Alright... after I did a bunch of googling, here's what I found out about zinc
"A natural substance known to control DHT is zinc. However, zinc is also an aromatase inhibitor which indirectly increases testosterone. This can decrease the anti-dht effects. In fact, zinc is even recommended for low testosterone levels."
Aromatase is what converts testosterone to estrogen. So I suppose if you have excess estrogen, zinc would be wonderful. If you have low estrogen and high testosterone levels and take a higher dose of zinc, then maybe it could have adverse effects? Hmm..