be used to control blood sugar levels as part of diabetes treatment, but they also reduce food cravings and, as a result, can cause rapid weight loss.

Here, The Independent breaks down how these drugs work and which jabs can be used for weight loss.

How do weight-loss jabs work?

Weight loss jabs, also known as GLP-1 receptor agonists, work by mimicking the natural hormone which regulates blood sugar, appetite and digestion.

They can be prescribed to lower blood sugar in people living with type 2 diabetes, but can also help people to lose weight.

Diabetes UK explains that the drugs increase the levels of a type of hormone called incretins, which help the body to produce more insulin when needed and lower blood sugar levels.

The drugs also reduce food cravings and slow down how quickly food is digested.

This can reduce the rate glucose is absorbed into the bloodstream. As a result, it makes those who take it feel fuller for longer, eat less and lose weight.

What are the side effects?

Although GLP-1 agonists have many benefits, like many drugs, there is a long list of possible side effects.

Nausea, diarrhoea, stomach cramps and vision problems are just some of the side effects listed in guidance by NICE.

However, they can also cause fatigue, drowsiness, headaches and hair loss.

What are the different types of GLP-1 agonists?

Ozempic

This is one brand name of semaglutide, which is injected and is prescribed to those with type 2 diabetes to manage blood glucose levels.

It is only supposed to be prescribed for diabetes management and not for weight loss, but is often prescribed “off-label” so people can buy it for that use.

Wegovy

This is another brand of semaglutide drug, but unlike Ozempic, Wegovy is available on the NHS to help with weight loss.

Mounjaro

This is the brand name of tirzepatide, another GLP-1 agonist and long-acting GIP (glucose-dependent insulinotropic polypeptide) receptor, which also plays a role in regulating blood sugar.

It is injected once a week and is used to treat type 2 diabetes and as a weight loss drug.

But you can only get tirzepatide on the NHS if it is prescribed by a specialist weight management service.