Science behind ‘most powerful weight-loss jab ever’ dubbed 'Godzilla of weight loss'

Outta the way Ozempic, watch out Wegovy, and move over Mounjaro because a new weight loss colossus is on the market.

These so-called 'skinny jabs' remain all the rage, but with more companies popping up, prices being driven down, and new ways to take GLP-1s, patients are looking for increasingly bigger and better things in hopes of trimming down to sculpt that summer body.

As hard as we might try, the reality is that some of us are never going to have a body like Chris Evans' Captain America or Angelina Jolie's Lara Croft, but does that really matter? Even though beauty is in the eye of the beholder, many continue to look for alternative ways to lose weight when their 1,000th diet and six-day-a-week gym trips just don't seem to be paying off.

Our health is more important to us than ever in 2026, and despite there being continued concerns about the use of Ozempic and other GLP-1s in terms of side effects that range from blindness to even potential cases of death, others bill these as potential miracle cures that can be used for far more than just weight loss or treating type 2 diabetes.

Coming in the aftermath of exciting developments in the form of new GLP-1 pills for those who are afraid of needles, Eli Lilly is making big moves with retatrutide.

What is retatrutide?

Eli Lilly is currently undergoing Phase 3 clinical trials for retatrutide, targeting obesity and type 2 diabetes with its latest jab. Described as the 'Godzilla' of weight loss jabs, one major trial involved 2,300 adults who were classed as overweight. When placed on the highest dose, they lost an average 28.3% of their body weight, with some losing up to five stone. With over half losing 30% of their body weight, these almost unheard of results are typically only related to weight loss surgery. As we know, weight loss surgery can be expensive, dangerous, and scary, with retatrutide offering a potential alternative.

With Eli Lilly cheering the results, Kenneth Custer, Ph.D., executive vice president and president, Lilly Cardiometabolic Health, said: "From the 4 mg dose, reaching nearly 20% weight loss with one escalation step, to the 12 mg dose that delivered a level of weight loss long associated with bariatric surgery, retatrutide offers the potential for a patient-centric approach to obesity.

“Together with Zepbound and Foundayo, retatrutide could build on Lilly's commitment to match treatments to the needs and preferences of patients."

This was echoed by Ania Jastreboff, M.D., Ph.D., Professor of Medicine & Pediatrics (Endocrinology) at the Yale School of Medicine, Director of the Yale Obesity Research Center (Y-Weight), and lead investigator. Jastreboff added: "Obesity is a chronic disease, and people living with obesity deserve treatment options that match the complex biology of their neurometabolic disease..."Importantly, treatment with retatrutide not only resulted in robust weight reduction, but also in clear improvements in assessed cardiometabolic health measures."

She concluded that retatrutide could revolutionize things for her patients, referring to it as a "highly impactful future tool to treat their obesity and transform their health trajectory."

How does retatrutide work?

In a National Library of Medicine report,retatrutide is described as a triple receptor agonist that targets glucagon-like peptide-1 (GLP-1), Glucose-Dependent Insulinotropic Polypeptide (GIP), and glucagon receptors. This is where it gets its 'triple G' moniker, using a multi-pathway mechanism to target appetite suppression and blood sugar control, while also elevating calorie burning for that extra pizazz. We all know that typical GLP-1 jabs tend to make you feel fuller for longer, but the GIP pathway lowers blood sugar levels and helps regulate how your body stores and metabolises fat cells. In terms of burning fat, the glucagon pathway activates the receptor that breaks down stored body fat through lipolysis, effectively telling the body to burn more calories even when it's resting.

It's this part of retatrutide that sets it apart from other single or dual-target medications that are already on the market.

In the first two phases of trials, Eli Lilly noted dose-dependent weight loss, a reduction in Glycated Hemoglobin (HbA1c) levels, and an improvement in liver steatosis and diabetic kidney disease.

As with all of these things, there are some expected side effects, with early trials linking retatrutide to gastrointestinal issues. Still, the report concluded that "retatrutide heralds a new era in obesity and T2DM treatment, offering hope for improved patient outcomes."