Fat jab breakthrough as new drug could prevent dangerous muscle loss

READ MORE: How YOU can lose a stone in six weeks... without going hungrySee more Daily Mail on Google - save us as a Preferred SourceBy LUKE CHAFER, HEALTH REPORTER Published: 16:00 BST, 8 June 2026 | Updated: 16:05 BST, 8 June 2026

An innovative drug could slash the risk of muscle loss for patients on weight loss medications, a new study has suggested.The research showed people that taking the medication – apitegromab – while on the jabs lost just as much weight but half as much muscle as those just taking the injections.Previous studies have shown that one third of the weight lost by people using the injections such as Wegovy and Mounjaro comes from muscle and bone, instead of fat.The latest study analysed data from 102 adults taking weekly jab Mounjaro, also known as tirzepatide - studies show patients can lose up to a fifth of their body weight in a little over a year.Half of the group were also given apitegromab, with the other half given a placebo, or dummy drug.People who took apitegromab alongside tirzepatide lost significantly less lean mass compared to those who were taking tirzepatide with a a placebo.This is despite the two groups seeing similar overall weight loss.After six months people taking apitegromab lost around 1.9 kg less lean mass than those receiving the placebo. Mounjaro, Ozempic and other fat-melting injections have ushered in a new era in the war on obesity, but research has shown that they can also cause muscle loss leading to dangerous fracturesThe drug, delivered every four weeks via intravenous drip, is an antibody that stops the activation of myostatin, a protein that regulates muscle mass. When myostatin is activated it can inhibit muscle growth.Researchers, led by experts from AdventHealth Translational Research Institute in the US, found lean mass accounted for 14.6 per cent of total weight loss in the apitegromab group compared with 30.2 per cent among those who took the placebo, according to the phase 2 study, which has been published in the journal Nature Medicine.Commenting on the study, Dr Marie Spreckley, from the University of Cambridge, said: ‘These findings suggest that apitegromab may improve the composition of weight loss by preserving lean mass while maintaining similar overall weight reduction.‘This is an important area of research because substantial weight loss, whether achieved through medication, dietary interventions or bariatric surgery, is often accompanied by some loss of lean mass.‘Strategies that help preserve lean mass while maintaining the benefits of weight reduction are of considerable interest, but whether they improve longer-term health outcomes remains to be established.‘Importantly, although apitegromab preserved lean mass, the study did not demonstrate clear improvements in physical function or cardiometabolic outcomes over the 24-week treatment period.