Whether or not MK 677 causes anxiety is currently up for debate, however the majority of experts (including myself) agree that pharmacologically it should NOT cause anxiety, ss sarm source rad140. There are not any studies (as of August 2020) that list anxiety as a side effect, and reports of it on the internet are few and far between. It is much more likely that anxiety experienced on cycle is entirely situational. In my own personal experience, my anxiety goes down while taking MK 677. The improvement in sleep quality and appetite seem to directly impact my mental health in a positive way.Ibutamoren may do so indirectly, through the stimulation of the ghrelin receptor, which amplifies REM sleep duration and insulin-like growth factor (IGF-1), ss sarm source rad140.