Mounjaro vs Wegovy: From side effects to max weight loss, how top fat jabs compare – as price hike looms

The Sun

2 days ago

WITH the price of Mounjaro set to rise and concerns about long-term affordability and access, many may be looking to turn to alternative treatments, like Wegovy.
But how do the two weight loss jabs compare in their success, side effects and price?
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People paying privately for Mounjaro in the UK face a rise in the cost of treatment after manufacturer Eli Lilly announced on Thursday it was increasing the list price by as much as 170 per cent.
The change means the suggested price for a month's supply of the highest dose of the medicine will increase from £122 to £330 (for the provider).
While retailers who sell Mounjaro may be able to negotiate discounts, it's likely the price will increase at least somewhat for the estimated 1.5 million people on weight loss drugs in the UK.
GP Dr Ross Perry, medical director of Cosmedics skin clinics, is one of a number of medics who predict the price change will influence patient choice over what and which weight loss treatment to opt for.
Mounjaro and Wegovy are similar in that they both belong to a group of medications called glucagon-like peptide 1 (GLP-1) receptor agonists. But there are a host of differences between the two.
Dr Perry says: "Wegovy has a longer track record for weight loss and might be seen as a safer, more established option, but if Mounjaro becomes significantly more expensive, some patients may opt for Wegovy to save money, even if Mounjaro could deliver slightly greater weight loss.
Our experts share the main differences between Mounjaro and Wegovy to be aware of that may influence whether you make the switch.
What are the main differences?
While both Wegovy and Mounjaro are injectable weight loss medications, they work slightly differently.
Professor Franklin Joseph, head of Dr Frank's weight loss clinic, explains: "Wegovy contains semaglutide, which mimics a hormone called GLP-1 that slows digestion, reduces appetite, and helps regulate blood sugar.
"Mounjaro contains tirzepatide, which mimics GLP-1 but also another hormone called GIP.
"That dual action appears to be the mechanism that gives Mounjaro a slightly stronger effect on appetite control and weight loss.'
Do you take different doses?
Wegovy and Mounjaro are both weekly injections intended for long-term use, but have different dosing schedules.
Wegovy starts at 0.25mg weekly and is gradually increased to a maintenance dose of 2.4 mg, while Mounjaro begins at 2.5 mg weekly and can be stepped up to a maximum of 15 mg.
This does not necessarily mean Mounjaro users start and end on the highest dose. The dosages are not directly comparable because they are different ingredients.
"Neither is designed as a short-term treatment," says Dr Perry. "They are ongoing therapies for managing weight and, in some cases, blood sugar.
"As long as they remain effective and side effects are manageable, they can be taken for years under medical supervision.
"Stopping the medication often makes it harder to maintain weight loss and blood sugar control."
Which one can help you lose more weight?
Studies so far suggest Mounjaro may be more effective than Wegovy for weight loss.
In clinical trials called 'SURMOUNT', sponsored by Eli Lilly, people on Wegovy lost around 15 per cent of their body weight on average over about 68 weeks, while those on Mounjaro lost up to 21 per cent in a similar time frame.
"This is likely because Mounjaro works on two hormones (GLP-1 and GIP) instead of just one," says Dr Perry.
But Professor Joseph adds: "Both are very effective compared to lifestyle measures alone, and the response can be very individual, with dramatic and life-changing weight loss occurring with both medications."
For Toby Nicol, CEO of CheqUp, which provides weight loss injections, Mounjaro is the more effective medication.
He says: "Both drugs are excellent for weight loss, but one way of looking at this is to consider that Mounjaro is a Ferrari, Wegovy is a Porsche, but the alternative (diet and exercise) is a horse and cart.'
How do side effects differ?
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Wegovy and Mounjaro share most of the same side effects because they work in similar ways. These mainly affect digestion, says Dr Perry.
Common issues include nausea, vomiting, diarrhoea, constipation, and stomach pain or bloating.
"The main difference is Mounjaro's dual action can sometimes make these effects feel stronger, especially in the early stages or when doses are increased," Dr Perry explains.
"Some people also notice greater appetite suppression or changes in taste with Mounjaro.
"But serious side effects, such as gallbladder problems or pancreatitis, are rare but possible with both medications."
Clinical trials have also shown that Wegovy has a higher rate of nausea.
Dr Perry says: "Forty-four per cent of users experience it, but only about 12 per cent of Mounjaro users report nausea."
Is one better suited to certain people than the other?
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Wegovy and Mounjaro are both suitable for adults with obesity or those who are overweight with weight-related health problems, but there are some differences in how they're typically prescribed.
Dr Perry explains: "Wegovy is widely approved specifically for weight management, so it's often the first choice for people without diabetes who want a proven option with a longer safety track record in weight loss.
"It may also be preferred for patients who are sensitive to stronger appetite suppression or digestive side effects.
"Mounjaro was first approved for type 2 diabetes, so it's often prescribed to people who have both obesity and diabetes or prediabetes, as it can offer powerful blood sugar control alongside weight loss.
"It's newer for obesity treatment, but may be chosen for people who want the potential for greater weight loss or who haven't achieved enough results with a GLP-1–only drug like Wegovy."
Prof Joseph adds: " In the end, the choice often comes down to cost, availability, side effect tolerance, and a discussion between doctor and patient.'
As to whether Prof Joseph thinks patients will make the switch from Mounjaro to Wegovy, he says: "Cost will definitely play a role.
"These treatments are very expensive, and if Mounjaro becomes significantly pricier, many patients may switch to Wegovy, especially if their weight loss has been steady and they're tolerating it well.
"For those who can afford it, Mounjaro's extra effectiveness may justify the higher price, but most patients are very cost-sensitive, so we're likely to see more people choosing Wegovy.'
The Mounjaro announcement doesn't affect the price the NHS pays, as the service has negotiated a heavily discounted rate for those getting the drug on prescription.
Find out if you could be eligible below...