A new weight loss injection, retatrutide, has been developed and is showing remarkable results, surpassing existing options like Ozempic. The drug helps obese patients lose up to four stone in less than a year.
Retatrutide targets three distinct receptors in the brain, which not only enhances calorie burning but also makes individuals feel fuller. Unlike current weight-loss injections, which primarily suppress appetite, this new treatment also accelerates metabolism.
In a trial presented at the European Congress on Obesity in Venice, participants experienced an average weight loss of one-quarter of their body weight after nearly a year.
Experts have termed retatrutide the most effective anti-obesity treatment, calling it the “Godzilla” of weight loss injections.
Manufactured by American pharmaceutical company Eli Lilly, retatrutide could be approved for use by the NHS within three years, pending further long-term studies.
The trial involved 338 obese adults, with half receiving a weekly dose of retatrutide and the other half receiving a placebo.
After 48 weeks, those on retatrutide lost an average of 24 percent of their body weight, equivalent to more than four stone.
The drug was especially effective in women, who lost 28.5 percent of their body weight compared to 21.2 percent in men. In contrast, the placebo group lost only 2 percent of their body weight.
Retatrutide outperforms the two other weekly weight loss injections currently approved in Britain. The first, semaglutide (marketed as Ozempic or Wegovy), mimics a hormone called GLP-1 that induces a feeling of fullness.
The second, tirzepatide (known as Mounjaro), mimics GLP-1 as well as a second appetite-regulating hormone called GIP.
Retatrutide introduces a third hormone, glucagon, which boosts fat burning and increases calorie expenditure.
Dr. Ania Jastreboff, director of the Yale Obesity Research Center, described the trial results as “striking,” noting that retatrutide achieves a level of weight reduction not previously seen.
Nadia Ahmad from Eli Lilly, overseeing the retatrutide phase 3 trial, expressed enthusiasm about the drug’s performance.
She stated, “We’re very excited about the level of weight loss retatrutide has achieved by activating three receptors, making it different from those currently on the market.”
In comparison, users of Mounjaro experienced a 22.5 percent weight reduction over 72 weeks, while Wegovy led to a 15 percent reduction over 68 weeks. Retatrutide achieved a 24 percent reduction in body weight over a shorter period of 48 weeks.
Professor Alexander Miras, an obesity expert at Ulster University, explained, “Retatrutide is essentially Mounjaro but turbocharged. Glucagon increases energy expenditure—the amount of energy you burn.”
He added, “Previous medications focused solely on reducing food intake, whereas retatrutide addresses both decreasing food intake and increasing energy expenditure.”
Professor Naveed Sattar from Glasgow University, who has worked on other weight loss drug trials, remarked, “Five or ten years ago, we couldn’t have imagined drugs that would induce such significant weight loss.”
He suggested that prolonged use of retatrutide could lead to a 30 percent weight loss, though safety remains a concern and large-scale trials are planned to investigate this.
The study also highlighted additional health benefits of retatrutide, such as improvements in blood pressure and blood sugar levels.
Four in ten participants were able to discontinue medication for high blood pressure. As with other GLP-1 drugs, retatrutide did cause side effects, including nausea, diarrhea, and constipation.
Professor Julio Rosenstock of the University of Texas, who conducted a separate trial of retatrutide in individuals with Type 2 diabetes, commented, “While tirzepatide (Mounjaro) is considered the King Kong of GLP-1s, retatrutide appears to be the Godzilla of weight loss drugs.”
Wegovy is prescribed to tens of thousands of obese patients through the NHS, but due to global shortages, only a small fraction of those eligible have access. Mounjaro is available privately in Britain but is not yet offered by the NHS for obesity.
The cost of retatrutide is currently unknown, but the other weight-loss injections are priced around £200 for a month’s supply.
