Often, people ask me my opinion of supplements. I always tell them that 95% of the stuff that is sold as a "healthly supplement" is a waste of their money. You can get so much more value and performance if you just spend your money on quality, whole foods and time following a sound strength training program. One supplement to your diet and training that is overlooked, but is extremely vital, is sleep. More specifically, nine hours of quality sleep every day. That is 63 hours of sleep per week.
No supplement has a more vast and profound impact on your physiology than sleep. Put another way, lack of sleep can have such a deleterious effect on everything from metabolism, to obesity, to muscle recovery to cardiovascular disease risk. Even if the sleep comes in a short, mid-day nap, its effects are significant.
So bypass GNC and the rack of supplements at you local gym. Accumulate 63 hours of sleep over the next week and watch your mood, focus, motivation, strength, performance, and body improve to a new level. Oh, and it is free!