Testosterone in particular has demonstrated in one clinical study to have only a mild impact on HDL cholesterol after a 12 week period where 280mg of Testosterone Enanthate was administered weekly. The cholesterol profiles had later changed for the worse when an aromatase inhibitor was included, which resulted in a significant 25% drop in HDL cholesterol  . Conversely, other studies have been conducted whereby 300mg weekly of Testosterone Enanthate was administered for a 20 week period without the use of an aromatase inhibitor which resulted in a 13% reduction of HDL cholesterol, however, when Testosterone doses were raised to 600mg weekly, reduction of HDL cholesterol had dropped to 21%  . From the data examined, it is very evident that the increase in Estrogen via aromatization and liver metabolism actually helps to offset the negative cholesterol changes from the use of supraphysiological amounts of anabolic steroids. This makes sense, considering Estrogen itself is known to promote positive impacts on cholesterol levels. Therefore, the use of an aromatase inhibitor and its impact on cholesterol profiles should always be remembered when any user is considering the addition of an aromatase inhibitor on cycle. It is advisable to instead use minimal doses of an aromatase inhibitor while on a cycle for the purpose of Estrogen control rather than total Estrogen level elimination. The idea in such a case is to keep Estrogen levels within normal ranges and not allow them to skyrocket as a result of aromatization, but at the same time prevent them from dropping to near zero from the use of full doses of an aromatase inhibitor.