Get more from top Personal Trainer Russ Howe PTI: Which supplements should you use to build muscle quickly? Leading fitness instructor and personal trainer Russ Howe PTI shows you the top 6 supplements his clients use to pack on size very fast. br br This list has become a firm favorite among Russ' many clients, who range from busy mums and dads to models and actors. br br More supplements tips from Russ on his website.