But how many of those supplements actually help you build muscle? Just because some of them helped a diabetic lab mouse put on muscle over a two-week period doesn't mean you'll experience the same effect. Animal research is a good way to set the stage for future human studies, but it's no substitute.

What you eat, how you exercise, the amount of sleep you get, and what you supplement all play a role in building muscle. Just keep in mind, supplements are nowhere near as important as diet, exercise, and sleep. Those three are your foundation. Without supplements, you'll still build plenty of muscle, assuming your exercise routine is consistent, your diet is healthy and contains enough protein, and you get enough quality sleep. Supplements are just the icing on the cake. They'll help you push yourself a little harder.

So which supplements actually work?