Inhibition of the precursor form of myostatin prevents its proteolytic activation and results in reduced suppression of skeletal muscle growth.

Study: Apitegromab for lean mass preservation during tirzepatide-induced weight loss: a randomized, double-blind, placebo-controlled phase 2 trial

This drug stops a protein called myostatin from slowing down muscle growth. People who got the drug kept more muscle while losing weight, compared to those who didn’t — proving it works as intended.

Study: Humans with function-disrupting variants in the myostatin gene (MSTN) have increased skeletal muscle mass and strength, and less adiposity

People born with a broken myostatin gene have more muscle and less fat because myostatin normally stops muscles from growing—so if it's broken, muscles grow bigger.

Study: Myostatin inhibition with orally administered Lactobacillus casei expressing a modified human myostatin protein: functional benefits and translational potential in advanced Duchenne muscular dystrophy

The study used a special bacteria to trick the body into making antibodies that block myostatin, the muscle-growth stop signal. This helped mice move better and showed less muscle damage, meaning blocking myostatin worked — even if muscles didn’t get bigger because the disease was too advanced.

Study: Blocking extracellular activation of myostatin as a strategy for treating muscle wasting

Scientists made a special antibody that stops a protein called myostatin from becoming active. When they gave it to mice, their muscles got bigger and stronger—proving that blocking this protein helps muscles grow.