Mounjaro is more effective for weight loss than Ozempic. How does it work? And why does it cost so much?

A weight loss drug more effective than Ozempic and Wegovy it was recently approved in Australia.

The drug tyrzepatid, sold under the brand name Mounjaro, affects the feeling of hunger and satiety and also changes the way the body processes food. (In other countries, tyrzepatid is also available under the brand name Zepbound.)

So what does tirzepatid work and how is it different from Ozempic? And with prices ranging from $315 to $645 per month for a starting dose, why is it so costly?

How does it work?

Think of tirzepatid as a master key that unlocks two essential doors in your weight management system. It mimics two hormones: GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide).

When you eat, your body naturally releases the hormones GIP and GLP-1. These hormones play a key role in regulating appetite, food intake and blood sugar levels. Tirzepatid mimics and enhances the effects of these hormones.

By mimicking the hormones GLP-1 and GIP, tirzepatid makes people feel fuller with smaller meals. This can reduce your overall food intake and over time lead to weight loss.

It also helps the body process sugar more efficiently and slows the speed at which food leaves the stomach. This means you eat less, feel full for longer, and have healthier blood sugar levels.

How does it compare to Wegovy/Ozempic?

Tirzepatid (Mounjaro) and semaglutide (Wegovy/Ozempic) are similar in many ways. Both are injectable medications used for weight loss and work by mimicking hormones that regulate appetite and blood sugar levels.

The key difference is that tirzepatide acts on two hormone receptors (GIP and GLP-1), while semaglutide only acts on one (GLP-1). This dual action is believed to be the reason why tirzepatid has shown slightly better weight loss results in clinical trials.

Clinical trials showed that participants lost an average of 25% of body fat in the first year of tirzepatide treatment. This was combined with lifestyle advice from a health care professional who encouraged a robust, low-calorie diet (500 fewer calories per day compared to the patient’s diet at the start of the study) and at least 150 minutes of physical activity per day.

For comparison, weight loss averages 15% in the first year. semaglutidealso in combination with a reduced-calorie diet (500-calorie deficit per day) and increased physical activity (150 minutes per week).

For a person weighing 120 kg, this could mean the difference between losing 30 kg with tirzepatide and 18 kg with semaglutide. But of course, with both drugs, some people will lose less weight than average, some will lose more, and some may not respond to the drug at all.

What are the side effects of tirzepatide?

Like every drug, tyrzepatid has side effects. The most common are nausea, vomiting, diarrhea and constipation. These may resemble soft stomach discomfort and are similar to those seen with semaglutide.

For most people, these side effects are manageable and often go away over time.

There are also rarer and more sedate threats to consider. These include inflammation of the pancreas and gallbladder problems. There is also a potential increased risk of, among others: thyroid canceralthough so far this has only been observed in laboratory rats, not humans.

As with Ozempic and Wegovyonce you stop taking tirzepatide, its effect will stop. Very people recover some, if not all, of the weight lost.

Who can access tirzepatid?

In Australia, tirzepatide is approved for utilize in adults with a body mass index (BMI) of 30 or higher, or a BMI of 27 or higher if you have weight-related conditions such as diabetes. It can only be prescribed by a doctor after trying other weight loss methods.

But this is not suitable all. It should not be used during pregnancy and may not be suitable for people with certain medical conditions or those with a history of eating disorders.

If you are considering tirzepatid, it is essential to discuss the benefits and risks to your personal health with your doctor.

Why is it so costly?

Tirzepatid usually costs around AUD 345 per month for the starting dose. This can escalate to $645 per month for a fixed “maintenance” dose if: a higher dose is necessary for the treatment of diabetes and/or weight control. This puts the drug out of reach for most people.

Tirzepatid, sold in Australia as Mounjaro, is available by prescription only and is not subsidized by the Pharmaceutical Benefits Scheme (PBS). This means you pay the full cost of the drug without any government support.

However, the UK recently announced that it will gradually introduce tyrzepatid into the national health service over the next three years, so it is possible that it will be subsidized in Australia in the future.

Developing up-to-date drugs is an costly business. Companies spend billions on research, clinical trials and regulatory approvals. They then set high prices to recoup those costs and make a profit.

The patent for tyrzepatid is ongoing until 2036. So we won’t have any cheaper generic versions for over a decade.