The 3 building block supplements that are needed to gain lean muscles are:
1)Protein (and I don't mean any protein jug off the self). It is a general rule to consume 1.5-2grams of protein per pound of body weight. Diet is one of the hardest things when it comes to gaining muscle/body building etc. It is extremely hard to consume this much on food alone as a typical chicken breat only has 25ish g of protein. You need to supplement your diet w/ shakes or protein bars. What your looking for is "protein Isolate". This type of pretein has upwards of 80-90% of pure usable and absorbable protein. When you get into the "Whey's", your percentage of pure usable protein drops dramatically.
2)Glutamine - Glutamine is an esssential amino acid that helps muscle recovery. Take it a few times a day and especially before bed time. This cuts down on the level of soreness that you will experience the next morning after working out b/c it aids to heal your torn muscles while you sleep. When you work out you tear the muscle...the idea is that you want to eat enough, and comsume enough protein and essential vitamins and minerals that your body rebuils the muscle bigger, thus creating a bigger stronger muscle.
3) creatine - This all depends at what age you want to start taking it. It is an all natural nutrient that forces water into your muscles. The premice behind this is that this water contains the nutrients your muscles need to recover and grow. Red meat is a decent source of creatine however it is not nearly enough.
Lastly, eat 5-7 SMALL meals a day. This will increase your metabolism which will aid in gaining lean muscle weight. Make sure each meal has close to 30g of protein. Your body cannot absorb huge amounts at one time. In other words drinking 4 shakes/150g at one sitting will not do you any good. Once you start going over 30g per sitting your body stops absorbing and you will simply just piss it out.
A combination of a smart healthy diet, these supplements, a very good multi-vitamin and BCA (branch chain amino acid )supplement, working out, atleast 8 hrs of sleep a night will yield you the best results.
one thing to remember is gaining muscle is dependent on these 3 things that I have listed in order of importance.
1)genes
2)diet
3)working out/sleep
hope this helps