Par Deus, who knows more about transdermals than most of us know about our houses, said that by using DMSO in conjunction with his transdermal formula, you could expect real world delivery of 40%. I went on to speculate that if you did everything else that I advised, including rotating the site of application and the application of DMSO after the transdermal had dried, that 50% was possible. Patrick Arnold, for his part, thinks the lot of it is nonsense, and that 10% is more realistic. I think this is flat wrong, given that Androgel gets 10%, and it is designed basically without efficiency in mind whatsoever -- the cost of the testosterone in the patch isn't a limiting factor, issues like ease of use, skin irritability, etc. are far more in play.