Where's some evidence that yohimburn penetrates skin???

I'm using Yohimburn right now, but have not noticed any effects so far...
I tried searching for some research pointing or proving that yohimbine can penetrate skin (to be effective, as makers of Yohimburn claim). I couldn't find any info on that... maybe Yohimburn is just another crap supplement costing tons of $???

THX.

I have the cheaper version of yohmburn...............lipoderm!
It has 25mg of yohmbine per ml
I think its garbage! IMO
But, being I paid for it Im going to make my self use it!
It's probly like most over the counter supplements........10% effective