I really can't comprehend any suggestion that GH doesn't have a distinct and dramatic positive effect on lean mess, reduced fat mess and athletic performance. This is well established in recent scientific literature - for instance here is a review -
https://www.ncbi.nlm.nih.gov/pubmed/28514721
The usage of of MK-677 as a replacement for using exogenous GH for wasting syndrom and enhanced performance is still in its infancy, what I find interesting both in the article which is cited in this thread as well in other articles, and also supported by empirical data others and me gather on forums is that the MK doesn't have positive impact on reduction of fat mess in oppose to exogenous GH which has a proven effect in this area
https://www.ncbi.nlm.nih.gov/pubmed/28514721
It is interesting to note that Anamorelin, a GH secretagogue with close similarities to Ibutamoren (MK-677) and the same mechanism of action, was recently released as a script drug for lean mas retention in Europe.
This, along with all the research previously done on M-677 (demonstrating its lean mass-building properties) is pretty strong scientific evidence for its effectiveness as a performance enhancer. Of course, the anecdotal evidence is overwhelming.
While clinical trials do appear to support the belief that exo. GH is superior from a fat loss standpoint when compared to MK-677 (on an iu to iu basis), I do NOT think this means that MK-677 does not stimulate fat loss. Why? A few reasons. One, I think it is important to note that MK-677 has very strong appetite stimulating effects in the majority, while exo. GH does not. This should not be discounted, especially considering the study parameters. You see, in all the studies ever conducted on MK-677, none were ever done with the express intention of determining its true fat loss capabilities. Basically, test subjects were instructed to take MK-677 at a set dosage and required to report back for testing at predetermined times. No dietary restrictions were put in place, which is almost guaranteed to drastically skew the data from a fat loss standpoint.
How could it not? Giving people a drug which dramatically increases appetite is extremely likely to lead to increased caloric intakes across the board. When other drugs, which promote a similar degree of appetite stimulation, have been studied for their effects in test subjects, fat gain is always a common denominator. In fact, I think one would be hard-pressed to find a single study in which similarly potent appetite stimulating drugs, when diet is not controlled, did not result in fat gain...and many such drugs exist spanning multiple classes of drugs.
Given MK-677's ability to potently stimulate appetite, one would expect test subjects to gain fat, not maintain bodyfat levels. Yet, that's exactly what happened. Furthermore, the research shows that MK-677 increased metabolism (similar to GH), which in itself should have resulted in fat loss. The fact that it did not indicates that subjects were simply eating more than usual, thereby preventing its fat loss/metabolism stimulating effects from resulting in measurable fat loss.
It is also relevant to note that we currently have no explanation for MK's inability to induce fat loss in test subjects, aside from the explanation presented here. This actually makes the most sense, as GH is universally acknowledged to stimulate fat loss; a hormone which MK-677 does a great job at elevating.
Lastly, there is also anecdotal evidence to suggest it does stimulate fat loss. Not only have people in this thread claimed to have experienced fat loss with MK-677, but so have many others in various forums across the Net.
Of course, MK-677's fat loss effects haven't been clinically proven, but when looking at the evidence as a whole, the above explanation at least seems plausible. This is not to say that it's fat loss effects are equal to GH, but I severely doubt that has no effect in this area. From what I can see, the available evidence appears to contradict that train of thought.