Also, aye, I realize that eight days isn't much to go by, but the effect of YK-11 that I was most intrigued by was not the SARM aspect, but that it is simultaneously a myostatin inhibitor. Myostatin inhibition isn't something that "builds up", so the effects should be pretty much immediate (but not necessarily immediately noticeable)
I have yet to turn into the muscle cow that is sometimes shown during discussions of myostatin inhibition. I will say that my appetite is increased and, despite eating LOADS of carbs and fats throughout the day (Estimated about 300-400g of protein a day, about 200g-225g of complex carbs - excluding fiber and sugars, and about 125g-175g fat) I have been losing body fat.
Of course, I am also occasionally taking Clenbuterol (not very often, and at 100mcg / dose, because that stuff is TERRIFYING), but, even with that, I'm not running a deficit by any means and have been putting on muscle very steadily. Even moreso than when I was running DMZ 3.0 + 4.0. In the last week, I have woken up three times so hungry that I have made a 3 A.M. protein shake just so I could get back to sleep... And I always have a casein shake with about 50g protein and a tablespoon of waxy maize about two hours before bed.