Free test is what helps build muscle, but with products that raise total test, you also raise Total DHT and Estrogen unless you take something to mitigate the additional rise in each. DHT can be controlled with simple Saw Palmetto. That will help with prostate and hair falling out.
Too much of any Anti-Estrogen could lead to a loss of libido. Anything that reduces estrogen levels also has the possibility of eliminating it. Like I said, I found out that your brain requires a small amount of estrogen in order to stimulate arousal. You have to find the levels and dosing that works for you. I was taking 500mg of chrysin first am, after lunch, and right before bed and I noticed the effects inside of 24 hours. Probably if I reduced it to either Just before bed or bedtime and first am, I would not have impacted my libido. I think before bedtime is the most important time to take anti-E supps, as that's the time when your test levels are the highest, maybe second only to pwo.
And I was joking about estrogen being a "chick hormone."
I would pm Patrick Arnold and ask him about libido loss with 6-Oxo, that is his product btw. I think that is going to be a tolerance level thing and something that would have to be determined on an individual basis. Personally, that's why I like buying in bulk and capping/formulating my own stuff, because I get what I want and in the doses that I think work for me.