First off I'd like to say that I work for a company that manufactures a nutraceutical formulation containing S-equol. The company is called Eclipse Nutraceuticals and the product is called Folexen. For those who are interested I will outline details of the product, the science behind S-equol, as well as itís relevance for the treatment of androgenic alopecia.
The currently accepted wisdom is that the cause of MPB is a genetic trait in some men that causes scalp follicles to miniaturise when exposed to the hormone DHT (dihydrotestosterone). DHT is produced when an enzyme called 5AR (5-alpha-reductase) acts upon testosterone and adds an electron to it. This chemical change results in DHT having different physiological effects upon the human body when compared to its parent testosterone.
If I could speculate, Iíd say that the root cause of MPB was a genetic expression that causes some of us to have 5AR active INSIDE our follicles, but dependant on location. Thatíd also explain why MPB happens in a certain pattern and not in a universal loss of hair. There is some indirect supportive evidence for this theory. 
Serum DHT is not the issue since it is bound to ABP (Androgen-Binding Protein) and becomes less lipophilic and hence less able to cross the cell membrane into the follicle.
Dutasteride and Finasteride work by inhibiting the action of 5AR so that its ability to convert T to DHT is hampered. These compounds work through a process of irreversible inhibition of the enzyme - they have the ability to modify the active region on the surface of 5AR, so the testosterone cannot use the enzyme. Thus the conversion becomes energetically unfavourable and less likely to occur. To be more precise, there are two types of 5AR. Finasteride targets type 2 while Dutasteride can inhibit type 1 in addition to type 2.
For some men this will be enough to halt hair loss or even regrow hair over time. There are some side effects to inhibiting 5AR because the testosterone that isnít being converted to DHT can trigger other hormonal responses in the body, as part of the natural hormonal feedback loop that we all have. Some men report lack of libido, erectile dysfunction or other side effects due to the increase in female hormones that are produced to counteract the higher levels of testosterone.
Enzymatic inhibitors have a drawback in that, for some men, the recommended dosage might not be sufficient to deactivate all the 5AR without causing other problems. In other words everyone probably has a dosage level at which the medication will work, but for some people there are too many concomitant side effects for the treatment to be safe. Merck have shown that normal dose Propecia resulted in improvement for 77% of patients . Presumably a different treatment is required for the remaining men.
This is where S-equol can step up to the plate. It has a mode of action that is very different to the 5AR inhibitors. Instead of preventing the production of DHT, it binds strongly to the DHT molecules. When DHT has S-equol attached to it, it is no longer a form of 'free DHT', i.e. it cannot cause MPB because the molecule is no longer able to bind to receptor sites.
The ability of S-equol to bind to DHT is very strong , which is good news for us. Theoretically there are sufficient levels of S-equol in serum, all the DHT can be mopped-up before it can cause damage, even the DHT that is inside hair follicles. S-equol is a small molecule, not a protein, so it has no problem crossing cell membranes.
S-equol is formed in some individuals after consuming soy products. Scientists have been able to prove that various bacteria have the ability to transform a soy isoflavone (daidzein) into S-equol. It is theorised that people who are able to produce S-equol have an intestinal environment that supports the species of bacteria that allow this transformation to take place.
If 5AR blockers are working for you then I am not going to recommend cessation of treatment. But anyone who is still looking for a solution might want to consider this product (visit http://folexen.com).
Please let me know if you have any questions and I'll do my best to answer them for you!