Both triglycerides and cholesterol are different types of lipids circulating in the blood. Triglycerides are a type of fat circulating in your blood that the body uses for energy. Excess calories consumed are converted into triglycerides and stored for later use. Cholesterol, on the other hand, is a vital building block produced by the liver, used in the construction of cell membranes, hormones, and important compounds like Vitamin D.