you can email him and he answers all his emails. I can tell you that it takes way more clomid than nolva to do the same thing, therefore most find it more effective. However, many use nolva in conjunction with clomid during PCT, and where there is no science to back up this synergistic approach, many belive strongly in it. I personally will not do a PCT that does not include both nolva AND clomid. I have seen in my experience that I recover better when using both.