Explainer: Semaglutide, Ozempic and Wegovy and weight loss

Celebrities are raving about it, people wanting to lose weight are craving it, and if you’re a diabetic right now you probably want drug prescribers to be saving it.

Semaglutide – sold under the labels Ozempic and Wegovy – is the latest tool in a long line of weapons used in the proverbial war against the waistline.

From diets to supplements and a swathe of specialised pharmaceuticals, the world has been looking for an easy and effective way to trim the tummy and in semaglutide, some think they finally have an answer.

But it’s not without risks, and the medical and healthcare communities have concerns about its use.

There’s also a long-standing global shortage.

So what does the public need to know about this medication and how are people able to access it?

What is semaglutide?

GLP-1 is a hormone naturally produced in the gut, which stimulates insulin and urine production, slows the emptying of the stomach and, as recently discovered, reduces appetite.

Semaglutide is the compound in Ozempic which is a receptor agonist – it mimics the effects of GLP-1 by binding to GLP-1 brain receptors. This signals the body to make more insulin and lower blood sugar levels. Semaglutide is one type of GLP-1 RA.

What is Ozempic?

Ozempic is semaglutide, in the same way that Panadol is paracetamol – it’s simply the brand name that manufacturer Novo Nordisk slaps on the packet.

It’s an important medication for diabetics to manage their blood glucose levels, and like other commonly prescribed diabetes medication such as Metformin, is taken as a pen-delivered injection. Ozempic is dispensed in doses of 0.25mg or 0.5mg once per week.

While weight loss is a known side effect of taking Ozempic, manufacturer Novo Nordisk does not indicate it for use as a weight loss drug, though, GPs around the world have been prescribing it ‘off label’ for this purpose.

What’s Metformin?

Metformin is the most prescribed diabetes medication, belonging to a class of drugs called biguanides. It’s commonly sold under the Diabex, Diaformin, Metex and Glucophage brands and helps to reduce glucose production in the liver and absorption in the gut. It’s a vital medication in controlling blood sugar in diabetics who can’t rely entirely on a good diet and exercise.

In Australia, the Therapeutic Goods Administration (the equivalent of the FDA in the United States), indicates Ozempic as a drug of choice where metformin isn’t tolerated or contraindicated – basically, when a person can’t have metformin, Ozempic can be considered.

Is Wegovy the same as Ozempic?

Yes. And no.

Wegovy is a once-a-week injection but of a higher semaglutide dosage – 2.4mg compared to 0.25 and 0.5mg for Ozempic. Novo Nordisk indicates its use as a weight loss drug for people whose BMI is over 30 for adults, or in the upper 5% of age for children.

The TGA indicates Wegovy for use alongside a low-energy diet and exercise for chronic weight management in adults with a BMI of 30 or more, or 27-30 when they may have other health issues.

Ozempic and Wegovy are medicines, and there’s currently a global shortage

Beyond the hype, it’s important to bear in mind that semaglutide is a regulated medicine in Australia. That means you can’t just roll into a chemist and buy it off the shelf. It’s also a vital medicine for people with diabetes, especially those who can’t use metformin.

In September, the TGA confirmed through Novo Nordisk that semaglutide supplies in Australia would be limited until the end of 2024. That’s bad news for people who rely on the drug for managing blood sugar. As a result, the TGA advised doctors to stop prescribing Ozempic to new patients unless “there are no suitable alternatives, or […] a compelling clinical reason to do so”.

Side-effects, fakes and overdosing.

Amid the widespread coverage of Ozempic in the press, experts have consistently noted the importance of discussing options for managing diabetes or weight with qualified healthcare professionals. 

Semaglutide won’t be suitable for everyone, and like any drug, there are known side effects, which include nausea, abdominal pain, diarrhoea and vomiting. These are adverse effects often found, according to the TGA, in most other GLP-1 RA drugs.

As the hype about these drugs has built, so too has the risk of counterfeit drugs entering the market, with illegal importations uncovered in May 2023.

Misuse of the drug has also been associated with increased emergency calls and a surge in social media and influencer promotion. 3 in 4 calls to the New South Wales Poisons Information Centre between September 2019 and August 2022 were related to incorrect self-administered dosages, compared to 1 in 6 due to adverse reactions.

When it comes to weight loss, Ozempic and Wegovy require sustained use for clinical benefit

The indications for the use of semaglutide drugs clash with the portrayal of their benefits in the media and the way they’re described as a miracle therapy in celebrity circles.

That’s a point driven home by Associate Professor Priya Sumithran, an endocrinologist and head of the Obesity and Metabolic Medicine Group at Monash University.

Semaglutide is prescribed alongside recommendations for maintaining a healthy diet and regular exercise in Australia and the US. It requires continuous use to maintain weight loss.

“The fact that there is this new generation of medications that are a lot more effective than things that we’ve had before, that’s probably the reason why they have been so well publicised,” says Sumithran.

“[But] the purpose of using medications, both to treat diabetes and also to help people reduce their weight is to improve their health – we know that controlling blood sugar in people with diabetes is good for their longer-term health.

“In people without diabetes, all medications that are approved for weight management have to show in clinical trials that they also improve health and not just reduce weight.”