Listed to the latest Paleo Solution podcast (gotta do something with no BioJacked radio).  And Robb Wolf seems to feel there really aren't any studies that show one interferes with the other at all.  I guess this kinda jives with what Keifer wrote in the Caffeine and Creatine article.  "the best answer I can offer is a firm “we’re not sure.” I haven’t been able to find any studies on that—and believe me, I’ve tried—so this is still an open question."Here's my attempt to transcribe Robb Wolf for those that don't feel like listening to the podcast:Robb:  So the short answer here is Caffeine really doesn’t seem to have any effect in changing the kinetics of Creatine supplementation/absorption.  Vanakoski did a study on this that was pretty solid.  There’s also this paper in Pharmacological reviews, Clinical Pharmacology of the Dietary Supplement Creatine Monohydrate and this thing is a monster, it’s like 6000 pages long.  They end up looking at the transport kinetics and compare and contrast it with and without caffeine and there is just no difference.  So I’m not sure where…Oh I do remember there was an early study that seemed to indicate caffeine interfered with creatine absorption and subsequent studies seemed to prove that wrong.  So the first study has been invalidated, but the first studies information has rooted into the psyche of creatine manufacturers and users. http://robbwolf.com/2013/03/19/trace-food-contamination-episode-175/[31:16] Creatine With Caffeine