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I'd have to say Nolvadex. Both as an on-cycle anti-estrogen and a post-cycle therapy. As an anti-estrogen its simply much stronger, demonstrated by the fact that better results are obtained with 20-40 mg than with 100-150 mg of Clomid. For post-cycle, this plays a key role as well. It deactivates rebound estrogen much faster and more effective. But most importantly, Nolvadex has a direct influence on bringing back natural testosterone, where as Clomid may actually have a slight negative influence. I promote the use of Nolvadex over Clomid post-cycle (as if being 3-4 times stronger and having more of a direct effect on restoring natural test wasn't enough is because it;s a lot safer. Not just because it improves lipid profiles, but also because it simply doesn't have the intrinsic side-effects that Clomid has. Clomid causes more acne for sure, but thats mainly because you need to use a 3-4 times higher dose.