Whey is by far the most popular protein supplement. It is one of the best. Whey is superior to other proteins such as casein, soy and wheat for increasing protein synthesis. This is most likely due to the very high leucine content of whey, compared to other protein sources. Leucine is the amino acid responsible for increasing protein synthesis. Research has demonstrated that the ability of a protein source to increase muscle anabolism is proportional to the leucine content of the protein source. Furthermore, whey has been shown to increase lean mass, even when compared to the same amount of casein. Research also suggests that whey helps recovery from exercise by reducing muscle damage from training. Whey is affordable and tastes great too. Consuming 25-40 grams whenever you need a high-quality protein source should be an effective dose.