Once testosterone enters the bloodstream, a part of it is converted into estrogen by a process called aromatization. Increase in the level of estrogen is responsible for side effects like water-retention, gynecomastia or male breast enlargement, and even higher levels of blood pressure and cholesterol. Many side effects related to estrogen can be countered by the intake of supplements that inhibit aromatase. Changes in blood pressure and cholesterol levels can also be controlled through a balanced diet rich in omega fats, and cardiovascular exercise.