Today brings much excitement in the Canadian obesity treatment landscape: semaglutide 2.4mg (trade name Wegovy) has now been approved for weight management in Canada.  It was approved in USA in June 2021, and has been approved in the United Kingdom as well.


As blogged previously here , here and here, in the STEP clinical trial program, semaglutide 2.4mg taken once weekly demonstrated 16-18% weight loss together with lifestyle intervention in people without diabetes, and about 10% weight loss in people with type 2 diabetes.

Many important health benefits were seen in the STEP clinical trials, including improvements in blood pressure, blood sugars, inflammation, quality of life, and physical functioning.



Semaglutide 2.4mg has recently been studied in the STEP8 trial in comparison to its older cousin, liraglutide 3mg (trade name Saxenda), which is an existing treatment for weight management in over 60 countries (including Canada).  Semaglutide treated patients demonstrated an impressive 15.8% weight loss at 68 weeks, vs 6.4% weight loss with liraglutide 3mg, vs 1.9% with placebo (with all participants receiving lifestyle counseling).


Data now exists out to 2 years with semaglutide 2.4mg in the STEP5 trial, showing sustained weight loss.  This study also demonstrated that semaglutide 2.4mg doesn’t just work by reducing appetite, but also by controlling cravings. My patients will often tell me that they feel challenged by difficult to resist cravings, so it’s great to know that semaglutide may be able to help with this.  (note that the weight management medication naltrexone/bupropion (trade name Contrave) has also been shown to reduce cravings).



In Health Canada’s product monograph for semaglutide 2.4mg, an important point is that there is not a weight-based stopping rule, whereas older obesity medication product monographs issued by Health Canada have advised discontinuation of weight management medication if 5% weight loss is not achieved.  This is an important step forward, as weight management is about improvement in health (not the numbers on the scale), and because defining success of a medication also depends on a person’s prior weight trajectory.  For example, if a person had lost weight with lifestyle changes prior to starting weight management medication, and the medication helps to prevent weight regain, this is considered a success of treatment (as per our Canadian Obesity Guidelines recommendation).  Or, if a person had been gaining weight prior to using weight management medication, and medication helps to prevent further weight gain, I would consider this a successful treatment as well.


Semaglutide 2.4mg is taken once a week, subcutaneously (under the skin) using a tiny needle.  In terms of common side effects, about 20% of people can get gastrointestinal upset, mostly early on in treatment.  This can include nausea, diarrhea, constipation, heartburn, and/or vomiting.  Recently, my colleagues and I published a paper on how to manage gastrointestinal side effects that can be seen with the GLP1 receptor agonist class.


In terms of rare side effects, I counsel my patients that there is about 1% chance of getting gallstones over and above the risk of gallstone formation from weight loss alone.  I also advise that there is about 1 in 1000 per year chance of pancreatitis.


While semaglutide 2.4mg is now approved in Canada, it won’t be on shelves until later in 2022, due to existing demand in the USA where it’s already in use.


Semaglutide at a lower dose of 1mg weekly (trade name Ozempic) has been in use in Canada as a type 2 diabetes treatment since early 2018.  It is broadly used in type 2 diabetes treatment as it has been shown to provide impressive improvement in blood sugars, weight loss, and importantly, reduces the risk of cardiovascular events (heart attacks and strokes) in people with type 2 diabetes.


Semaglutide 2.4mg is now being studied in people with obesity and a history of cardiovascular disease, without diabetes, to see if it can reduce cardiovascular events in this high risk group.


BOTTOM LINE:  Semaglutide 2.4mg weekly is an important advance in the field of obesity medicine, with important health benefits, and showing greater weight loss than any other approved treatment.


Disclaimer: I am an investigator and coauthor of several studies/substudies in the STEP clinical trial program. I receive honoraria as a continuing medical education speaker and consultant from the maker of semaglutide and liraglutide (Novo Nordisk), and naltrexone/bupropion (Bausch).