Choosing the right path for your weight management journey can be confusing, especially considering the new medications available. You might have heard of Mounjaro and Wegovy, but be unsure what the difference is.
Mounjaro and Wegovy have plenty in common. They’re both new and much sought-after medicines for weight loss that are taken in the same way: weekly via an injector pen. And they’ve each been shown to drive serious results for men and women.
Healthy changes to diet and exercise alone might lead to a 1-10% loss (which is still significant!). But when taking one of these medicines as well, people have reported losses of over 15%.
Yet Wegovy and Mounjaro are two separate medications. What sets them apart is how they work. Each has a different active ingredient, meaning that they affect the body in their own way.
So, could one lead to more weight loss than the other? Here’s everything you need to know.
Are Mounjaro and Wegovy the same?
In a word: no. Mounjaro and Wegovy are both used for weight loss alongside changes in diet and exercise, but they’re different medications.
Mounjaro uses the active ingredient tirzepatide, which works by mimicking the actions of two hormones that are naturally released when we eat: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). This signals to the brain that you’re full, which helps you to eat less. It’s available in six different doses, from 2.5mg to 15mg, and is used to treat type 2 diabetes as well.
On the other hand, the active ingredient in Wegovy is semaglutide. It works by copying the effects of GLP-1 - which also suppresses your appetite. Wegovy comes in five doses, from 0.25mg through to 2.4mg.
Active ingredients: Mounjaro vs Wegovy
The active ingredient in a medicine is what makes it work. Here’s how Mounjaro and Wegovy’s compare.
What’s the active ingredient in Wegovy?
That would be semaglutide. It works by copying the effects of GLP-1, which means that it brings on the same effects that the hormone would naturally.
There are a few different ways that GLP-1 works to dial down our appetite.
One is communicating directly with the hypothalamus, a part of the brain involved in regulating food intake. GLP-1 can stimulate specific neurons and prevent the release of particular chemicals to make us feel full.
Another is telling the pancreas to release insulin in response to us eating. The food we eat is broken down by the body into sugar (glucose) that enters the bloodstream. Insulin is then released to shuttle this sugar around the body so it can be used as energy. When insulin rises, this signals to the brain to lower our appetite.
GLP-1 also helps to keep your blood sugar in check by telling the liver to produce less glucose and increasing levels of the adiponectin. This is a hormone released by fat tissues that helps the body become more responsive to the effects of insulin.
Keeping blood sugar under control is important for weight loss because if it’s too high — for example, if you take in more energy than your body needs — the glucose can ultimately be stored as fat.
Finally, semaglutide can slow down digestion, so it takes more time for your stomach to empty — which makes you feel like you’re full for longer.
What’s the active ingredient in Mounjaro?
Tirzepatide suppresses your appetite in the same ways that semaglutide does.
But it does so via the effects of two hormones —GLP-1 and GIP— as opposed to one. This means that tirzepatide is more potent, which explains why it shows stronger results in scientific research. Though that’s not to say that you’d be worse off with semaglutide — it still works very well.
Wegovy vs Mounjaro: what’s more effective?
Studies show that tirzepatide leads to more weight loss than semaglutide. Though both are still considered very effective for weight loss when used alongside healthy lifestyle changes.
In one analysis that looked at over 40,000 electronic health records, people both with and without type 2 diabetes lost an average of 15.3% of their body weight after taking tirzepatide for a year. Those taking semaglutide lost 8.3%.
Other studies show similar results, though there’s limited research comparing the two medicines head-to-head. In a trial of 2,539 adults without type 2 diabetes, people lost 20.9% of their body weight on average after taking 15mg tirzepatide for 72 weeks. For semaglutide, there’s evidence showing a mean loss of 14.9% after taking 2.4mg for 68 weeks.
Tirzepatide has also been found to do a better job of keeping your blood glucose in check than semaglutide.
Heads up: studies can give us an idea of how these medications might work, but there’s no way to know for sure how they will affect you personally. The figures we get from research are based on average results from large groups of people, meaning that some people lost more weight and some lost less.
Who should take Mounjaro or Wegovy for weight loss?
Both Mounjaro and Wegovy are recommended for adults with a BMI of 30 or higher. However, if you have a weight-related health condition, you may qualify for these medications from a BMI of 27. People of certain ethnicities, including South Asian, South-East Asian, Middle Eastern, Black African or African-Caribbean, may qualify with a lower BMI, too.
Neither medicine is meant for people who are breastfeeding or pregnant. You should also speak with your doctor before taking them if you’ve got issues with your digestion or eyesight, have previously had thyroid cancer, or have had problems with your pancreas or kidneys.
Mounjaro vs Wegovy: side effects
Side effects are fairly common with these medicines, but most of the time, they aren’t anything to worry about and go away on their own.
For both Mounjaro and Wegovy, the most commonly-reported symptoms include nausea, diarrhoea, vomiting, and constipation. These affect over one in ten people.
Some people may experience more serious side effects. For both medicines, these include severe pain in the stomach or back which doesn’t go away, which may affect up to one in 100 people. One in a thousand people could have an allergic reaction to the medication (you might have trouble breathing or have a swollen tongue, throat, or lips). See your doctor right away if either of those apply to you.
Taking birth control pills? If you’re starting Mounjaro, either use a barrier method (like a condom) or switch to a non-oral contraceptive for the first four weeks and for four weeks after you increase your dose. This is because it might affect how well contraceptive pills work.
Wegovy vs Mounjaro: how much do they cost?
It depends on where you get your medication from.
The UK list price of 2.4mg Wegovy is £175.80 per pack, which gives you a month’s supply. Doses of 1.7mg are £124.53, while 1.0mg, 0.5mg, and 0.25mg are all £73.25. If you get it through the NHS you’ll either pay nothing or the standard prescription cost of £9.90.
Mounjaro isn’t yet available on the NHS but you can get it via private prescription. According to its provisional list prices, it’s £122 for four weeks’ worth of 12.5mg and 15mg doses; £107 for 7.5mg and 10mg; and £92 for 2.5mg and 5mg.
When you buy from a private provider, you might pay more or less than the above. At Voy, we offer a weight loss programme that includes medication plus support from a dedicated health team, who will help you stay on track through our app - with a money-back guarantee if you don’t lose more than 10% of your body weight within six months.
Your weight loss journey
You’ve taken a major step towards your health goals by exploring which options are right for you. We know that this wasn’t done lightly — considering whether to start a new medication can feel overwhelming or even scary. But we’re so glad you’re here. These medicines could help you reach your goals, but remember: they aren’t “shortcuts”. They’re meant to supplement healthy lifestyle changes, and for best results, most people will need to take them for over a year.
Mounjaro or Wegovy might be a good next step for people who have tried losing weight through diet or exercise, but it didn’t work as well as they’d have liked. And if you feel ready, you can take that step right now. Fill out this short form to find out if our weight loss programme is right for you — it won’t take more than a few minutes. Then, our team of experts will be in touch with a programme that’ll get you on track to reaching your goals.
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