Independent & reader-supported — every article medically reviewed

SARMs / Myostatin inhibitors

ACE-031 ACE-031

An engineered protein that was tested in a real clinical trial for a muscle-wasting disease, and it worked in the sense that patients gained noticeable muscle. But the trial was stopped early over safety concerns, including nosebleeds and bleeding gums linked to its effect on blood vessels.

Also known as Ramatercept