I'm with the other guys. It comes down to your diet and your training.
However, should you wish to take supplements, Whey Protein is pretty much the most important supplement as it aids with muscle repair and recovery.
Depending on your goals, there are different types of protein powders available.
James has posted a very detailed guide to Whey Protein above.
When you are ready to get some Whey Protein, remember, like with most things, you get what you pay for!
In my opinion, one of my favourite Whey Protein's has to be: Avenches Biotech - Pure Whey.
It's low carb, low calorie and mixes exceedingly well. It also has a great taste (which is always a bonus).
It is a blend with Whey Protein Isolate and Hydrolysate which simply means, faster absorbing.
It's not the cheapest, but in my opinion, it competes with Optimum Nutrition 100% Whey in quality and beats it in price. Well worth the money!
Hope that helps!
post edited by James - 2014/12/17 17:29:03