The primary function of cholesterol in the body is to act as a building block for cell membranes, hormones, and vitamin D. Cholesterol is essential for maintaining cell structure and fluidity, allowing cells to function properly. Additionally, it serves as a precursor to steroid hormones, including sex hormones and corticosteroids, which play crucial roles in various physiological processes. While the body produces sufficient cholesterol, dietary sources can contribute to overall levels; maintaining a balance is important, as excess cholesterol can lead to health issues like cardiovascular disease.