What does ACE-031 do? Benefits and evidence

An experimental muscle-growth protein whose Duchenne program stopped over bleeding concerns.

Also called: Ramatercept, ACE031, ActRIIB-IgG1, ActRIIB-Fc.

Myostatin pathway · Soluble activin receptor IIB–IgG1 Fc fusion protein.

ACE-031 traps myostatin and related growth signals. A small trial in women found more lean tissue after one injection. A Duchenne trial stopped after nosebleeds and visible small blood vessels appeared. It has never been approved. In a 2025 laboratory study, none of 14 products sold as ACE-031 contained the trial molecule.

  • In a small study of women past menopause, one shot raised lean mass 3.3% and thigh muscle 5.1% by day 29. (Studied in a trial)
  • People report using it for bodybuilding, but products sold under this name may hold a different protein. (Reported by users)

Uses in the sources

  • Studied for Duchenne muscular dystrophy. The program stopped for safety, and walking benefit was not statistically established. (Studied in a trial) (source)
  • A single dose increased lean mass and thigh muscle volume in healthy postmenopausal women. This did not establish functional benefit. (Studied in a trial) (source)
  • Self-use is reported for bodybuilding, but market products may contain different proteins and have no reliable dose equivalence. (Reported by users) (source)

Related to ACE-031

Sources

Sources checked: 2026-10-18.

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