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.     
Chemical Names: 4-androsten-3-one-17beta-ol 17beta-hydroxy-a ndrost-4-en-3-one
Estrogenic Activity: moderate
Progestational Activity: low
Testosterone enanthate is a slow-acting injectable spring of the androgen testosterone.
Coming after deep intramuscular injection, the drug is planned to offer a persistent release of testosterone into the bloodstream for about two to three weeks.
As with all testosterone injectables, testosterone enanthate is extremely preferred by athletes for its efficiency to advertise strong gains in muscle mass and force.
Testosterone enanthate is wide disposable in human an ( veterinary drug marketplaces. Composing and dose change by country and manufacturer, but generally involve fifty-one mg/ml, one hundred mg/ml, two hundred mg/ml, or 250 mg/ml of steroid ) soluble in oil.
Testosterone enanthate is a modified sort of testosterone.
The half-life of testosterone enanthate about 8 days after injection.
Side Effects (Estrogenic):
Testosterone is promptly aromatised in the body to estradiol (estrogen). The aromatase (estrogen synthetase) enzyme is liable for this metabolic process of testosterone. Raised estrogen levels could induce side effects specified raised water retention, body fat gain, and gynecomastia.
An anti-estrogen such as Clomid or tamoxifen citrate may represent required to prevent estrogenic side effects.
Side Effects (Androgenic):
Testosterone is the basal male androgen, liable junior upholding secondary male sexual characteristics. Raised rank of testosterone are likely to make androgenic side effects involving oily skin, acne, and body/facial hair growth.
Side Effects (Hepatotoxicity):
Testosterone doesnt have hepatotoxic effects; liver toxicity is unlikely.
In males with delayed puberty: Various dosage regimens have been used; some call for lower dosages initially with gradual increases as puberty progresses, with or without a decrease to maintenance levels. Other regimens call for higher dosage to induce pubertal changes and lower dosage for maintenance after puberty. The chronological and skeletal ages must be taken into consideration, both in determining the initial dose and in adjusting the dose. Dosage is within the range of 50 to 200 mg every 2 to 4 weeks for a limited duration, for example, 4 to 6 months. X-rays should be taken at appropriate intervals to determine the amount of bone maturation and skeletal development (see INDICATIONS AND USAGE and WARNINGS ).