1. Get a shower filter to lower chlorine levels. Maybe a whole house filter, too?
2. For more zinc, eat: oysters, meat, sprouted pumpkin seeds, cocoa, spinach and yogurt.
3. Use more glass, wood, natural fibers and stainless steel and less plastic. Examples: glass water bottle, bamboo keyboard and mouse, glass tuperware, stainless steel pot and kitchenware, 100% cotton sheets and clothes, tent without extra chemicals.
4. Get good sunshine earlier in the day to activate daytime body cycle.
5. Use coconut oil and butter.
6. Engage in healthy competition.
7. Consider high-quality probiotics – sauerkraut, kimchi, yogurt, etc.
Testosterone is significantly correlated with aggression and competitive behaviour and is directly facilitated by the latter. There are two theories on the role of testosterone in aggression and competition.  The first one is the challenge hypothesis which states that testosterone would increase during puberty thus facilitating reproductive and competitive behaviour which would include aggression.  Thus it is the challenge of competition among males of the species that facilitates aggression and violence.  Studies conducted have found direct correlation between testosterone and dominance especially among the most violent criminals in prison who had the highest testosterone levels.  The same research also found fathers (those outside competitive environments) had the lowest testosterone levels compared to other males.