I'm a big advocate of using various food supplements, especially those that supply nutrients that may be missing in the diet. Other supplements that I think are useful have enough preliminary research behind them to deem them advantageous for health purposes, rather than strictly helping to build muscle or lose bodyfat. On the other hand, bodybuilders and athletes are often the targeted consumers for a host of ineffectual, worthless supplements that do nothing other than enrich the bank accounts of the purveyors behind them. One example of this are the "myostatin blockers" sold a few years ago. These were based on a type of seaweed, and the science behind them consisted of a single in vitro study published in an obscure science journal. In truth, many of the current crop of sports supplements are backed up by little or no evidence whatsoever.
The same group that brought you the useless seaweed-based myostatin blockers now have another supplement. This new supplement is for topical use (sprayed on the skin), and will set you back a cool $125 for an 8 ounce bottle. It allegedly works by inhibiting an enzyme that activates cortisol. Cortisol is associated with muscle catabolism, lower levels of testosterone and growth hormone, and excess bodyfat, particularly in the trunk area. The site selling this stuff offers no evidence of efficacy, but asks consumers to take the word of an established liar. The active ingredient is something called "17-B hydroxyadrenosterone," but don't bother trying to look that up; there is no trace of the term in the existing world medical literature. This suggests either that the company in question formulated from scratch, or that they simply made up the name. The latter is the more likely explanation.
Another company has decided to resurrect the old myostatin blocker. They are selling a product based on follastatin, derived from "avian eggs." Follistatin is a type of protein that does indeed inhibit myostatin. However, the research that showed this effect involved mice that were specifically bred to produce higher than normal levels of follastatin in their bodies. The site selling this stuff lists a single study purporting to show that orally ingested follastatin is capable of being absorbed, and does lower myostatin levels. It isn't disclosed who funded the study, but I'd guess that it was the same outfit selling this stuff. Even worse--the study used to prove this product doesn't exist in the issue of the journal referenced on the site! I guess they thought no one would bother to check. They also don't explain how an orally ingested protein source, in this case follastatin, is able to survive the initial digestive process that occurs with all orally ingested proteins. Indeed, if the stuff is so effective, where is the human evidence? I would expect at least that for a supplement that retails for $99 for a one month supply.
My advice is to stick with proven supplements, or those that have some record of success or evidence of efficacy. This doesn't mean testimonials, since this type of anecdotal evidence is easily purchased. I have no doubt that many will purchase these items, and for them I feel nothing but pity.