Protein powders are exactly as the name implies convenient powder forms of protein which aid active individuals in reaching their target protein levels for muscle growth without too much trouble and usually in a great tasting way too!
The most popular and widely used protein powder is whey protein, generally it is recognised to have the best amino profile for muscle growth. The cost of whey protein powder has been increasing over the years and there are times when a slower digesting protein powderor time release protien powder is preferred. This has led to a rise in popularity of casein protein powder (also derived from milk, but much slower digesting) and soy protein powder (derived from soy beans) as well as blended protein powders involving whey protein, soy protein and casein protein powder, these sometimes represent the cheapest protein powder, but not neccersarily bad quality offering a wider range of amino profiles.
For people who have lactose intolerance issues options such as whey isolate and soy protein powder offer excellent alternatives as does egg white protein powder due to the lack of lactose in them.
An excellent quality protein powder blend is Boditronics Just Protein