While Ozempic is the blockbuster medication everyone’s talking about weight loss, the active ingredient – semaglutide – is part of a class of medications that work in a similar way. This medication family is known as GLP-1 agonists, and in addition to Ozempic, include Saxenda, Wegovy (which is also semaglutide) and Mounjaro which are already being prescribed “off label”. When a medication is prescribed for something other than its approved usage under the Pharmaceutical Benefits Scheme, it’s called off label prescribing. Wegovy which is simply a rebranded semaglutide specifically studied for weight loss, is yet to arrive in Australia. For people with obesity who struggle to “feel full”, GLP-1 agonists can help in restoring better control over appetite.1
But how do each of these medications compare, and which one is right for you?
This is what to know ahead of talking with your GP.
What are GLP-1 agonists?
Also known as glucagon-like peptide-1 receptor agonists, the GLP-1 drug class includes prescription medications that are used to treat type 2 diabetes mellitus (T2DM) and obesity.1 These medications work by mimicking the action of the body’s own GLP-1 hormone that helps to regulate blood sugar levels and manage appetite.2
Ozempic is a GLP-1 agonist
Ozempic (semaglutide) is the best known GLP-1 agonist medicine but it’s not the only one.3 As interest in this drug class grows globally, more of these medications are being developed. Each differs in its chemical structure, dose, frequency of use and side effects.1
How do GLP-1 agonists assist with weight loss?
Medicines in this drug class stimulate the pancreas to produce more insulin which improves the uptake of glucose from food.1-3 They also decrease the release of glucagon, a hormone that raises blood sugar levels, as well as slowing the rate at which food is digested.1-3 Together, the various effects of GLP-1 agonists can keep you feeling fuller for longer, potentially reducing overall calorie intake which can lead to weight loss.1-3
Which weight loss medication gives the best results?
In general, the longer-acting GLP-1 agonists which are injected weekly, such as semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro), are associated with greater weight loss than the shorter-acting GLP-1 agonists such as liraglutide (Saxenda).4-9
We trawled through studies to compare the results, with the findings as follows:
- Liraglutide (Saxenda): 63.2% of study participants lost at least 5% body weight.4
- Semaglutide (Ozempic, Wegovy): 86.4% of study participants lost at least 5% body weight.5
- Tirzapetide (Mounjaro): 85% of study participants lost at least 5% body weight.6
brochure (aka a Consumer Medicine Information (CMIs)) on our Medication database
What’s special about Mounjaro?
As the newest GLP-1 agonist, Mounjaro works in the same way as Ozempic/Wegovy and Saxenda but has an additional action that maximises insulin sensitivity, potential leading to added weight loss benefits.9 In a 2022 study on Mounjaro found that 85% of participants had a weight reduction of 5% or more over 72 weeks of use and those on the highest dose (15 mg) achieved the biggest lose: -23.6kg, versus -2.4kg with the placebo.6
Related Posts
How will my doctor decide if a GLP-1 agonist is right for me?
If you are considering whether medication-assisted weight loss may be appropriate for you, talk to your GP. They will consider your weight loss goals, your medical history, any comorbidities (other illnesses you may have) and whether medication in tandem with lifestyle modifications could be useful to you.
GLP-1 agonists are not appropriate for everyone who wants to lose weight. You should not take them if you have type 1 diabetes, diabetic ketoacidosis, or a history of pancreatitis. You should also not take them if you are pregnant or breastfeeding.
Lastly, keep in mind that most studies showing efficacy of GLP-1 agonists for weight loss usually require participants to make lifestyle modifications such as changes in diet and exercise, to control portions and eat high nutrient, low energy foods and move more while taking the medications.1
Here’s what to know about the various GLP-1 agonists…
OZEMPIC (semaglutide)
Ozempic was launched in 2017 by the Danish pharmaceutical company Novo Nordisk which also manufactures other diabetes medicines including insulin and Saxenda (liraglutide).10
How do I use Ozempic?
Ozempic is given as a subcutaneous injection once a week, under the skin of the stomach, thigh or upper arm.11-12
What are common side effects of Ozempic?
Nausea, vomiting, diarrhoea, stomach pain, constipation and headache.11-12
What is the dose of Ozempic?
