Gaining 1 kg (2.2 pounds) of pure muscle in a week is highly unlikely. Muscle growth is a gradual process that requires consistent resistance training, proper nutrition, and adequate rest. On average, beginners may gain 0.25 to 0.5 kg (0.5 to 1 lb) of muscle per month, while more experienced bodybuilders may gain even less than this. Aiming for sustainable progress is the key to long-term success.