After reading those FDA letters all I can do is wonder about the imagination of the marketing departments of those companies.
I will confess, though, that I'm taking soy isoflavones in the form of tablets marketed for menopausal women. It's something of a test, really, and not the main thing I'm using.
For some background, a couple of years ago I started with finasteride, initially for hair loss. Pretty soon I was happy to notice that I also got some of the listed 'side' effects, such as a little breast growth (to the extent that nowadays it generally feels better to wear a 36A bra than not) and a notable reduction of unwanted erections. Yay! I've since had my physician change the prescription to dutasteride, and for the most part am happy with the results.
At the moment I'm conducting a small and not all that rigorously designed test series of supplementing the DHT blockers with soy isoflavones (just the dosage suggested on the box, which isn't near the amounts mentioned in previous posts). I just resumed the pills after a break of about two weeks, and it does seem that with those I'm less irritable, sleep better and have a little more interest in sex. That's about as far as it goes, though, and a part of it may be because of the vitamins in those pills instead of the isoflavones. Still, it does point in the direction that my head might work better with the addition of oestrogen or its relatives, so perhaps it's getting time to see someone about the real thing...
Nfr
