I've used it and reported the blood work for it. At 100mcg, it is sufficient to start PCT. It has an effect for about 3-7 days depending on how pure your stuff is. Mine wasn't very pure and only worked at kickstarting PCT in the first 3 days. I would just do hcg if you can. 2000iu of hcg in the first week would be more effective and cheaper, imo.