I've used S4 successfully at the end of a cycle and before post cycle therapy (pct). It worked well to not only maintain, but actually gain strength. I have some guys on the PP forum who are using the Ostarine right now and logging it on a thread I started there. They are using it with positive effects so far, about 2 weeks into it right now. In the future I plan to use it as well. Ostarine has had some pharmaceutical companies doing research with it and these inactive patients actually gained about a pound of muscle with only 1-3mg/day. Not bad for sedentary people with such a low dose. No side effects were evident.