Interesting question. Test doesn't need to be converted so a larger amount could be delivered (4AD conversion to test is dependant on enzymatic conversion). But then, 4AD is supposedly about 90% as effective as test without undergoing conversion. A transdermal prep should allow easy consistant dosing without the problems associated with shooting suspended test. Assuming 4AD is 90% as effective as test, then it depends on cost (including the slight amount of effort to prepare syno). I don't think either is better than the other for a transdermal.