Initially it’s 0.25mg once a week for four weeks. After that, if tolerated and under the supervision of your prescriber, the dose can be increased to 0.5mg once a week for four weeks and then up to 1 mg once a week.11-12
How much does Ozempic cost?
Using Ozempic for weight loss is considered an unofficial, “off-label” indication so your doctor will write your prescription as private. This means it’s not available for PBS subsidy so you’ll likely pay around $130 for each dispensing which can last around a month.
WEGOVY (semaglutide)
Yes, Wegovy is the same semaglutide medication as Ozempic and it’s from Novo Nordisk too. The difference is in the way Wegovy is packaged to deliver a higher dose specific to weight loss rather than diabetes control. While Wegovy is approved by the Therapeutic Goods Administration for use in the management of obesity, it’s not yet available in Australia due to global shortages of semaglutide.13
How do I use Wegovy?
Just like Ozempic, Wegovy is given as a subcutaneous injection once a week, under the skin of the stomach, thigh, or upper arm.4-5
What are the common side effects of Wegovy?
Nausea, vomiting, diarrhoea, stomach pain, constipation and headache are among the most common side effects. 4-5
What is the dose of Wegovy?
Initially it’s 0.25mg once a week for four weeks. After that, if tolerated and under the supervision of your prescriber, the dose can be slowly increased up to 2.4 mg once a week. 4-5
How much does Wegovy cost?
Because Wegovy is not yet available in Australia, its cost is unknown. Don’t expect it to be any less expensive than the other GLP-1 medications which can cost between $130 and $600 per month.
SAXENDA (liraglutide)
The first GLP-1 medication, Saxenda (liraglutide) was launched in 2010 by the same Danish pharmaceutical company Novo Nordisk which manufactures other diabetes medicines including insulin and Ozempic.14
What makes Saxenda different to other GLP-1 agonists?
Unlike Ozempic, liraglutide is officially indicated in Australia for use in weight loss. According to the Australian Medicines Handbook, liraglutide can be used as an “adjunct to lifestyle modification in obesity (BMI >30) or in overweight people (BMI >27) with at least 1 weight-related comorbidity.15
How do I use Saxenda?
Saxenda is given as a subcutaneous injection once daily, under the skin of the stomach, thigh, or upper arm.15
What is the dose of Saxenda?
Initially it’s 0.6mg once daily, increasing each week by 0.6mg, if tolerated and under the supervision of your prescriber, up to a maximum of 3mg daily.15
What are the common side effects of Saxenda?
Nausea, vomiting and diarrhoea are some of the most common side effects.15
How much does Saxenda cost?
Even though Saxenda is indicated for weight loss in Australia, it’s not subsidised by the PBS so the prescription will be written as private. You’ll likely pay around $400 for each dispensing which can last around a month.16
MOUNJARO (tirzapetide)
Newly launched in Australia in late 2023, Mounjaro was released in other countries in 2022 by US pharmaceutical giant Eli Lilly and Company.17
How do I use Mounjaro?
Mounjaro is given as a subcutaneous injection once weekly, under the skin of the stomach, thigh, or upper arm. 6,9,15
What is the dose of Mounjaro?
Initially, it’s 2.5mg once a week for four weeks. If tolerated and under the supervision of your prescriber, your dose may be increased to 5mg weekly then after a further four weeks, it may be increased by another 2.5mg up to a maximum dose of 15 mg once weekly.6,9,15
How much does Mounjaro cost?
Mounjaro is not approved by the TGA for weight loss and not subsidised by the PBS for any indication in Australia. You’ll likely pay around $600 for each dispensing which can last around a month.17
When will Mounjaro be available in Australia?
The TGA recently reported reported that “all strengths of Mounjaro (tirzepatide) will be limited until 31 August 2024 due to unexpected high demand”.1
References
1. Jeong D, Priefer R. Anti-obesity weight loss medications: Short-term and long-term use.
Life Sciences. 2022: 306. doi:10.1016/j.lfs.2022.120825.
