Reports in the popular press suggest that taking creatine supplements may result in higher energy levels. But performance data is mixed, with nearly as many studies showing positive results as negative ones. And since creatine is excreted by the kidneys, there are concerns about possible long-term effects on that organ. Unless you're a strict vegetarian, you don't need to increase protein consumption to boost athletic performance. Yet research studies have not demonstrated benefits to most athletes.
Amino acids are ineffective and their long-term health effects are unknown.
Some benefit of CoQ10 supplementation has been seen in patients with heart disease, including improvement in exercise capacity, but ergogenic improvements are generally not seen in healthy subjects. Don't waste your money. Caffeine Affordable and readily available in coffee or tea, caffeine seems to be among the few ergogenic aids that have been shown to work in a number of scientific studies. The caffeine equivalent of 2 cups of coffee ingested before exercise increases endurance in both well-trained and weekend athletes. The theory is that caffeine stimulates the breakdown of fats for energy which slows the depletion of glycogen, the main energy stores of the body.