I can only tell you from personal experience, that a certain amount of everything enters the bloodstream intact (unless specifically designed to break down) and depending on your sensitivity (I am particularly sensitive) it will cause side effects. People with strong androgenicity in their body might be able to use a dose that helps their hair without affecting them systemically, but people who have high aromatase and E receptor expression throughout the entire body like myself are screwed.
It takes large doses of, for instance, equol, a plant phytoestrogen, to do anything for hair loss. Brotzu put a daily amount of ~0.3 mg of S-Equol in his lotion, it did nothing. We had a small trial here on the forum about 3 years ago taking racemic equol, huge amounts, I personally used around 60 mg daily, so even if the binding affinities are 2 orders of magnitude smaller than estradiol, that equates to around 0.6 mg of E2, 6 times higher than the normal daily dose of transdermal E2 for HRT. Of course, these phytoestrogens will not express the receptor to the same extent as E2 even once they do bind. But the dose was still high enough for significant sides. I personally got gyno symptoms and a couple of guys also messaged with the same, along with feeling fat accumulation in hips and buttocks.
Hence, I am not looking forward to things like this because it boils down to having to use a high enough dose to combat hair loss which invariably leads to side effects.
As far as MEP. The concept sounds as good as Fluridil, theoretically. Breaking down into inactive metabolites. If this is really true, then we should be able to use a high dose to compensate for the relative lack of binding affinity and receptor activation. The main obstacle I see at this point is the availability and pricing. There seems to be only one cream where the active ingredient's concentration isn't disclosed, and it's very expensive.
