The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".   Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.  The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.  Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.     
Testosterone or "T" as it's known has always been and is today the most successful muscle building hormone in existance. It's literally the hormone that separates the men from the boys. So what about testosterone supplements & testosterone pills? Well there are numerous naturally occurring plants from which potent plant sterols, vitamins & ingredients are extracted & used in testosterone support supplements. To explain further these supplements are not steroids or prohormone supplements but rather natural ingredients that work with your body & may support natural testosterone production within the normal range. Some commonly taken supplements of this type are tribulus terrestris, longjack, fenugreek & ZMA which are a safe and intelligent alternative to potentially dangerous steroids & prohormones.
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