No. After you finish using Ostabulk, you will not need to do a post-cycle therapy (PCT). That’s one of the big differences between Ostabulk and Ostarine. Ostarine suppresses natural testosterone production just like its steroid alternative, Sustanon, does. When you stop taking it your natural ability to produce testosterone will be temporarily crippled, making a PCT necessary to help you get things back on track. While you are using Ostabulk, your ability to produce testosterone is enhanced, not retarded. That makes it possible to stop whenever you want without any negative effects