There are three common flaws/fallacies in the claims accompanying many performance enhancing products including:
As a result, a product may be promoted as having a helpful or beneficial effect when none is present - a placebo effect. The placebo (definition: an inert compound, identical in appearance with the material being tested in experimental research, where the subject and the experimenter may or may not know which is which) effect results from our optimism and hope that a medication, supplement, or training program will be beneficial, biasing us toward a positive impression of the results. This is best demonstrated when a sugar pill (the placebo) is used in studying disease treatments. When told that the placebo will help, a large percentage of subjects report significant benefits. However this beneficial effect usually lasts for only a few doses and then wears off. This study nicely demonstrates the placebo effect. A 1% improvement based on mind set or mental expectations alone.
We can avoid confusing a placebo effect with a real, reproducible benefit of a supplement by comparing two groups of athletes in carefully monitored or "controlled" studies - one group using the active ingredient being investigated and another group given an inactive or sham agent - and not telling either group ("double blinded") whether they had the placebo. Only if we as individuals are "blinded" i.e. not told whether we are using the active agent, and then rigorously compare our own results with both a supposedly active and inert agent will we be able to eliminate a placebo bias.
The placebo effect is almost always a positive one. This explains why an athlete, using a product without bothering with an inert comparison and then giving a testimonial based on his/her own perception of its benefit, will almost always report the results in a positive way.
A third error results from a misunderstanding of the possibility of random positive results when studying supplements, even when they may be no real physiologic benefit. Clinical studies use statistical methods to try to minimize the potential to interpret random success from a reproducible effect (positive or negative) of a supplement. But even in the best of studies the potential remains for random, non-reproducable results. So if you find several studies, with only one supporting a positive or beneficial effect, be skeptical that the single positive result may have been by chance alone (and thus not reproducible). Similarly, be wary of the single, often quoted study with results no one else can duplicate.
If you have found a product you feel is proven, you next need to decide how to use it to improve your cycling program. Two issues to consider are:
Dosing. It has been known for centuries that a large enough dose of a useful medication or chemical agent can be harmful or even fatal. The renaissance apothecary Paracelsus warned his contemporaries that "The poison is in the dose." which was intended to warn them that there is a fatal or harmful dose of almost any active chemical compound. An example is water. If you don't drink enough, you get dehydrated and will do poorly on a ride - so there is some amount that will be helpful to improving your performance. But if you overdo and drink excessively, you can develop hyponatremia, become ill, and at its extreme face the possibility of severe complications and even death. So the old adage that "if a little is good, a lot is better" does not hold true when using additives and supplements, and there is some personal risk in pushing doses that are higher than those recommended from prior studies.
Appropriateness. Try to put the claims (proven of course) in perspective. An improvement of a few percent obtained in repetitive sprints to exhaustion on a bike trainer may have little relevance for an endurance event or for the recreational cyclist.
The message is to be skeptical about unbelievable claims for performance enhancing products. Unless they are proven in well designed, blinded studies, assume that a claim which sounds too good to be true, probably is. There are no shortcuts for a well designed training program supported with sound nutrition. And although there may be little risk in trying supplements (at their recommended dose), there is a monetary cost for those with a limited budget for their athletic pursuits and the potential to lose focus on the key to success - a good training program.
Here is a story from an associate in a web coaching e-mail group, Graham Fowler, that helps to illustrate the point.
"During a lull in cycling I was involved in marathon canoeing as an instructor and competitor. It was during a 24 hour "orienteering" marathon that at approx 3 AM one of our mixed team of 5 became so sleepy and lethargic he insisted that he could not carry on. I had some salt tablets with me to stave off cramps etc. While resting on the water I told some story about these tablets being so strong that you wouldn't sleep for days if you took one. I broke one in half and in to quarters and gave him one, with a drink of water. I suggested that within 15 minutes he would be wide awake and completely rejuvenated. To my amazement his strength returned on cue and paddled as if he had just started. This man is now the president of the Skeptics Society of South Australia. I have never told him that they were salt tablets.
Powerful stuff is belief.