possibly, but it will ALL be lost (possibly even lose more than gained) if they do not eat right, rest properly and train hard after the cycle...
if someone is a hardgainer they just have to eat more... i know it sucks because you probably already eat a decent ammount, but some of us just have to stuff our faces with protein and carbs all day long to see gains...
i have to eat a shitload of calories to make gains, so i started doing powerlifting as a lightweight... heavier lifting also builds very dense, KEEPABLE muscle...