Whats "an mtf"?
Borax is a naturally occurring mineral commonly mined from dried salt lakes. Of course it can also be used as a cleanser. Table salt is 50 to 100% more toxic than borax, it changes the genetic material and is mutagenic, while borax is harmless in this regard.
Here are very good infos about borax: http://www.health-science-spirit.com/borax.htm
And no, we do NOT want to lower testosterone. We don't want it to turn to DHT, which is our enemy, and for this we can take anti-androgens like Reishi and WP, so that the testosterone can convert to estrogen.
"Veganism is not about giving anything up or losing anything; it is about gaining the peace within yourself that comes from embracing nonviolence and refusing to participate in the exploitation of the vulnerable"
~ Gary L. Francione