I'm 21 and about 61kg. My main goal is to add lean muscle and get bigger, but not too big. Weight Gainer sounds great, but does it really work? And is there anything else that you would recommend to help me achieve my goals?

"Do they work?" Depends on what your expectations are and what you want it to do. The Weight Gainer is a source of protein, calories, colostrum and L-glutamine which can supply the nutrients the body needs to repair, maintain and grow. It takes hard, intense and heavy training 2 -3 times per week to stimulate the muscles to grow, combined with a nutritional intake that supplies all the nutrients and calories needed for repair and growth and enough quality rest/sleep for this to happen. No supplement replaces these factors. Make sure you are getting these factors correct and, yes, Weight Gainer will help.