Weight loss is a common goal for many people, but for some, diet and exercise alone may not be enough to achieve the desired results. In such cases, weight loss medications can play a supportive role as part of a medically guided, comprehensive weight management plan.
Among the most popular and widely discussed medications today are Ozempic, Wegovy, Saxenda, and Mounjaro. While all four belong to a class of drugs known as GLP-1 receptor agonists (with Mounjaro having dual-action as a GIP/GLP-1 agonist), each has unique features in terms of effectiveness, dosage schedule, FDA-approved uses, and suitability for different patients.
In this article, we’ll compare the benefits, mechanisms, dosing, and side effects of these medications—helping you understand how they work and which one might be the right option for your weight loss journey.
Meet the GLP-1 Agonists: Saxenda, Wegovy, Ozempic, and Mounjaro
Saxenda, Wegovy, Ozempic, and Mounjaro are part of a powerful group of medications known as GLP-1 receptor agonists—a class originally developed to help manage type 2 diabetes, but now widely used (and FDA-approved in many cases) for medical weight loss.
GLP-1 stands for glucagon-like peptide-1, a naturally occurring hormone produced by the intestines. This hormone plays a key role in regulating blood sugar, appetite, and digestion. GLP-1 agonists work by mimicking the effects of this hormone, resulting in several beneficial metabolic actions:
- Stimulate insulin secretion from the pancreas in response to meals
- Suppress appetite by acting on appetite centers in the brain
- Slow gastric emptying, which helps prolong satiety after eating
- Reduce glucagon secretion, helping to lower blood sugar levels
Together, these effects make GLP-1 agonists an effective tool not only for diabetes management but also for sustainable, medically supervised weight loss. With varying dosing schedules, effectiveness, and additional mechanisms of action (like Mounjaro’s GIP activity), each medication offers unique advantages.
In the following sections, we’ll break down how each one compares—so you can better understand which may be right for your goals.
Comparing the Top GLP-1 Agonists: Saxenda vs Wegovy vs Ozempic vs Mounjaro.
| Medication | Active Ingredient | FDA Approval | Dosing Frequency | Approved Use | Average Weight Loss | Special Feature |
|---|---|---|---|---|---|---|
| Saxenda | Liraglutide | ✔️ Obesity | Daily injection | Weight loss (BMI ≥30 or ≥27 with comorbidities) | ~5–8% body weight | First GLP-1 approved for obesity |
| Wegovy | Semaglutide | ✔️ Chronic weight management | Weekly injection | Weight loss (BMI ≥30 or ≥27 with comorbidities) | ~15% body weight | Higher-dose semaglutide for weight |
| Ozempic | Semaglutide | ✔️ Type 2 Diabetes | Weekly injection | Blood sugar control (off-label for weight loss) | ~10–14% body weight | Most accessible GLP-1 worldwide |
| Mounjaro | Tirzepatide | ✔️ Type 2 Diabetes | Weekly injection | Blood sugar control (off-label for weight loss) | ~22% body weight | Dual GLP-1 + GIP action; superior weight loss in trials |
Semaglutide vs. tirzepatide
Semaglutide is the active ingredient in Ozempic and Wegovy. It works as a GLP-1 receptor agonist to treat type 2 diabetes. People also use it to help them lose weight. Tirzepatide is the active ingredient in Mounjaro and Zepbound, which also can treat type 2 diabetes and encourage weight loss. Tirzepatide is a GLP-1 receptor agonist, too. But it also works in a second way, as what’s known as a GIP receptor agonist. GIP, short for glucose-dependent insulinotropic polypeptide, is another hormone your body makes after you eat.
So both semaglutide and tirzepatide work by acting like hormones your body normally makes after you eat. They can make your stomach empty more slowly so that you won’t want to eat again as soon. They also send signals to the brain that tell you you’re full. The main difference is that tirzepatide mimics two hormones while semaglutide mimics one.
Weight Loss Effectiveness – What the Research Shows
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.
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.
How do I use Saxenda?
Saxenda is given as a subcutaneous injection once daily, under the skin of the stomach, thigh, or upper arm.
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.
What are the common side effects of Saxenda?
Nausea, vomiting and diarrhoea are some of the most common side effects.
WEGOVY (semaglutide)
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.
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.
What are the common side effects of Wegovy?
Nausea, vomiting, diarrhoea, stomach pain, constipation and headache are among the most common side effects.
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.
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)
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.
What are common side effects of Ozempic?
Nausea, vomiting, diarrhoea, stomach pain, constipation and headache.
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.
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.
How do I use Mounjaro?
Mounjaro is given as a subcutaneous injection once weekly, under the skin of the stomach, thigh, or upper arm.
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.
Dosing and Administration
| Medication | Starting Dose | Maintenance Dose | Frequency |
|---|---|---|---|
| Saxenda | 0.6 mg/day | 3.0 mg/day | Daily |
| Wegovy | 0.25 mg/week | 2.4 mg/week | Weekly |
| Ozempic | 0.25 mg/week | 0.5–2.0 mg/week | Weekly |
| Mounjaro | 2.5 mg/week | 5–15 mg/week | Weekly |
Side Effects – What You Should Know
Common side effects across all medications:
- Nausea
- Vomiting
- Diarrhea
- Constipation
- Headache
Mounjaro may have slightly more gastrointestinal side effects due to dual hormone action.
Note: Always consult a healthcare provider before starting these medications, especially if you have a history of pancreatitis or thyroid cancer.
Cost Comparison
| Medication | Estimated Monthly Cost (THB) |
|---|---|
| Saxenda | THB 14,000 |
| Wegovy | THB 15,800 |
| Ozempic | THB 17,000 |
| Mounjaro | THB 16,000 |
So, Which Is Better for Weight Loss?
- Choose Mounjaro if: You want the most weight loss possible and can access it via insurance or private pay.
- Choose Wegovy if: You need an FDA-approved, semaglutide-based weight loss option with strong results.
- Choose Ozempic if: You’re looking for a more affordable semaglutide option off-label.
- Choose Saxenda if: You prefer daily injections or have contraindications to semaglutide or tirzepatide.
Final Thoughts
The best medication for weight loss depends on your goals, health history, budget, and your body’s response to treatment. Always consult with a healthcare provider to determine the most appropriate option. With proper guidance, any of these medications can help support your journey toward healthier weight and better metabolic health.
