The present invention provides methods for inhibiting or blocking TGF-β activity in cells and/or tissues expressing TGF-β comprising, contacting cells and/or tissues expressing TGF-β with an amount of cholesterol or cholesterol derivative effective to inhibit the activity of TGF-β. The present invention further provides a method for treating a condition associated with overactivity of TGF-β or negative regulation in normal physiology by TGF-β in a subject in need of treatment, comprising contacting cells and/or tissue overexpressing TGF-β in the subject with an amount of cholesterol or cholesterol derivative effective to inhibit activity of TGF-β thereby treating the condition. In a preferred embodiment, the cholesterol derivative is oxidized 7-DHC.