There is scant evidence for the use of any of the agents sold over the counter as supplements. Of course, many are expensive, so they must be good for something, right? Basically, NO. Since they are sold as food supplements and are not regulated by the FDA, any and all claims can be made, as long as a disclaimer is attached. In short, if the products make you feel good (or better) it is most likely due to the placebo effect, rather than a true effect of the product. (Of course, you have less money in your pocket…)