Yeah that's just a brand name for Yohimbine HCL. It's used in topical fat loss products and to tighten skin. People use it a lot on their abs and around the face to tighten things up a bit.
Yohimburn is not exactly a brand name for yohimbine hcl. It is a brand name for a yohimbine based topical.
Yohimburn ES is yohimbine hcl, theophylline, theobromine, Acetyl-l-Carnitine, Acetyl-l-tyrosine and Histidine. So while yohimbine is the basis for enhancing lipolysis in "stubborn" fat deposits (estrogenic fat deposits with high alpha to beta adrenoceptor ratios- hence why its also called female pattern fat) it is not just that.
(not to be nit picking, since you obviously got the gist of it)
note- All transdermal products are called topicals, though not all topicals are transdermals (though many may have "unintended lesser transdermal penetration"--- see below). for instance aspercreme says topical, but its really transdermal. on the other hand most lotions are really just topicals.
see below note- Though in reality anything with isopropyl myristate, various aromatic fractions (l-menthol, limonene, etc) and their parent oils (peppermint, orange, tea tree, most essential oils), propylene glycol, etc.... to some extent will cross the dermal barrier, which is why you should carefully read the labels of things that you apply to your body and hair.
a highly relevant study (not about yohimburn):
**broken link removed**