SINGAPORE - Prescription drugs Wegovy and Ozempic have been making headlines around the world for their off-label use as weight loss drugs.

The active ingredient in both brands is semaglutide, which can induce weight loss by curbing the appetite.

Ozempic was first approved by the United States Food and Drug Administration in 2017 to help those with Type 2 diabetes control their blood sugar levels, as part of a management plan.

Wegovy is the higher-dose version that was approved later on for those with obesity.

Both have been approved for use in Singapore.

Much has been written about the effects of Ozempic and Wegovy, but in Singapore, who should use it, what should users be aware of, and is the drug really what it is?

On The Straits Times’ podcast series Health Check, senior health correspondent Joyce Teo speaks to Dr Khoo Chin Meng, the head and senior consultant at the National University Hospital’s division of endocrinology, to find out more.

Here are some of the insights that Dr Khoo shared on the podcast, which will be released on April 5.

On why semaglutide or Wegovy is called a game-changing drug

It is more effective than the current available obesity drugs and generally well tolerated.

Some groups of people – such as those with a history of gallstones – cannot take it, but otherwise, the side effects associated with this medication are mainly gastrointestinal symptoms like nausea and vomiting. Some people may develop diarrhoea, while some may have constipation.

But the drug is costly. It is believed to cost about $300 per weekly dose. 

It is possible that some people with severe obesity will try semaglutide for weight loss before attempting bariatric surgery.

On why it’s not a miracle drug

Semaglutide mimics the action of a naturally occurring hormone in the body known as glucagon-like peptide 1 (GLP-1).

GLP-1 helps the body to produce more insulin when someone eats. This extra insulin will help to lower the blood sugar level after a meal.

GLP-1 also slows stomach emptying and makes the person feels full faster and longer, as well as acts on the brain to curb hunger.

It is important to understand that GLP-1 does not alter one’s eating behaviour, nor does it change the underlying factors of obesity.

Hence, there is a high risk of weight rebound, once a person stops using semaglutide.

On who can use the drugs in Singapore

In Singapore, Ozempic is approved for patients with Type 2 diabetes.

Wegovy is approved for patients who have a BMI (body-mass index) of 30 or more and those with a lower BMI of 27 or more, but who have co-existing weight-related medical problems such as high blood pressure or heart disease.

On the problem of the off-label use of Ozempic for weight loss

Using Ozempic for people without diabetes mellitus, for example to reduce body weight (let alone for those who wish to lose weight for vanity purposes) alone, might lead to supply shortage and thus deprive patients with Type 2 diabetes mellitus who need the drug.

On using semaglutide off-label 

Semaglutide is effective when used for weight loss in persons without disease, but the risks and benefits need to be established before the drug is prescribed. 

It is generally safe, however, the weight can rebound when the person stops using the drug and there is no long-term side effects data of this drug yet.