What are myostatin inhibitors?
Myostatin inhibitors are drugs that block the activity of myostatin. Myostatin is a protein in the body that limits the growth and development of muscle. There is research on using these drugs for muscle-wasting conditions such as muscular dystrophy and sarcopenia. They are also being studied for cancer-related muscle loss and, along with GLP-1 drugs, for weight loss without loss of muscle mass. They are usually given by intravenous infusion or subcutaneous injection. Examples of myostatin inhibitors include ACE-O31, bimagrumab, domagrozumab, landogrozumab, stamulummab, and trevogrumab.
There are naturally occurring myostatin inhibitors such as follistatin (FST) that are available online; however, they can have other biological effects that make their safety and efficacy uncertain. There are no FDA-approved pharmaceutical formulations of follistatin.
How do myostatin inhibitors work?
By inhibiting myostatin’s activity, myostatin inhibitors increase muscle mass and strength. Many are monoclonal antibodies that bind and neutralize myostatin. Others act as a decoy receptors that trap myostatin, which prevents it from binding with its natural muscle receptors.
Are myostatin inhibitors safe?
It’s too soon to tell. Clinical trials evaluating the safety and efficacy of these drugs are underway. They are not yet FDA-approved. They are banned by the World Anti-Doping Agency.
Do myostatin inhibitor supplements actually work?
It is unclear whether myostatin inhibitor supplements work. There are animal studies that show efficacy. However, some clinical trials did not show benefits or were stopped early for safety reasons.
Side effects of myostatin inhibitors
Based on their mechanism of action, it is possible these drugs will weaken tendons and reduce bone density. Muscle spasms can occur. Some of these drugs cause bleeding disorders (nosebleeds and bleeding gums) and vascular damage. The thickness of the heart’s wall might increase due to an increase in the mass of cardiac muscles. There is a risk that increasing muscle mass can lead to fibrosis and blood supply issues that will affect muscle function.
Do myostatin inhibitors interact with other medications or supplements?
There is very limited information available on interactions, as myostatin inhibitors are still in clinical trials.
Some supplements, such as dark chocolate, that contain epicatechin naturally inhibit myostatin. Green tea, black tea, vitamin D, and high-dose creatine also inhibit myostatin. A potentially positive interaction being investigated is whether the combination of a myostatin inhibitor and a GLP-1 agonist might result in reduced body fat while preserving muscle mass.
What should you do if you have a bad reaction to a myostatin inhibitor supplement?
If you are a participant in a clinical trial of a myostatin inhibitor and you are having a bad reaction, contact the clinical trial coordinator. If the adverse reaction is due to a myostatin inhibitor you purchased online, seek medical advice from a health care professional.