Is the ‘Godzilla’ weight loss jab REALLY the best? MailOnline’s graphic reveals all… and how it truly compares against rivals Ozempic and Mounjaro

A new weight loss vaccine nicknamed ‘Godzilla’ could be the best yet, research suggests.

Exciting trials of the drug retatrutide found it helped people lose a quarter of their body weight in less than a year.

Unlike other slimming injections, retatrutide not only suppresses appetite but also speeds up metabolism.

However, is it the most effective? A fascinating chart from MailOnline shows exactly how it compares to its competitors.

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Semaglutide

Semaglutide, sold under the brand names Ozempic and Wegovy, mimics a hormone called GLP-1 that makes you feel full.

Ozempic is currently only available on the NHS to manage blood sugar levels in patients with type 2 diabetes.

Its spectacular slimming effects, demonstrated in trials and real-world scenarios, have led doctors and pharmacists to offer it “off-label” to people wishing to lose weight.

Health chiefs, however, have repeatedly insisted against the practice due to supply issues, warning it puts the lives of diabetics at risk.

Wegovy, containing the same active ingredient, was approved last year specifically for weight loss. Although it is also hit by global shortages.

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Trials key to the approval of Novo Nordisk’s semaglutide show it can help users lose up to 15 percent of their body weight over 68 weeks.

A month’s supply is available privately from Boots and Superdrug for around £200.

The eligibility criteria for people wanting to get the drug on the NHS – for the standard prescription rate of £9.90 in England – are strict.

And medications are not without side effects.

Users commonly complain of nausea, constipation, and diarrhea after taking the medication.

Tirzepatid

Mounjaro, as its name suggests, also mimics GLP-1, as well as a second appetite-controlling hormone called GIP.

Studies have shown that the drug, made by US pharmaceutical giant Eli Lilly, could help obese people lose up to 22.5% of their weight in 72 weeks.

It is self-injected once a week, just like semaglutide.

The stark difference in results led US diabetes expert Dr Julio Rosenstock to declare Mounjaro “King Kong” compared to rival Wegovy’s “gorilla”.

Some patients already taking the drug have shared their results on social media, with one overweight man saying it helped him lose 100 pounds.

Similar to semaglutide, side effects of tirzepatide (generic name Mounjaro) include nausea, diarrhea, vomiting – which usually goes away over time – and constipation.

It was given the green light from the National Institute of Excellence in Health and Care (Nice) for NHS to be used in September for patients with type 2 diabetes who are not controlling their condition.

It is not yet used by health services for obesity.

But in February it was made available privately in Britain, with clinics charging around £40 for a week’s supply.

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Retatrutide

Retatrutide, on the other hand, adds a third hormone called glucagon, which triggers the body to burn more fat, thereby increasing the rate of calorie burning.

The results of the trial, presented yesterday at the European Obesity Congress in Venice, showed that this method achieved an even greater average weight loss – 24 percent of body weight – over a shorter period of 48 weeks.

Its phase two study of 338 obese people also found that the results were even more striking in women, helping them lose 28.5 percent of their body weight.

In comparison, men lost an average of 21.2 percent.

And obese participants lost an even higher percentage of their body weight, 26.5 percent in 48 weeks.

Unusually, 100 percent of trial participants lost at least 5 percent.

Like all previous GLP-1 drugs, retatrutide – taken once a week – caused side effects including nausea, diarrhea and constipation.

But the study, published in the New England Journal of Medicine, shows the drug has other health benefits as well.

Participants saw significant improvements in their blood pressure and blood sugar levels. Four out of ten participants were able to stop their blood pressure medications.

Manufactured by American pharmaceutical company Eli Lilly, larger-scale trials are currently underway with results expected in 2026.

This means the treatment could be available on the NHS within around three years, pending final regulatory hurdles.

Orlistat

Orlistat is a pill already available on the NHS for weight loss.

Taken up to three times a day with a meal, it prevents the absorption of fats by the digestive system.

Undigested fat is passed from the body in the form of stool.

Although it stops people from gaining more weight, it doesn’t help them lose it in itself.

Side effects include fatty or oily poops, oily discharge from the rectum, and high levels of flatulence.

Manufactured by pharmaceutical giant Roche, early studies suggest patients taking 120 mg could lose up to 10.3 kg (22.7 pounds) in 52 weeks.

Its prescribing on the NHS is limited to those who are obese or overweight and have another health problem such as high blood pressure.

Liraglutide

Sold under the Saxenda brand, the daily self-administered vaccine is another weight loss treatment already available in health services.

It works in a similar way to semaglutide by changing the body’s metabolism, making people feel full and less hungry.

This causes them to eat less and, in theory, lose weight.

Saxenda, however, is among a number of similar drugs that are experiencing a supply shortage globally.

Liraglutide is usually only prescribed on the NHS after a GP has referred you to a specialist weight loss management service and when orlistat has not worked.

Side effects include aches, pain, diarrhea, fever, frequent urination, and trouble sleeping.

Made by Novo Nordisk, trials have shown that users lose an average of 6.4 percent of their body weight over 68 weeks.