Testosterone, that much-talked about hormone largely responsible for those qualities deemed to be masculine - deep voice, body hair, virility, dominance, and physical strength.
Young men want to increase their already high T-levels, while older men want to prevent their T-levels from decreasing.
But, isn't it inevitable that testosterone levels decline with age, regardless of preventative measures?
In a word: no.
At least that is what David Handelsman, a leading hormonal researcher, says: