The $570 million weight on NHS shoulders

The NHS has seen prescriptions for tirzepatide-type injections skyrocket, with English doctors writing 3.1 million scripts in the 2025/26 financial year, driving NHS expenditure above £570 million.

This is a staggering figure, eclipsing any other single medication in the past two decades. While the weight-loss benefits of tirzepatide, Ozempic, and similar agents are undeniable,earlier research has flagged a troubling side-effect: a substantial proportion of the weight lost is not fat but muscle and skeletal tissue,raising the risk of fractures and functional decline.

Preserving muscle, not just weight

A new Phase-2 trial suggests that adding the experimental antibody apitegromab to tirzepatide therapy can dramatically cut the loss of lean tissue that often accompanies the powerful weight-loss injections .

The study examined 102 adults who were receiving weekly tirzepatide and randomized half of them to receive apitegromab, an intravenous drug administered every four weeks that blocks myostatin activation, while the other half received a placebo.

Over a six-month period, both groups lost a comparable amount of total body weight - roughly one-fifth of their baseline weight - but the apitegromab cohort preserved far more muscle and bone mass.

From catabolic effect to mechanistic approach

By targeting myostatin, a protein that normally restrains muscle growth, apitegromab offers a mechanistic approach to preserving muscle while still allowing patients to reap the metabolic advantages of the injectable therapy.

Commentary from experts underscores both optimism and caution. Dr Marie Spreckley of the University of Cambridge highlighted that preserving lean mass while achieving similar overall weight loss could improve the quality of weight-loss outcomes, especially for patients in whom muscle loss would be detrimental.

What auditors flagged in the May filing

The NHS has seen prescriptions for tirzepatide-type injections skyrocket, with English doctors writing 3.1 million scripts in the 2025/26 financial year,driving NHS expenditure above £570 million.

This is a staggering figure, eclipsing any other single medication in the past two decades. While the weight-loss benefits of tirzepatide, Ozempic, and similar agents are undeniable, earlier research has flagged a troubling side-effect: a substantial proportion of the weight lost is not fat but muscle and skeletal tissue, raising the risk of fractures and functional decline.