Estrogen conversion is largely a function of the androgen in question, and enzymes conversion rates. Individual differences are present, but in my experience and in every bit of feedback I've seen on finished products/homebrews (including my own bloodwork) - there's little issue in the case of TOPICAL DHEA. Orally, it's a WHOLE 'nother story.
In any case, getting enough of it into circulation is job #1. In this respect, you'll see the term "flux" showing up over, in the trandermal literature. This simply refers to the amount of surface area the product is spread across/over. Yes, some areas of the body have thinner/thicker skin covering such, but PE's (penetration enhancers) should be included to address. The gold standard is DMSO, but prude that the FDA is - they take a dim view of such. You might spill an oz. or two by accident, into your topical. It's unfortunate but happens. The world is frought with hazard, given all the multi-tasking that goes on today.
ONE CAVEAT: DMSO (with the exception of the incredibly rare "odorless" variety PA once sold), stinks to high heaven. Accordingly, I spill at least 2-3 oz. of D-Limonene (constituent of orange/citrus peel) into the diabolical mix. It's an excellent PE enhancer, and has a pleasant citrus likesmell.
Mistakes happen, so be on the lookout for them. Hope that helps...
