Can myostatin inhibitors preserve muscle during GLP-1 weight loss?

There is a credible clinical signal, but it depends on the exact drug and outcome. In the phase 2 COURAGE trial, the sponsor reported that adding trevogrumab to semaglutide prevented about half of the lean-mass loss observed with semaglutide alone over 26 weeks. Trevogrumab is an antibody against myostatin. Taldefgrobep alfa acts on myostatin and activin signaling through a different protein approach, and its obesity trial is testing a separate hypothesis. Their results should not be treated as interchangeable.[1][2][3][4][5]

The crucial distinction is between preserving DXA lean mass and preserving useful muscle function. Lean mass includes water and other non-fat tissues; a change does not automatically mean better strength, mobility or training performance. Taldefgrobep’s spinal muscular atrophy trial missed its main motor-function endpoint despite favorable body-composition signals. Future obesity reports need functional outcomes, adverse events and durability alongside body-composition measurements. Neither program validates untested products marketed as follistatin or generic myostatin blockers.[1][2][3][4][5]