For those unfamiliar, Muscle atrophy is when we do not regularly use or exercise our muscles, leading to them weakening and deterioating. This is especially prevalent in astronauts as maintaining muscle mass while in space has proven to be an issue, where astronauts typically require physiotherapy when they get back to Earth after their missions in space.
Clearly this is a problem, especially if there are plans for extended space missions, but this is something that NASA is working on. The agency is testing out implants that can deliver medication to the wearer that is designed to help slow down Muscle Deterioation while up in space. This is currently being tested on mice on the International Space Station, which unfortunately means that the medication is years away from being ready and/or approved for human use.