2. Australian Medicines Handbook. Glucagon-like peptide‑1 analogues. July, 2023. Accessed December 1, 2023. https://amhonline-amh-net-au.eu1.proxy.openathens.net/chapters/endocrine-drugs/drugs-diabetes/glucagon-like-peptide-1-analogues
3. Australian Medicines Handbook. Semaglutide. July, 2023. Accessed December 1, 2023. https://amhonline-amh-net-au.eu1.proxy.openathens.net/chapters/endocrine-drugs/drugs-diabetes/glucagon-like-peptide-1-analogues/semaglutide?menu=vertical
4. Suran M. As Ozempic’s popularity soars, here’s what to know about semaglutide and weight loss. JAMA. 2023;329(19):1627–1629. Accessed November 13, 2023. doi:10.1001/jama.2023.2438
5. Phillips A, Clements J. Clinical review of subcutaneous semaglutide for obesity. J Clin Pharm Ther.2022;47;2:184–93. Accessed November 13, 2023. doi:10.1111/jcpt.13574
6. Jastreboff AM, Aronne LJ, Ahmad NN, Wharton S, et al. Tirzepatide once weekly for the treatment of obesity. N Engl J Med. 2022; 387:205–216. Accessed November 30, 2023. https://pubmed.ncbi.nlm.nih.gov/35658024/
7. Pi-Sunyer X, Astrup A, Fujioka K, et al. A randomized, controlled trial of 3.0mg of liraglutide in weight management. N. Engl. J. Med. 2015:373(1);11–22. doi:10.1056/NEJMoa1411892.
8. Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity. N. Engl. J. Med. 2021:384(11);989. doi.org/10.1056/NEJMoa2032183.
9. Chavda VP, Ajabiya J, Teli D, Bojarska J, Apostolopoulos V. Tirzepatide, a new era of dual-targeted treatment for diabetes and obesity: a mini-review. Molecules. 2022 Jul 5;27(13):4315. doi: 10.3390/molecules27134315.
10. Novo Nordisk. Ozempic. [nd]. Accessed November 13, 2023. https://www.ozempic.com
11. Ozempic Consumer Medicine Information (CMI) summary. Accessed November 13, 2023. https://www.ebs.tga.gov.au/ebs/picmi/picmirepository.nsf/pdf?OpenAgent&id=CP-2020-CMI-01750-1&d=20231114172310101
12. Semaglutide. Australian Medicines Handbook. July, 2022. Accessed November 14, 2023. https://amhonline-amh-net-au.eu1.proxy.openathens.net/chapters/endocrine-drugs/drugs-diabetes/glucagon-like-peptide-1-analogues/semaglutide#semaglutide-dosage
13. Therapeutic Goods Administration. About the Ozempic (semaglutide) shortage 2022 and 2023. September 21, 2023. Accessed November 11, 2023. https://www.tga.gov.au/safety/shortages/information-about-major-medicine-shortages/about-ozempic-semaglutide-shortage-2022-and-2023
14. Australian Government Department of Health and Aged Care. Liraglutide (rys), injection solution, pre-filled pen, 6 mg per mL, 3 mL, 2 and 3 pen pack, Victoza® – November 2011. The Pharmaceutical Benefits Scheme. March 02, 2012. Accessed December 1, 2023. https://www.pbs.gov.au/info/industry/listing/elements/pbac-meetings/psd/2011-11/pbac-psd-liraglutide-nov11
15. Australian Medicines Handbook. Liraglutide. July, 2023. Accessed December 1, 2023. https://amhonline-amh-net-au.eu1.proxy.openathens.net/chapters/endocrine-drugs/drugs-diabetes/glucagon-like-peptide-1-analogues/liraglutide
16. Sweeting AN, Caterson ID. Liraglutide: for obesity, not just type 2 diabetes. Medicine Today. August, 2020. Accessed December 1, 2023.https://medicinetoday.com.au/mt/2020/august/feature-article/liraglutide-obesity-not-just%C2%A0type-2-diabetes
17. Worthington E. Diabetes drug Mounjaro already in short supply months after launching in Australia. ABC News. November 30, 2023. Accessed December 1, 2023. https://www.abc.net.au/news/2023-11-30/mounjaro-weight-loss-diabetes-drug-shortage/103170324
18. Therapeutic Goods Administration. Shortage of Mounjaro (tirzepatide) injections. November 30, 2023. Accessed November 30, 2023. https://www.tga.gov.au/safety/shortages/medicine-shortage-alerts/shortage-mounjaro-tirzepatide-injections
