I have been an avid backpacker and trail runner for most of my adult life. I don't know if it ever bumped up my testosterone levels, but mentally its great. However, I always drop weight on backpacking trips. Usually close to a pound a day. For example, this last summer I did a solo week off trail in the Wind River Range in the Bridger Wilderness. I dropped 5 pounds. Carrying yourself over high passes, across boulder fields, glaciers, and so on is very strenuous and you are only eating what you are carrying with you.
It has to be good for us though because its what we are evolved to do.
My campsite at Peak Lake: