Registrant G has phenibut also, so I use it sparingly. Sometimes I use 1/3 off a scoop. It gives me deep, very restful sleep and reduces the number of times I wake up to maybe 1x per night. I can sleep for 10 hours easily when I use it, but after 7-8 hours, I can wake up. At a full scoop I wake up dizzy for a while. My mood improves and I am calm for all of the next day and usually the day after that to a lesser degree.
Can't say I've noticed any physique improvements, but again. I use is just 1-3 times per week.