Once we have added in the necessary testosterone, the next step is controlling the impending estrogen and progesterone activity that will result from the use of the Nandrolone hormone. This makes the use of anti- estrogens highly recommended; most will need an Aromatase Inhibitor (AI). However, if we suppress estrogenic activity too much, this can lead to complications; it can lead to sexually related side effects as well as damage cholesterol. Conversely, if we do not control estrogen and let the hormone run wild, high levels of estrogen can lead to gynecomastia , water retention and also negatively affect sexual function. Find the right balance of testosterone to estrogen and you will not have a problem when stacking Deca Durabolin.