How Semaglutide (Ozempic, Wegovy) Helps Weight Loss

Semaglutide, widely known by its brand name Ozempic, and recently Wegovy, has been making headline news recently, with celebrities such as Elon Musk publicly touting the drug’s effectiveness when it comes to losing weight. But how has a medicine used to treat diabetes become synonymous with getting a ‘killer bod’? And more importantly, does it actually help weight loss?

What is Semaglutide?

Semaglutide is the active ingredient in Ozempic and Wegovy. Semaglutide was developed by Novo Nordisk in the early 2010s as a longer-acting alternative to a similar drug called liraglutide. Semaglutide was quickly considered an attractive anti-diabetic option. Not only was the once-weekly injection convenient to administer, semaglutide outperformed other more established anti-diabetic drugs in clinical trials, delivering more sustained reductions in blood sugar (glucose) levels and weight.

In 2018, Ozempic was granted a UK license so that it could be used to treat adults with insufficiently controlled type 2 diabetes mellitus. Ozempic can be prescribed in conjunction with other anti-diabetic medication, or in certain cases, just by itself to treat diabetes. Recently in 2021, Wegovy was approved by the UK regulatory agency for the purpose of weight loss in obese adults with a BMI ≥30 kg/m2.

How does Semaglutide work?

Our bodies naturally produce a hormone called glucagon-like peptide-1 (GLP-1). GLP-1 has a few notable physiological properties that make it a useful target when treating diabetes, mainly its ability to increase insulin levels, slow down the body’s production of glucose, as well as reduce a person’s appetite.  

Semaglutide is an agonist of the GLP-1 receptor, meaning it mimics the action of the natural GLP-1 hormone.

How does Semaglutide cause weight loss?

Semaglutide acts on GLP-1 receptors in the brain to make a person feel more sated and full. It also acts on the gut to slow down the passage of food, therefore causing a collective reduction in appetite. Trials of semaglutide showed that the drug not only drove people to consume less calories, it also helped improve a person’s control over their eating, reduce food cravings and decrease their preference for higher fat foods. When used as an adjunct to diet and exercise, it is easy to see how this drug can be effective at helping people lose weight.

What are some of the side effects from Semaglutide?

Common side effects can include nausea, constipation and diarrhoea, while less common side effects include altered taste and acute pancreatitis, which is inflammation of the pancreas. 

It is important that read the Patient Information Leaflet (PIL) included with the medication, and that you take individual advice from your healthcare team before starting Ozempic treatment and report any side effects if you experience any.

Can doctors prescribe Ozempic or Wegovy specifically for weight loss?

The short answer is yes. If Ozempic is prescribed only for weight loss and not to treat diabetes, this is considered an off-label (or off-license) use of the drug. It is important to note that prescribing Ozempic off-label is not illegal. Off-label prescribing of drugs is common practice in healthcare to treat conditions where a licensed alternative is not available – you can read more about it here in this leaflet by Oxford University Hospitals.

The use of Ozempic in helping patients lose weight attained so much mainstream attention that the company developed another semaglutide product, branded as Wegovy, specifically for the purpose of weight loss. Wegovy received US FDA and UK MHRA approval in 2021 and was approved by the EU in 2022.

It is important to note that Wegovy is licensed in the UK for weight management if a person is obese (BMI ≥30 kg/m2), or is overweight (BMI ≥27 kg/m2 to <30 kg/m2) with at least one weight-related condition. If you do not fall in either category, the prescribing for Wegovy will still be considered off-label.

What should I know before I decide to pursue Ozempic or Wegovy for weight loss?

Semaglutide, whether the Ozempic or Wegovy brand, is a prescription-only medication (POM) in the UK. This means it can only be prescribed by an accredited healthcare professional competent in this field of treatment.

Therefore, you must be prepared to attend consultations with the prescriber and have your medical history and vitals (like body weight, blood pressure, heart rate etc.) taken to ensure you are suitable for semaglutide. Semaglutide should not be used in certain groups of people, for example in pregnant or breastfeeding women or people with moderate to severe heart failure. Your healthcare professional will be able to advise you more on whether you are suitable.

It is also important to remember – the drug does not work miracles. You still need to put in the hard work of having a healthy diet and exercising to get the weight loss effect you desire.

The drug is also not without its side effects. Although most of the gut-related effects like nausea, constipation and diarrhoea are self-limiting and generally subside over time, semaglutide has been linked to rare cases of acute pancreatitis.

Acute pancreatitis is a condition where the pancreas becomes inflamed (swollen) over a short period of time. Look out for common symptoms of acute pancreatitis, which include a sudden severe pain in the centre of your tummy, nausea and vomiting, and a high temperature of 38C or more (fever). Read more about it here. In instances where you suspect acute pancreatitis, speak to your GP immediately or ring NHS 111.