To build muscle mass and achieve good muscle definition, it is necessary to have good quality protein intake and make it sure that your diet includes all necessary nutrients - "good" fats, "good" complex carbohydrates in proper amounts, vitamins, minerals, microelements, etc.
As to using supplements designed specifically for weight (muscle) gain, consult the lifetips.com's sites:
http://vitamin.lifetips.com/
http://muscle.lifetips.com/
Now one of the top on-line publishers in the world, LifeTips offers tips to millions of monthly visitors. Our mission mission is to make your life smarter, better, faster and wiser. Expert writers earn dough for what they know. And exclusive sponsors in each niche topic help us make-it-all happen.