The recipe for building muscle is quite simple; quality nutrition, muscle resistance training and recovery.  

Training with weights slightly damages the muscle fibre and as the body repairs the muscle it makes the muscle stronger, and stronger muscles are bigger muscles. It has been suggested that sticking to simple compound exercises (ones that work many muscle groups at once) like squats, bench presses and deadlifts, is the best way to kick start muscle growth. 

Nutritionally protein plays a big part in muscle growth and having a protein supplement can assist in providing the extra nutrition growing muscles need. In addition, if you’re slight or a ‘hard-gainer’ then extra carbohydrates can also assist in the body to build muscle. 

Also please note that recovery is just as important in growing muscles. Muscle don’t grow in the gym, they grow when you’re recovering so it’s essential to also get plenty of rest and recovery, and to keep feeding the muscles with a high quality, high protein diet and nutrients that support muscle development.