i tried GW for 4 weeks then i tried S4. when i start using GW ..i can see the changes..i was informed s4 side effects..so next 5th week i handle s4 with care. keep monitor my workout..its fine ..im now in 2nd week using s4. past few days, when woke up at morning.i can see black/yellow box in eye sigh.. its temporary..when i open light its gone. i use s4 for 5 days per week.. sarms is not safe. if u decide to use it..be careful.. dont go too much