Hi..

Pre workout supplements are meant to be taken 20- 30 min prior to workout which helps in boosting your energy level, enhances endurance, increases blood circulation, pumps up your muscles and helps you work out for long hours at the gym.Where as glutamine is a taken either post workout mixed with the protein supplement or 30 min before bedtime at night to speed up the muscle recovery. It directly acts on your skeletal muscle which helps in providing good muscle recovery.