Safe ways to gain muscle mass include engaging in a structured resistance training program, ensuring adequate caloric intake, and prioritizing protein consumption. Progressive overload through gradually increasing weights or resistance helps stimulate muscle growth effectively. Consuming enough calories and nutrients is vital, as muscle gain requires energy surplus; incorporating a variety of whole foods, especially rich sources of protein, supports this process. Additionally, proper rest and recovery play a critical role, allowing muscles to heal and grow between workouts, which is essential for safe and effective muscle development.