Does low level or high level of testosterone causes hair loss?

I've taken a blood test for hair not long ago. I have a low testosterone level and a bit low Zinc. I was wondering if the low testosterone could be a reason for thinning hair at the crown of my head. I got my hair cut very short and it seems to grow very well. But I've noticed some thinning at the back. I've always heard that high testosterone causes quick baldness. So I'm very lost in this sense, since I don't know which level is worse. What are the legitimate ways to figure out how to control testosterone. I exercise everyday, not so active sexually. Could this be the cause? and should I exercise regulary or that's what's keeping my testosterone low. I'm 24 y.o. male.