The body naturally converts Testosterone to Estrogen to maintain a fixed ratio.  Increasing Testosterone may create too much Estorgen resulting in unwanted fat covering your cuts.  Estrogen Blockers prevent this conversion. Estrogen blockers should be taken during cycle and during post cycle.

Many lifestyle habits affect the way testosterone is produced. A diet high in meat and poultry may expose a man to hormones used in meat production that act like estrogen in the body.

Estrogen is a potent inhibitor of testosterone production as are prolonged periods of high stress. Mild to moderately intense physical stress, as in casual sports and sexual intercourse, may actually boost testosterone production.

Also, prolonged increased estrogen levels can cause men to develop gynecomastia- gyno or breast cancer. Now that it's been established that there is a legitimate need for concern, is there a legitimate reason to use these products?

Alcohol consumption, on the other hand, has been proven to have a strong negative impact on testosterone levels. Beer, which contains plant estrogens, is particularly toxic to the male testes.

 As we all know, the testes are very heat sensitive so switching from jockey shorts and tight jeans to boxers and loose pants may raise the testosterone level.