Is Myostatin legal in the United States?

The brake on muscle growth. Knock it out in a mouse and you get a mouse twice as muscular, which launched a field. In primates the dominant brake turns out to be a different protein.

Myostatin is made by skeletal muscle and acts back on skeletal muscle to restrain its growth. It is a chalone, a signal whose job is to stop a tissue getting bigger.

Mechanism: Circulates as a latent disulfide-linked dimer held inactive by its own propeptide. Once activated it signals through activin type II receptors, principally ActRIIB, with type I receptors ALK4 and ALK5, through SMAD2 and SMAD3, to suppress muscle protein synthesis and satellite cell activity.

Regulatory history: Myostatin is an endogenous protein, not a drug. Drugs targeting the pathway are investigational; apitegromab has phase 3 data in spinal muscular atrophy.

Approves prescription drugs by indication and polices unapproved products, including peptides sold online. Compounding pharmacies may prepare some compounds under a prescription when the FDA places them on a permitted bulk-substances category.

The classification above is the The Longevity Archive reading of U.S. Food and Drug Administration listings for Myostatin at the reviewed date, not a legal opinion. Rules change, and importing, prescribing and possessing a compound can each be treated differently. Check the regulator directly before acting on anything here.